Error in my tune-$100 to find it for someone

[67SS509]

Guess I have reached the point I am desperate enough to give someone $100 to show me whats wrong. I'm 99.9% sure it's in the software, probably with the injector tuning. Gets worse with increasing ECT temps. Breaks up and backfires under load when you try to go WOT in the 4000-6000 rpm range. AFR spikes up when it does but injector duty cycle stays up. Runs good around 125 degrees but goes to crap by 150 degrees ECT. Motor ran great in my truck but will not in the Camaro.

Some specs:
98 Camaro
LS7 427-large cam-ETP heads-GMMP carb style intake-90mm TB
Powerglide trans with 5600 stall
99-04 style computer and new stand alone harness
48lb Racetronic injectors
Aeromotive 1000 pump and system (fuel starvation is not the problem)
Truck coils
Base tune is from 2001 Camaro
Crank sensor and cam sensor have been checked and replaced and checked
No VSS
All grounds and + cables have been ohmned

Will PayPal $100 to whoever pinpoints the problem.

On the log start at frame 465 for the good WOT and frame 3142 for the one breaking up.

[LS1_Dragster]

Looks like a rev limiter to me! This looks like the dragster on the 2-step. You dont have an aftermarket ignition box or 2-step do you? Most likely not because of the temp but you never know.

There are just 2 things, 1) Fuel and 2) Ignition

You should include the injector pulse widths too

Are you positive the Fuel Pressure is stable at those trouble areas?

Lee

[SSpdDmon]

Why is B4004 zero'd out above 3600rpm?
Why does your desired airflow table have zeros in it?
Why did you adjust spark dwell times?
Why is your idle overspeed spark correction adding timing?
Why are the MAF DTC Processing Enablers disabled? -- this might be the key here. If the MAF tests aren't running, the MAF might not be failing...



I can't open your log without v7.5. But, what does your WB say is happening when it cuts out?

[5.7ute]

Why is B4004 zero'd out above 3600rpm?
Why does your desired airflow table have zeros in it?
Why did you adjust spark dwell times?
Why is your idle overspeed spark correction adding timing?
Why are the MAF DTC Processing Enablers disabled? -- this might be the key here. If the MAF tests aren't running, the MAF might not be failing...



I can't open your log without v7.5. But, what does your WB say is happening when it cuts out?

The log is showing a p0102 code so the maf is failing.
I havent done anything with the LS7 but wouldnt 24deg adv be on the high side for this combo. Is there any chance you are getting detonation? This can cause the lean readings you are seeing & will become more prevelant as engine temps rise.

[Highlander]

No,

Can you please log Maf Hz. Looks like the MAF is failing. If you see the first WOT run it appears to be ok... but you do not rev past 6krpm.

[Highlander]

You are running in speed density never mind... Let me look through the tune.

[Highlander]

Well....
Check to see if you have a bad coil.

Those lean spikes are misses.

[67SS509]

Thanks for the help here guys!
Attached is a log from today. Injectors are logged on this one.

To answer some of the questions............

-It is mafless
-B4004 table is stock from factory as trucks and f-bodies, Corvettes have this table filled all the way down. Filled my table and is included in the today's log. Didn't help.
-O's in airflow table...glitches from so many flashes I guess..corrected
-I have swapped out everypart on the car but the paint:wallbash:
-The only table with ECT involvement is B3702....Injection Timing...don't know what to try with this one
-Fuel is MS109 lead free VP Racing...ran 2 years on this with no problems
-If it was a real misfire from a bad coil or injector it would throw a code

[LS1_Dragster]

Why not use a tune for a manual trans instead of an auto? This is what I did for the dragster. Maybe there are issues the computer's having without any feedback from the auto trans.

I would find a tune for a manual and just copy over your fuel and spark tables.

Lee

[67SS509]

When I had the 98 PCM in it I did try a 6-speed tune but it did the same thing.

[LS1_Dragster]

I would still change it out so that it's correct!

[LS1_Dragster]

Get it on a dyno and hook up a timing light and see what happens... It has to be a spark issue, it just looks like a rev limiter. If it was fuel the wideband would reflect it.

[Highlander]

Not necessarily... it can be fuel and the wideband read incorrectly...

Still.. i feel its a coil issue as when it "heats" up it starts to act weird. The tune has nothing "wrong" that would make this happen... If it misses it will read lean.

[Highlander]

Thanks for the help here guys!
Attached is a log from today. Injectors are logged on this one.

To answer some of the questions............

-It is mafless
-B4004 table is stock from factory as trucks and f-bodies, Corvettes have this table filled all the way down. Filled my table and is included in the today's log. Didn't help.
-O's in airflow table...glitches from so many flashes I guess..corrected
-I have swapped out everypart on the car but the paint:wallbash:
-The only table with ECT involvement is B3702....Injection Timing...don't know what to try with this one
-Fuel is MS109 lead free VP Racing...ran 2 years on this with no problems
-If it was a real misfire from a bad coil or injector it would throw a code

Not necessarily. It can miss and not throw a code.

One more thing to try: Change the PCM.

[LS1_Dragster]

Wouldnt all the coils have to be bad in order to not let it rev? If one was bad it would just run bad but would still rev.

It does seem that the only thing left is to replace the computer.

Lee

[Highlander]

Too big of a miss on a few cylinders and you will have a problem.. I had a similar problem, changed ECUs and was done with it.

[67SS509]

This is the 3rd PCM I have tried. Thought the original 98 was bad and swapped it out. Then I converted to the 99-04 PCM with the new stand alone harness. Have changed the coil packs and then tried them on my truck and they ran fine. The injectors were new but I bought another new set and tried that. Second new set of MSD wires. Second set of new plugs. Second new fuel pump. Second new fuel regulator. 4 new crank sensors. 2 new cam sensors. 3 new TPS switches. Burned a 50 gallon drum of VP. Burned up a set of drag radials. I have spent thousands chasing this problem.

The reason I'm still using an auto trans base tune is because I'm still using the stock shifter and park/neutral switch.

I agree it only takes fuel and ignition, the right amount at the right time. I feel the amount is right but is occuring at the wrong time.

In the log today starting at frame 1237 I did a 5 sec blast. AFR looks normal and followed commanded along with everything else, but it was breaking up so bad it would not accellerate. It should have hit 7200 rpm. It just doesn't make any sense to me.

[LS1_Dragster]

So, your telling me that cold you can go out there and do a 5000 to 7000 RPM blast and log it?

Is it possible that you have the injector wiring wrong and it's firing the injectors in the wrong sequence?

Maybe this could be resoned because the injector timing cold is fired at a different time.

Change B3702 and B3703 all to 2.55 and see if it will rev....

[67SS509]

So, your telling me that cold you can go out there and do a 5000 to 7000 RPM blast and log it?

Is it possible that you have the injector wiring wrong and it's firing the injectors in the wrong sequence?

Maybe this could be resoned because the injector timing cold is fired at a different time.

Change B3702 and B3703 all to 2.55 and see if it will rev....

If I'm reading this table right with temp increase the injectors wait longer to open. Wonder what GM's reasoning was for this? Faster burn rate when hot?

[joecar]

If I'm reading this table right with temp increase the injectors wait longer to open. Wonder what GM's reasoning was for this? Faster burn rate when hot?My understanding: when cold the sprayed fuel takes longer to evaporate; when hot it evaporates sooner.

[5.7ute]

My understanding: when cold the sprayed fuel takes longer to evaporate; when hot it evaporates sooner.

That is how I understand it too Joe.
FWIW I would be pulling timing to see if the problem goes away. Standard knock sensor settings could be incorrect for the new position of the sensors.
I would also be triple checking ALL of my earths, these can have a tendency to only show issues when hot.

[LS1_Dragster]

Actually, I think most people agree the larger the value the sooner it fires the injector in relation to TDC.

Recently I've read articles about firing the injector closer to TDC for emissions which does make sense. For example, fuel in a cold port is in no way going to atomize, it would just pool up big time, but firing the injector when the valve is open it would be drawn in directly without pooling up.

I guess if the injector wiring is incorrect it should still run OK. I base this on batch fire injection and batch fire works fine.

So I'm back to thinking it's timing, go to a dyno and watch what the timing is doing.

Again, you can do a 5000 to 7000 RPM blast when cold?

Lee

[5.7ute]

So I'm back to thinking it's timing, go to a dyno and watch what the timing is doing.


Lee
That was my thoughts from the beginning. Once ECT has increased detonation is occuring.
Another maybe is an exhaust blockage, but I would have thought the wideband would read rich if this was the case.

[LS1_Dragster]

Another maybe is an exhaust blockage, but I would have thought the wideband would read rich if this was the case.

That occurred to me a long time ago because I was trying to figure out what's different between both vehicles but I ruled it out (sort of) because he said it works cold. This is why I asked twice if the car will rev to 7000RPM cold for sure, if it does then that's not the problem

[5.7ute]

That occurred to me a long time ago because I was trying to figure out what's different between both vehicles but I ruled it out (sort of) because he said it works cold. This is why I asked twice if the car will rev to 7000RPM cold for sure, if it does then that's not the problem

It will rev from 5000 to 6000rpm when cold. But will not when warmer. I dont think he would need to try shoot for a 7000 rpm run.

[Highlander]

I agree also with the grounds. I don't think its timing.. 24 advance is adequate for these engines.

[chevy052500hd]

Have you verified fuel pressure with a gauge while doing a run? To make sure it doesn't drop off?

[LS1_Dragster]

Have you verified fuel pressure with a gauge while doing a run? To make sure it doesn't drop off?

If it did it would show on the wideband AFR.

His first log showed lean spikes but the second one does not.

A puzzle for sure!

[LS1_Dragster]

It will rev from 5000 to 6000rpm when cold. But will not when warmer. I dont think he would need to try shoot for a 7000 rpm run.

I would like to see that in a log......

EDIT: I went back and looked at the first log and he was able to get more RPM cold, soo......I dont know! A real mystery for sure.

[67SS509]

Made some more changes today but still no better. Also added a quick and rough vid so everyone can hear it also. In the vid it sounds just like a rev limiter but in the car you can hear how erratic it is. Low and high gear run starts at frame 1007.

One more thing that has puzzled me for a while is how perfect it holds the timing at 24* when I go WOT. I would think it would hit more timing cells then that. I keep looking at table B5912 and wondering.

http://i219.photobucket.com/albums/cc163/67SS509/th_CamaroRunAug28-09.jpg (http://s219.photobucket.com/albums/cc163/67SS509/?action=view&current=CamaroRunAug28-09.flv)

[LS1_Dragster]

That has to be a rev limiter!!

Why dont I give you the tune for my dragster and just copy over your fuel only tables and see what happens? Nothing but the fuel tables.....

Lee

[67SS509]

That has to be a rev limiter!!

Why dont I give you the tune for my dragster and just copy over your fuel only tables and see what happens? Nothing but the fuel tables.....

Lee

I knew it.....everybody that listens to the vid will say rev limiter:grin:

I'm really glad you gave me your tune. When it quits raining I'll give it a try. Haven't looked yet but what size injectors are you running?

[LS1_Dragster]

I still think the computer is going into some weird mode like protection mode or something and is limiting your RPM's. I really hope that this tune will work for you, obviously the fuel segment will need to be changed but the rest should work OK for you.


The injectors are Accel 36# @ 45# fuel pressure.

I hope it stops raining soon!

I keep forgetting tunes dont work on all computers, I'm not sure if you can actually use mine or not...

FWIW, I get my 0411 computers from the wrecking yard for $40, I dont know if there are any advantages for you or not....Also, why not upgrade to a custom OS?

[swingtan]

Why is there a big step in the timing table at 1gm/Cyl?

The initial log and tune shows that you are reaching 1.08gm/cyl which should be commanding 21' timing, not the 24' logged. I'm still thinking that it's something else ( though it does sound like the limiter ). Here's the kicker.... The Engine Protection Mode timing is set at 24' ( B5912 ). That matches the logged timing so I'm going to say that's the first place to look.

You are locked on 24' timing from 4,000 RPM all the up through 6,000 RPM. I was thinking that it may be oil pressure related, but you have all the DTC's turned off. If it's like the MAF DTC's then the PCM should ignore the oil pressure codes and not go into protection mode. I'd rather see them turned on though, unless you have some other method of monitoring oil pressure. I'd like to at least see oil pressure in a log to confirm it's OK when hot.

So my call is "Engine Protection", just need to work out why. Actually, you could confirm it by altering the timing in B5912 and seeing if the timing values match in a WOT run. Oh, and I'd fix that spark table as well.

Simon.

Edit: I take it you have scanned for DTC's ?

[5.7ute]

Well spotted Simon.
I had a quick look through an ls7 tune & couldnt find a table for oil pressure v rpm. There is the possability that the ls7 runs lower oil pressure at those rpms, tripping the mode with the ls1 settings but I cant confirm this.

[67SS509]

I still think the computer is going into some weird mode like protection mode or something and is limiting your RPM's. I really hope that this tune will work for you, obviously the fuel segment will need to be changed but the rest should work OK for you.


The injectors are Accel 36# @ 45# fuel pressure.

I hope it stops raining soon!

I keep forgetting tunes dont work on all computers, I'm not sure if you can actually use mine or not...

FWIW, I get my 0411 computers from the wrecking yard for $40, I dont know if there are any advantages for you or not....Also, why not upgrade to a custom OS?

99-04 PCM's are the same. I just did a full reflash and your tune is in. First wierd thing was with my VE table and injector flow rate it was real lean idling and revving (still raining-can't drive it). 10 minutes on the wide band and it follows commanded, idles great and revs so hard you would think it's going to sling the planetary out of the powerglide.

Another thing to note is in the COS3 you use, the open loop commanded table follows rpm and MAP instead of ECT and MAP. I believe this going to make a big difference. Maybe tomorrow will tell.

[67SS509]

Why is there a big step in the timing table at 1gm/Cyl?

The initial log and tune shows that you are reaching 1.08gm/cyl which should be commanding 21' timing, not the 24' logged. I'm still thinking that it's something else ( though it does sound like the limiter ). Here's the kicker.... The Engine Protection Mode timing is set at 24' ( B5912 ). That matches the logged timing so I'm going to say that's the first place to look.

You are locked on 24' timing from 4,000 RPM all the up through 6,000 RPM. I was thinking that it may be oil pressure related, but you have all the DTC's turned off. If it's like the MAF DTC's then the PCM should ignore the oil pressure codes and not go into protection mode. I'd rather see them turned on though, unless you have some other method of monitoring oil pressure. I'd like to at least see oil pressure in a log to confirm it's OK when hot.

So my call is "Engine Protection", just need to work out why. Actually, you could confirm it by altering the timing in B5912 and seeing if the timing values match in a WOT run. Oh, and I'd fix that spark table as well.

Simon.

Edit: I take it you have scanned for DTC's ?

I had already guessed it was running timing based on the b5912 table at WOT but can't find anything that triggers it. I assume massive air flow is doing it but can't find anything to change and stop it. Car has a full set of Autometer guages to monitor things. I try to stay on top of DTC's, just can't do anything with PO102 MAF code, won't run without it.

[LS1_Dragster]

It should run much better and easier to tune. Also look at B3647, this is where you will command your AFR. Also, use A0008 for your cold startup, increase these numbers so your not so lean at start up.

[LS1_Dragster]

Our dragster revs like no tomorrow too, it sound much meaner then it really is! I'm putting on a vortech supercharger this winter, it should make the dragster even more fun.

[67SS509]

Well spotted Simon.
I had a quick look through an ls7 tune & couldnt find a table for oil pressure v rpm. There is the possability that the ls7 runs lower oil pressure at those rpms, tripping the mode with the ls1 settings but I cant confirm this.

My setup is a wet sump. Pressure holds at 45 idling and 60+ above 2000 rpm's. Low oil pressure is a check guages warning only. Some models interlock low oil level with fuel pump. Mine does not.

[LS1_Dragster]

Also, put B3702 and B3703 to my numbers, I proved this to reduce my et considerably on 2 occasions. It will also change your AFR at idle. Again, raise A0008 to what ever your car likes warming up.

[swingtan]

I had already guessed it was running timing based on the b5912 table at WOT but can't find anything that triggers it. I assume massive air flow is doing it but can't find anything to change and stop it. Car has a full set of Autometer guages to monitor things. I try to stay on top of DTC's, just can't do anything with PO102 MAF code, won't run without it.

The P0102 code is needed to force the PCM into SD mode. It's fine to leave that DTC alone as it'll come back every time you start the car. If you disable the DTC, the PCM won't know that the MAF has failed and will still try to use it for air flow measurements. If it's not there, then the "measured" sir flow will be "0" and the PCM will cut the fuel.

The Oil DTC's however probably should be set to work though. They should capture any oil pressure changes and set an error code to suit. The other way would be to simply log engine oil pressure all the as there is always a chance that you could miss a sudden drop in oil pressure while watching the road. I'm also not sure if the PCM will act on a low oil pressure trigger even if the DTC is not set.

You may be right with the air flow settings, as the increase in air flow may be triggering "limp home mode". Again, this should set a DTC and the air flow DTC's do appear to be turned on.

Actually, I did notice that the Engine Protection timing comes in at 4,000 RPM and stays there all the way up. It only changes as you approach the 4,000 RPM mark again. I wonder if B0120 has an effect on this? Given you are running SD and it shouldn't make any difference, I'd set this to say 7,500 RPM or 400 RPM and see what happens ( actually, I'd do both and see if there is any difference ). I wonder if the PCM is still calculating AIR flow and as you cross the 4,000 point, it drops into protection mode.

Simon.

[vxchev8]

In power enrichment mode you are commanding 14.63. Only skipped through the thread, sorry if it has already been mentioned.

[Cablebandit]

24 degrees is what it shows for protection mode so i would guess oil pressure sending unit...and like was also said you are asking for 14.63 afr in PE mode

[LS1_Dragster]

He was in SD mode so the PE isnt being used, it's using B3605 to command WOT AFR.

[LS1_Dragster]

Any updates?

[67SS509]

Any updates?

Had to give it a rest for the weekend. This problem has about burned me out. Went racing last night. The competion is getting so fast. 3.9x secs. in the 1/8 mile, stock suspension cars in the 4's, next they will be going to the moon:grin:

I'll be back on it tomorrow and will post the results.

[SSpdDmon]

He was in SD mode so the PE isnt being used, it's using B3605 to command WOT AFR.
Even in SD, the PCM will take the richer value of either the PE or Commanded AFR in Open Loop tables when the PE thresholds are met. This is true because I tune a little different from what the tutorial suggests by setting my OL table to 14.6:1 across the board once the engine is up to temp (i.e. all columns=14.6:1 when ECT >160*F) and my PE to the values I desire for WOT. This simulates how the car performs from the factory in closed loop operation....commanding 14.6:1 until PE kicks in.

[LS1_Dragster]

I can see the benefit of doing that unless you are using a custom OS...

[67SS509]

Finally got to make a run this evening. The problem is still bad as ever. Log is attached.

Started removing the fuel tank to try something different on the sump. Engineer at Aeromotive thinks it's got a big pressure drop on the suction side of the pump. That's causing flashed fuel (call it air bubbles) getting to the injectors. I'll post updates on this. Probably will take a few days to try something.

[LS1_Dragster]

Why would the temps be a factor then? I guess its coincedental....

[5.7ute]

Why would the temps be a factor then? I guess its coincedental....

I have noticed with higher octane pump fuels here a tendency for the pump to cavitate with temperature. My 044 pump screams like a kid at the candy store once ambients get up to around 30deg C.
I do not believe this to be the issue here though.

[LS1_Dragster]

I do not believe this to be the issue here though.

I dont think so either, I would assume the AFR would be out the roof, Gotta be spark...... Even though we dont see the spark being changed by the computer.

[LS1_Dragster]

Any chance it's mechanical such as valve float? Broken spring(s)?

[jetblast]

i know you said the cam sensor was changed, but that is the circuit i would be checking to make sure the pcm is getting a clean signal, that would include the connector pins at the sensor and pcm and any other connectors in between . i would get a scope in the hole and do a visual ck. of the teeth. the sprocket on the ck shaft is or should be spot welded on or else it can brake loose or so i heard. i would also try another pcm. it sure seems as though the pcm is not able to fire the plugs on time and thats why you are backfiring. did you actually change the engine protection timing to 22 or even 18 to see if it fallows? that certainly would not mean much except that the pcm is comanding eng. protection mode for perhaps the lack of a good timing signal.

[LS1_Dragster]

jetblast - he actually uploaded my custom OS and tune so to me that eliminated any issues with the tune.

I believe he's changed out the computer too.

If it was a sensor or loose teeth etc. then why does it run good up to a certain RPM? And why does temp play a part?

I cant wait for the answer, this would of driven me nuts if it was mine!

Lee

[67SS509]

Too late, it has driven me nuts...going to check in at Vallyview Nut House tomorrow.:hihi:

I have checked the reluctor wheel (reluctor wheel is spot welded) and cam gear with a Snapon boroscope. Sensor gaps are on factory specs. Spaced them till they throwed a code so they must be working right.

Made some changes on the fuel system yesterday. Aeromotive is satisfied now that the fuel is not a problem but it is still doing the same thing.

I have went back to old school reasoning. If someone brought an old big block Chevelle to me with the same symtoms I would would be looking at the ignition system. I'm going to make something so I can check it with a timing light and then an osciliscope. I feel what's happening is occuring in the cylinder.....peak at the wrong time or weak...just have no idea what can be causing it.

[LS1_Dragster]

On my LS1 I just put the #1 to TDC and marked a line on the balancer. Not very accurate but it does let me check it.

BTW, can you rev it to 6000 while stationary? I myself hate doing that but maybe if you mark your balancer and just rev it to 6K maybe you'll be able to see if the timing freaks out. This is why I suggested a dyno, it can be done safely and under load.

[jetblast]

i really think he should log a wot run from 3.5krpm to 6krpm, with ect temps at 130,160, and the highest temp that his thermostat is rated at respectively. also, i would like to see mph along with the rest of the inj. data. and finally i would change the b5913 to different timing values to see if the pcm actually follows and comands as the rpm rises from column to column. well if he excluded the pcm, then the connectors for that circuit have to be ckd., he said th idc continues to climb and so a clear indication that the pcm is not cutting out the injectors. really seems to me that the timing signal is breaking up, it's possible that ect temps are a factor, but won't know for sure until he logs clear identical rpm excursions under different temps. as you know materials expand as temperature encreases, so that's one potential but highly unlikely cause, also as temperature rises electrical circuits are not as efficient. maybe if he swaps the harness with a known good one to exclude that as the culprit.

[LS1_Dragster]

jetblast - I agree on making a cold run, I mentioned this several pages back but I'm not sure what it will really tell us now.

Also, his timing has changed, it's now using my timing!!! It was originally locked at 24 and now it's 27 at WOT and 35 at idle.

No MPH, he's running a glide.

I cant figure out what would cause the timing to not follow the commanded timing, but a timing light and a few zings to 6K should tell us if the timing is the culprit.

I would also look at the following:

1) valve springs
2) crossed wiring to the injectors
3) low voltage to the coil packs - there are 2 12v feeds, these same feeds run the injectors, I would make sure the wire and fuse feeding them are the correct sizes. A volt meter with memory should let you know. Just hook up the volt meter and do a run and see what the voltage does. I guess you could even run a wire to the cab and have a passenger watch the volt meter, but this has to be wired directly into the coil pack 12v feed. Hell for that matter you could run a temporary 12v line and tie directly into the coil packs and also do the same with a ground, just splice it right in, this would take care of any ground or power issues!

Just throwing wild ideas out....

[gtore62]

i could see the eng. having trouble reving past 4k or 5k rpm due to one or two bad coils not fireing, which should show a lean condition. if all coils fail or fire at the wrong time then i would supect what ever is common to all. one other thing he could do is monitor egt at the cylinders.

[Highlander]

Check your reluctor then.. is this a retrofit like the X24 from eficonnection?

if you reluctor looses signal you will have issues JUST LIKE THIS ONE... I thought this was a factory system... Even if you do not throw a code, the PCM could loose synch or doesn't exactly know what it's doing...

The reluctor MUST have a dual pattern in order to work correctly...

[joecar]

If you can get an automotive oscilloscope, check the following waveforms for correctness:
- CKP sensor,
- Ignition secondary (use a capacitive probe),
- Injector drive (as a sanity check).

In particular, the ignition secondary waveform can point to weak/broken coil, broken wire/plugs.

(the capacative probe waveform follows the secondary/primary voltage, whereas the inductive probe waveform follows current).

[67SS509]

On my LS1 I just put the #1 to TDC and marked a line on the balancer. Not very accurate but it does let me check it.

BTW, can you rev it to 6000 while stationary? I myself hate doing that but maybe if you mark your balancer and just rev it to 6K maybe you'll be able to see if the timing freaks out. This is why I suggested a dyno, it can be done safely and under load.

My balancer is an ATI which is degreed the full 360*. The balancer is zeroed to TDC, just don't have a tab set up. It's hard to determine TDC exactly with the engine in the car.

I have revved it past 7000 and just referenced the timing light to a mark I placed on the block. Did not see anything out of place.

[67SS509]

Any chance it's mechanical such as valve float? Broken spring(s)?

Pretty sure it's not valve springs. It's has the Patriot Golds. I also had looked at them when I removed this engine from my truck and installed it in the Camaro.

[67SS509]

Check your reluctor then.. is this a retrofit like the X24 from eficonnection?

if you reluctor looses signal you will have issues JUST LIKE THIS ONE... I thought this was a factory system... Even if you do not throw a code, the PCM could loose synch or doesn't exactly know what it's doing...

The reluctor MUST have a dual pattern in order to work correctly...

This engine has a Callies Magnum crank with 24 reluctor wheel and it's spot welded on.

[67SS509]

If you can get an automotive oscilloscope, check the following waveforms for correctness:
- CKP sensor,
- Ignition secondary (use a capacitive probe),
- Injector drive (as a sanity check).

In particular, the ignition secondary waveform can point to weak/broken coil, broken wire/plugs.

(the capacative probe waveform follows the secondary/primary voltage, whereas the inductive probe waveform follows current).

How do you check injector drivers?

[67SS509]

How does not having anything connected for the VSS affect the PCM. Does it think it's standing still and idling all the time? Just thinking out loud before I start babbling to myself.LOL

[LS1_Dragster]

How does not having anything connected for the VSS affect the PCM. Does it think it's standing still and idling all the time? Just thinking out loud before I start babbling to myself.LOL

Yes. It has never caused any problems with our dragster.

So the timing stayed put and didnt move at all when you revved it to 7K?

[67SS509]

Yes. It has never caused any problems with our dragster.

So the timing stayed put and didnt move at all when you revved it to 7K?

I have an engine on a stand that I'm going to set on TDC and then make a bolt on pointer tab that I can transfer to the 427. Then I should be able to perform this test with good accurate results.

Just curious about something. In your dragster, is your 5000 stall converter an 8" or 9"?

[LS1_Dragster]

The timing doesn't have to be accurate, the goal is that it's steady and doesn't move while revving it.

The converter is a Coan 8", way too tight but they argued with me endlessly. I felt it should be at 6000RPM stall, they said it would be on the converter the entire time. I'm leaving it alone for now since I will be adding a supercharger this winter.

I have another one that also stalls at 5K in the 1800lb dragster, will stall more in a car if anyone is interested in....

[joecar]

How do you check injector drivers?You can do this several different ways:

Remove the connector (can do this while engine is running) and plug a noid light into the connector, noid light has same impedance as injector and will flash with each trigger... do this for all 8 driver circuits.

If you have an oscilloscope, capture a waveform of the injector driver circuit voltage wrt to vehicle ground... and if you have a current clamp capture the current waveform on the injector positive side wire... these two waveforms will also show dips/bumps where the injector pintle physically opens/closes... you would have to do this for each injector driver and compare all 8 waveforms... see attached image for example (2001 LS1 Firebird).

http://usera.imagecave.com/joecar/Injector%20Response.png

The open dip and the close dip verify that the injector physically moved...

Do you have access to a scope...?

:)

[joecar]

If you look at ignition secondary on the scope, you can tell if the spark fired successfully by the duration of the arc, see attached...

In this capture, I had my current clamp wrapped around the fuse that feeds both injectors and coils on bank 1 (using a wire loop with fuse lugs on each end), so you can see injector current and coil primary current.

[67SS509]

If you look at ignition secondary on the scope, you can tell if the spark fired successfully by the duration of the arc, see attached...

In this capture, I had my current clamp wrapped around the fuse that feeds both injectors and coils on bank 1 (using a wire loop with fuse lugs on each end), so you can see injector current and coil primary current.

Thanks Joecar! I have a friend with an almost new Snapon scope. He doesen't know how to use it. I have been looking at the manual for the past week when I have time. I'm still aways from trying it and real close to brainburn at this time.

[chevy052500hd]

do you have a stock prndl switch hooked up? If the pcm thinks it is in park you would have a rev limiter. You could also adjust that in the tune too.

[joecar]

Here's what the CKP and CMP waveforms would look like for the 24x Gen III reluctor...

This was an example someone sent me from a 6.0L Gen III truck.

[joecar]

Thanks Joecar! I have a friend with an almost new Snapon scope. He doesen't know how to use it. I have been looking at the manual for the past week when I have time. I'm still aways from trying it and real close to brainburn at this time.If the Snap-On scope has common ground inputs for all channels, then connect the grounds to vehicle ground only...

do not connect any scope grounds across an injector or sensor as this may damage the scope...

the ground inputs have to be at vehicle ground;

i.e. all input channels are measuring wrt to vehicle ground...

the Snap-On manual would have a warning about this.

[LS1_Dragster]

do you have a stock prndl switch hooked up? If the pcm thinks it is in park you would have a rev limiter. You could also adjust that in the tune too.

You guys need to read all the posts!!

The tune that he's using right now is from my dragster also with a glide, no VSS, no nothing. BTW, no provison to hook up electronics with a glide.

There are 2 tables that you can set the rev limiter with, it's the same limit in PN and drive!!

A few pages back I posted the tune file, everyone is welcome to look at it.....

Lee

[chevy052500hd]

I had a situation on a dune buggy where the pcm for some reason needed to see it was in drive so I had to rig up a toggle switch to get it to ground the prndl wires in the right way in order to get it to work. May not be your situation, but for me it needed to be done. I even had the rev limiters changed to match in my tune.

[LS1_Dragster]

I had a situation on a dune buggy where the pcm for some reason needed to see it was in drive so I had to rig up a toggle switch to get it to ground the prndl wires in the right way in order to get it to work. May not be your situation, but for me it needed to be done. I even had the rev limiters changed to match in my tune.

Weird, lucky it works in my case, maybe the custom OS is more forgiving.

One thing I've learned since working with factory computers is there is no way to understand why the GM engineers did the things they did. They made it far more complicated then needed in my opinion.

I would like to see a scaled back custom OS that just has the basics, especially for off road use.

Lee

[joecar]

If the problem can't be found, then providing PRND inputs should be tried... either that is the answer or it can be ruled out.

[LS1_Dragster]

If the problem can't be found, then providing PRND inputs should be tried... either that is the answer or it can be ruled out.

Why would my dragster work perfectly? If he is using the same tune as mine wouldnt it also work?

[joecar]

Why would my dragster work perfectly? If he is using the same tune as mine wouldnt it also work?You do have a very good point and I agree with you...

he should still do the experiment to rule out that possibility (especially since the problem has no solution yet...).

[LS1_Dragster]

I agree, at this stage I would of put the engine back in the car that worked! Just to see if it still worked or not.

[TFZ_Z06]

Guess I have reached the point I am desperate enough to give someone $100 to show me whats wrong. I'm 99.9% sure it's in the software, probably with the injector tuning. Gets worse with increasing ECT temps. Breaks up and backfires under load when you try to go WOT in the 4000-6000 rpm range. AFR spikes up when it does but injector duty cycle stays up. Runs good around 125 degrees but goes to crap by 150 degrees ECT. Motor ran great in my truck but will not in the Camaro.

Some specs:
98 Camaro
LS7 427-large cam-ETP heads-GMMP carb style intake-90mm TB
Powerglide trans with 5600 stall
99-04 style computer and new stand alone harness
48lb Racetronic injectors
Aeromotive 1000 pump and system (fuel starvation is not the problem)
Truck coils
Base tune is from 2001 Camaro
Crank sensor and cam sensor have been checked and replaced and checked
No VSS
All grounds and + cables have been ohmned

Will PayPal $100 to whoever pinpoints the problem.

On the log start at frame 465 for the good WOT and frame 3142 for the one breaking up.

Hi, hows it going, just a few observations:

1. Spark seems high at 28 for a 427.

2. Desired Airflow appears too low for a big cam. I would expect it to run rich and non-responsive through the powerband and have an idle that decays too quick as a result with those settings. Remember, this is just an observation but is based on several cams I have used in the past from 216 to 254 degs duration @ 0.050.

3. Fuel injectors look as if they are scaled in the lean direction at higher KPA values. The low KPA looks ok, but if those are the flow rates, those are the rates I guess. This would definitely cause the high VE numbers though.

4. The VE table seems way too high in the high KPA area. 118 for example.
My engine in sig is less than 100, not that this is absolute I'm not sure if it matters much if the VE compensates for the leaner injector setting or not, just a thought.

5. Cyl volume should be around .2c.i. larger?

6. Why not set PE VS RPM to a richer setting? PE vs RPM works on my processor in SD no MAF mode.

For what its worth, just a quick glance leaves me wondering about the Desired Airflow ( and whats with Park/NeuTral column sort of mixed up) and PE vs RPM setting.

[67SS509]

Spent another Saturday on the "Pyscho Camaro". I'm trying to maintain some humor here but I really have about reached the end of the rope on this one. Did some scope work on it today and made a couple road runs. Only real change made to the car was I added a shield to the crank sensor wires to make sure there is no noise getting on them from secondary ignition. In the attached log there are several WOT blasts..all had breaking up and just would not pull the rpm's this motor is capable of. Starting at frame 1930 you can actually see the injectors cutting back but why?

Attached are pics of the scope looking at crank sensor pulses and cam sensor pulses. They look like the ones Joecar presented. Also did a scope of the secondary ignition but forgot to take a pic. Compared them to another vehicle and could not see anything different.

The car still has the park/neutral switch. My understanding is that it just interlocks with the starter and cranking. The only way the PCM knows the car is moving and not parked is from the VSS, rpms and what it's commanding to the solenoids in the transmission when it is an automatic. With this tune it thinks it's a six speed so all it knows is VSS and rpm's. That's my story and I'm sticking to it:hihi:

Don't have a game plan for my next move................

[joecar]

If the injectors are cutting back then the PCM is exercising some limiter...

Do you have a scope picture showing both CKP and CMP waveforms at the time the problem happens...

(the CKP sensor must be ok otherwise you would get to any RPM)

Did the ignition waveform look ok (sufficient spark duration is about 2+ milliseconds).

[jetblast]

did you change the eng. protection timing from 24 to something lower? the log shows a flat line timing value of 24 at wot. i would change that table to 21*, flash the pcm and run it at the suspect ect. if the changes you made do not follow then you can exclude protection timing. then i would change the high oct. timing tables to something other than 24*. another point, i reviewed the wiring diagram for my 04 gto pcm power supply and the low reference signal for the coils, bank 1 and 2 have one common connection amongst all which is the low reference signal and think they all meet at somewere inside the harness just downstream of the connector that powers the coils, the injectors and coils also share the power supply and they should all meet somewhere inside the conduit in the eng. intake area. the low reference signal wire is brown on both banks, the power supply wire is pink on both banks for the coils and light green for the injectors on bank 1, and red on bank 2. i know you have a dragster, but hopefully this helps. the low reference signal wire goes directly to the pcm without any breaks. the power supply is the one common to both the inj. and coils and it goes from the eng. harness by the intake to the fuseblock, 15 amp fuse.

[Highlander]

Honestly. I would check there is NO play on the crank front and back.

[jetblast]

Honestly. I would check there is NO play on the crank front and back.

assuming the circuit is intact with solid electrical contacts at the junctions and connectors and pins, then that certainly is a valid point. i would however, bypass the harness and feed the coils with the low reference signal directly from the pcm, and finally feed the coils directly from the fused power supply. you would think the harness is compatible with the pcm he has now due to the fact that the eng. "runs ok when cold". that's why i would log 3 runs with identical rpm starts and slow throttle encreases until it begins to break up, and of course one would be cold, one warm and one hot. THE ENGINE RAN FINE IN THE TRUCK, BUT NOT IN THE CAMRO, but at what rpms?

[joecar]

Honestly. I would check there is NO play on the crank front and back.Good point... this would show up on the CKP waveform.

[joecar]

...bypass the harness and feed the coils with the low reference signal directly from the pcm, and finally feed the coils directly from the fused power supply... ...THE ENGINE RAN FINE IN THE TRUCK, BUT NOT IN THE CAMRO, but at what rpms?Good point, wiring problems sensitive to heat/vibration...

he needs to capture ignition secondary waveforms (all 8) and injector waveforms (all 8) when problem happens.

[swingtan]

Was the cause of the "Engine protection mode" ever found? While it's good to explore all angles, I'd be concentrating on why the PCM was going in to protection mode. If there are known issues in the tune, I'd be fixing them up before looking into other things.

My reasoning is that the miss seems to be very repeatable. Loose wires, intermittent connections and things like that would produce more of a random miss in the engine.

Simon.

[LS1_Dragster]

Was the cause of the "Engine protection mode" ever found? While it's good to explore all angles, I'd be concentrating on why the PCM was going in to protection mode. If there are known issues in the tune, I'd be fixing them up before looking into other things.

My reasoning is that the miss seems to be very repeatable. Loose wires, intermittent connections and things like that would produce more of a random miss in the engine.

Simon.

I dont believe it's going into protection mode, the assumption was because it was 24 degrees at WOT. He installed my tune and it changed to 27 degrees where I have it plus in my tune it's 10 degrees in protection mode.

Lee

[67SS509]

Made another change today and seen a major improvement. I would say problem is solved but I did hear one high rpm miss. I closed the gap on the plugs from .030" to .024". I got to thinking maybe it was blowing the spark out. I know this is a non boosted engine but the heads do flow close to 400cfm. For the record plugs are NGK heat range 7. Ran it up to 6500 in high gear and it felt strong. Couldn't make anymore runs today because rain set in. I don't really understand why the improvement because I have ran this plug at the .030" gap for over 2 years. The only change is the carb style intake versus the stock LS7 intake and 48lb injectors versus 42lb.

I think I'm going to try a "cut back style" plug next. This thing is set up for a 400hp shot of nitrous so this might be needed anyway.

[joecar]

You would have seen this in the secondary waveform capture... the spark duration line would have been cut short.

I know the scope can be a handfull when engine is running and your attention has to be split...

Post some logs.

[LS1_Dragster]

wouldn't this imply there's an issue with the coils? And or voltage?

[joecar]

Or maybe even the spark plug wires... they may have breaks in them contributing to the "total" gap...

[67SS509]

Remember, it's the truck coils. The wires are MSD's. I swapped both out with the truck and the truck runs fine on either set (.035" gap on TR6 plugs).

[LS1_Dragster]

Then look at your supplied voltage under load! Or just run a new wire directly to the coil pack supply.

[67SS509]

I have tried jumper wires from the battery cable directly to pink supply wires to the coils and the injectors. Have also jumpered the ignition. But remember this is a brand new stand alone harness also.
On my dashboard I always log voltage so it's in the PID's if you want to have a look at it. Went thru 3 alts. to get one that maitained 14+ volts.

I think this one is going to make us all smarter when it's fixed. I have learned 2 times more than I thought I knew.............

[LS1_Dragster]

The way I see it, since you shortened up the gap and it runs better then that clearly indicates there is not enough voltage to jump the gap.

So what effects that?

1) Voltage and AMP'S to the coils
2) Volts/amps to the plugs
3) How long the coils are saturated

There may be more factors that I don't know about.....

[67SS509]

The Snap-On measured the dwell at 34* if I was reading it correctly. That should enough I think.
I agree that we have narrowed it down to weak voltage.

[5.7ute]

The collapsing of the field is just as important as the input voltage to get a strong spark. For a quick, cheap test I would be adding a few extra earths to the system.

[joecar]

Do you have an amp clamp probe for the Snap-On...? If you do, pick a coil and clamp the probe around the power wire for that coil, and capture the coil current... and also capture the secondary voltage from that same coil capacitive probe)... your Snap-On is dual channel, right...

The current waveform has to have a specific shape if the coil is charging right;
the secondary firing spike indicates how much energy is being demanded to jump the gap (the lower the spike the easier it is to jump the gap).

What is the dwell time in ms...? What is the spark duration in ms...? The Snap-On has on-screen cursors, use those to make measurements. Post some screenshots from the Snap-On. Does the Snap-On have a save-to-PC-via-USB feature...?

[swingtan]

I dont believe it's going into protection mode, the assumption was because it was 24 degrees at WOT. He installed my tune and it changed to 27 degrees where I have it plus in my tune it's 10 degrees in protection mode.

Lee

Cool, I'd missed that.

Now to find the root of the spark issue.....

[67SS509]

Do you have an amp clamp probe for the Snap-On...? If you do, pick a coil and clamp the probe around the power wire for that coil, and capture the coil current... and also capture the secondary voltage from that same coil capacitive probe)... your Snap-On is dual channel, right...

The current waveform has to have a specific shape if the coil is charging right;
the secondary firing spike indicates how much energy is being demanded to jump the gap (the lower the spike the easier it is to jump the gap).

What is the dwell time in ms...? What is the spark duration in ms...? The Snap-On has on-screen cursors, use those to make measurements. Post some screenshots from the Snap-On. Does the Snap-On have a save-to-PC-via-USB feature...?

Yes, it does have a amp clamp-on but it is not a dual trace. I played with this some today before reading your post here so I don't have specific numbers to your answers. What I did not knowing the values to be looking for was to compare the peaks and duration to my stock 05 Chevy truck. Instead of using the cursor I just turned the grid on for measurement. They both looked the same. This unit is 10+ years old and only has the capability to freeze and send to a printer. I'll try it again tomorrow and post some shots.

I have reviewed all the grounds and feeds again today.
-positive and negative cables are from battery to motor, pcm, accessories and starter with 3 large grounds from motor to body. Also a large cable from battery to body. All grounds from PCM and coils are lugged to front of motor for easy verification. Voltage to injectors and coils are from a relay that is fed directly from battery cable. This relay is triggered with ignition key. There is absolutely no low voltage or ground problem. I have ohmned every connection. Problem has to be one of the following:

1-software related (tune)
2-drivers in the pcm (this is 3rd pcm)
3-coils or plug wires (this is second set)
4-plugs (this is 3rd set)

I think one of my next steps is to ohmn the plug wires.

[joecar]

When you ohm the plug wires, flex them around while ohming (I'm sure you know that already...:)).

[LS1_Dragster]

I'm thinking your relay is fluttering when under load, replace the relay or come directly off your keyed ignition. Maybe even a bad ground to the relay.

Lee

[98 tigershark]

The map sensor position had to be changed too. Look at that as well. It can change things, I would call GM Performance, really.
With the 06ZO6+ Look at B2103, 2105 and finally look at the B1555 and B5113, 5112 as it shows that map affects spark. Or the VE table G/S is affected by MAP in older systems 99-04. The map sensor position has had to change even if only a little and may need adjustments for that manifold. Look at the map setting in the Diagnostics as I am almost sure that G/S is affected by Map.
Best wishes,
98 tigershark




Made another change today and seen a major improvement. I would say problem is solved but I did hear one high rpm miss. I closed the gap on the plugs from .030" to .024". I got to thinking maybe it was blowing the spark out. I know this is a non boosted engine but the heads do flow close to 400cfm. For the record plugs are NGK heat range 7. Ran it up to 6500 in high gear and it felt strong. Couldn't make anymore runs today because rain set in. I don't really understand why the improvement because I have ran this plug at the .030" gap for over 2 years. The only change is the carb style intake versus the stock LS7 intake and 48lb injectors versus 42lb.

I think I'm going to try a "cut back style" plug next. This thing is set up for a 400hp shot of nitrous so this might be needed anyway.

[LS1_Dragster]

67SS509 - Are you still running a version my tune? If I'm not mistaken, you are so references back to your old tune are not valid.

Lee

[98 tigershark]

Thats a very good point but the map sensor is mounted in a different position on the carb type manifold, Correct?. Even though a little, it is still in need of some corrections I have been told. I looked into putting one of those on my L92 427, A very cool look. But the MAP sensor is in a different Position as I recall and might need and adjustment somewhere in the tune and the Diagnostics areas. Thats what I was told. It does not take much to change things. Remember the VE needs the exact same Map to be acurate and that also goes to the G/S for the timing. This is important on all OS whether new or older!!
please let me know as I really like that setup and am curious about the Map KPA/GS and timing issues.
Good luck,
98 tigershark


67SS509 - Are you still running a version my tune? If I'm not mistaken, you are so references back to your old tune are not valid.

Lee

[LS1_Dragster]

The MAP sensor is just reading vacuum, you could have a 4 foot vacuum line feeding it! I suppose there could be a very small time variance in the vacuum reaching the sensor but I just don't see how it could ever effect the tune much. The manifold and throttle body design on the other hand will change your VE settings for sure.

I'm sure he copied over all his fuel/air tables otherwise it wouldn't run very well. When I suggested he use my tune it was mainly for the trans segment, trying to eliminate any issues with that.

[98 tigershark]

Hey LS1_Dragster,

The Map sensor is almost solely based off of the #8 Cylinder with the Carb style intake. Where as the Stock manifold it is the entire manifold. The VE is calculated with Map and thus so is the G/S for timing. So the map position in the manifold is some what critical as with the LS7 carb style intake, it is mainly reading Map on the #8 cylinder. Thats a pretty big change not to make an adjustment for.
When I looked into doing that, I was told about that issue and to be aware that it may change things, especially timing, whether SD or with MAF. It may also take awhile for the PCM to learn this new positions readings.
I am not saying that is for sure the issue here but I have not seen anything in this thread to adjust for that. If #8 is not running well and the other Cylinders are the Map could be way off and really mess with things also, just as an example.
Regards,
98 tigershark



The MAP sensor is just reading vacuum, you could have a 4 foot vacuum line feeding it! I suppose there could be a very small time variance in the vacuum reaching the sensor but I just don't see how it could ever effect the tune much. The manifold and throttle body design on the other hand will change your VE settings for sure.

I'm sure he copied over all his fuel/air tables otherwise it wouldn't run very well. When I suggested he use my tune it was mainly for the trans segment, trying to eliminate any issues with that.

[LS1_Dragster]

when your mentioning carb style intake, are your referring to mine or the original posters?

I drilled and tapped my feed to the common plenum.

I looked at the GM intake and it looks like you would have to do the same, so why would anyone drill and tap into the #8 runner?

[98 tigershark]

Does the person we are discussing in this threat have the GM LS7 Carb style intake? If so they provide the Map sensor hole on the #8 runner. Look at the 2008 GM performance parts catalog on page 293. You will see what I mean.
But that is a good question. He is using the GM LS7 Carb Intake right?
I think it is very cool that you use those type of intakes.
Let me know.
thanks,
98 tigershark


when your mentioning carb style intake, are your referring to mine or the original posters?

I drilled and tapped my feed to the common plenum.

I looked at the GM intake and it looks like you would have to do the same, so why would anyone drill and tap into the #8 runner?

[LS1_Dragster]

I just saw a picture of it and 2 things come to mind:

1) Since this is a carbureted manifold GM no doubt meant that as a brake booster port
2) If someone was to convert that to fuel injection then most likely they would drill a port in the common plenum. or use a port on the throttle body.

I really don't know how he has it set up but the worst that could happen is getting pulses of vacuum but that doesn't appear to show in the logs.

I guessing the problem is still with voltage/current to the coils. I can imagine that the relay can easily bounce the contacts, loose ground and flutter the contacts and just plain not handling the current by either being to small to handle the current, dirty contacts or just plain bad. I would ditch the relay in a heartbeat to see if it's the problem.

[98 tigershark]

I have a good connection so I will call and get back to you as I am certain the pulses you mentioned were discussed as one of the issues w/timing. Again the VE uses Map to get the G/S and any pulses can play havoc with timing.
But I will check, can we find out where the Map sensor is in this case. I would bet that it is the #8 cylinder hole. But that is a guess.
Thanks LS1_Dragster.
98 tigershark


I just saw a picture of it and 2 things come to mind:

1) Since this is a carbureted manifold GM no doubt meant that as a brake booster port
2) If someone was to convert that to fuel injection then most likely they would drill a port in the common plenum. or use a port on the throttle body.

I really don't know how he has it set up but the worst that could happen is getting pulses of vacuum but that doesn't appear to show in the logs.

I guessing the problem is still with voltage/current to the coils. I can imagine that the relay can easily bounce the contacts, loose ground and flutter the contacts and just plain not handling the current by either being to small to handle the current, dirty contacts or just plain bad. I would ditch the relay in a heartbeat to see if it's the problem.

[LS1_Dragster]

Also, as far as timing goes especially under WOT the timing for most people is set to a number such as 27 from 80-100KPA across the board, in this case timing would never ever change even if the MAP bounced all over the place as long as it bounced between 80 and 100 it would still be 27. Again, his logs showed a nice steady 24 in the first log and 27 in the second log. Since same principal applies to the fuel maps.

If I'm wrong on any of this people please chime in and let me know! I'm just talking out loud here....

[98 tigershark]

If he is using the Map hole on the GM manifold that is the problem. It fits everything including the Voltage issues. This is from GM directly. The placement of the Map is critical and again fits all of the symptoms GM or other brand. Even the WOT timing and voltages is affected so says GMPP.
Please find out as I have a permanent solution.
Thanks,
98 tigershark

[LS1_Dragster]

OK, I guess neither on of us is getting the point across!!

Any ways, here's 2 screen shots of his setup,

The first one is a run, you can clearly see the timing is fixed at 27 and you can also see the MAP is not moving around enough to mess with the timing or the VE map. The MAP does bounce around some but of course it's because the RPM's are crazy.

The second shows the timing map, clearly the timing isn't going to move anywhere at WOT but 27 degrees.

I'm not sure why your thinking the MAP is messing up the timing and/or the VE map based on the information before us? The location of the vacuum signal plays no part here. It may play a part in part throttle driving but that's not the issue.

[98 tigershark]

Look at the MAP C3003. That show that if the TPS/RPM thinks he should have 105 map. Not enough voltage with the sensor for the correct reading if it is not in the right place. It does matter! When you say WOT are you talking about PE based on RPM? Or B0105. Either way my own MAP from my logs are almost at 105 at 5300 rpms and the timing is right on, but I am using the stock L76 manifold. Do you know were the MAP sensor is located on the Carb style manifold? GMPP says it needs to be in the right spot.
98 tigershark

[LS1_Dragster]

The map reads differently at each altitude. Here in SLC, we are at 4400' or 7000' corrected. The very most we will EVER see on the MAP is 87. Take the same car to Boise and we see 90. I WILL NEVER EVER SEE 105, does this mean that my MAP sensor is bad or it's located in the wrong place? No, not at all.

Go take your car and turn the key on without starting it, this will read the MOST you will ever see at WOT because this represent 0 vacuum. Most cars will always see some vacuum at WOT so your reading will almost always read less at WOT.

Now have your buddy in a different state do the same thing, his MAP reading will reflect his altitude.

So, there is nothing wrong with his vacuum source or his map sensor!

BTW, C3003 is there to catch a bad map sensor, if you exceed or are below it will trip a DTC.

[98 tigershark]

Hey LS1_Dragster,

I really like SL City. I Live at 3800 and see 102-105 Map allot on my own car. I am confused, Is this your car or a fiend that lives by you? Anyway were is his vacuum sensor located on the manifold? please be patient with me.

98 tigershark


The map reads differently at each altitude. Here in SLC, we are at 4400' or 7000' corrected. The very most we will EVER see on the MAP is 87. Take the same car to Boise and we see 90. I WILL NEVER EVER SEE 105, does this mean that my MAP sensor is bad or it's located in the wrong place? No, not at all.

Go take your car and turn the key on without starting it, this will read the MOST you will ever see at WOT because this represent 0 vacuum. Most cars will always see some vacuum at WOT so your reading will almost always read less at WOT.

Now have your buddy in a different state do the same thing, his MAP reading will reflect his altitude.

So, there is nothing wrong with his vacuum source or his map sensor!

[LS1_Dragster]

All cars that have MAP sensors fall under this rule. If you are seeing 105 then you have something wrong!!! Go out and turn your key on without starting it and let me know what the numbers are.

These are my cars. I've done 7 in all and it jsut doesnt matter to an extent where the vacuum source is.

Look at the attached article, maybe it will explain it better then me:

[SSpdDmon]

Hey LS1_Dragster,

I really like SL City. I Live at 3800 and see 102-105 Map a lot on my own car. I am confused, Is this your car or a fiend that lives by you? Anyway were is his vacuum sensor located on the manifold? please be patient with me.

98 tigershark
This is not normal for NA cars. Do you have a vacuum leak by your sensor? It's also odd because mine pegs at 103kPa when I hit boost.

[98 tigershark]

Attached are reports that show my MAP at 100%TP
I do have a few logs at sea level at 102 map at the track actually 900ft.
98 tigershark

[LS1_Dragster]

I dont what these logs are, dont you have any logged data?

BTW, both show max MAP value at 95.

[98 tigershark]

The reports show the map were I live. But here is the deal. Were is the MAP sensor located on the manifold on #8 rail? If you know more than GMPP I am willing to listen. That was the subject, right! As to what I posted (a report from EFILIve) it shows the MAP!!!
98 tigershark


I dont what these logs are, dont you have any logged data?

BTW, both show max MAP value at 95.

[LS1_Dragster]

I think I'm in the twilight zone.........

What on earth are you trying to get across? I'm so completely lost as to what the heck your point is.

First picture 15 min 52.5 avg 95 max
Second picture 24 min 52.1 avg 95 max

So where is the 102 to 105 your talking about?

Also, AGAIN, with a 3/8 NPT hole in #8 on a CARBURETED manifold it's a BRAKE BOOSTER port!!!! When was the last time you ever saw a MAP sensor with a 3/8 NPT fitting?

BTW, did you even look at your posted logs? Are you sure these where what you wanted to upload?

Basically, I'm done with this weird conversation, lets get back on what the original posters problem is.

[67SS509]

Wow! A lot going on here today with alot of interesting points brought up.
I am running the GMMP carb style LS7 intake factory drilled for EFI. I'm using the port I thought was provided for the Map sensor. Gonna have to take a closer look at the position of it in relation to the #8 cylinder tomorrow.
I'm still using Lee's dragster base tune but with my VE map, IFR, and my timing map. My motor likes 24* timing at WOT.

Didn't get around to doing anything with scope today but did do a lot of checking plug wires. The MSD wires checked between 40-80 ohmns except for one that measured 1200 ohmns. Ran this by MSD today and they said it is a bad wire. Put it on the truck and it runs fine. Beginning to think using the truck for testing parts is not fool proof (it turns to 6800 rpm's but compression is only 10.8 to 1). Going to get another new set of wires Friday.

Checked a stock set of GM wires and they all were close to 740 ohmns. Checked the plugs I'm running and they were around 3600 ohmns. The thing that supprized me the most was a 220 ohmn resistance in the contact from wire to the plug. MSD said this was normal.

Tomorrow I'm going to take the coils off and check each one for resistance in the primary and secondary. Hoping by Saturday morning to make a run with new plugs gapped at .026", new MSD wires and a new set of coils no matter what I find with the coils tomorrow. May also relocate the MAP sensor to the plenum after some more investigating and based on comments from here. Just adding a note here...the truck has Eldebrock's new PRO FLO XL intake and they provided a port for the MAP sensor on the plenum but located near the #8 runner.

[joecar]

220 ohms... interesting.

[98 tigershark]

Look, I did admit I had the wrong map #s stated, but this was about the car in this post, tune and timing. The map affects timing very much and if the map is in the wrong placement it wont work right and it does mater were the sensor is located as to timing and voltage from the map. That was the original question if I recall. So on an LS7 GM manifold allot of people use the hole on #8 rail for the map. That causes problems as mentioned above.
Thats all, so were is the map sensor located on the car we are talking about.
Thanks,
98 tigershark

[LS1_Dragster]

Didn't you already replace the coils and wires?

[98 tigershark]

Hello 67SS509,

That is what I thought.

GMPP says that is not to be used for the MAP. Tap out a hole for the map that gets the full MAP from the plenum. That is what theysaid or else timing and voltages could be al over the place as the map is used in so many parts of the tune. The #8 location can cause pulsing and other things.
Thanks for the clarification. LS1_dragster is very good at building these I am sure but I did look into doing the CARB style manifold and they told me about that then and today on the phone.
Thanks again and let us know.
98 tigershark


Wow! A lot going on here today with alot of interesting points brought up.
I am running the GMMP carb style LS7 intake factory drilled for EFI. I'm using the port I thought was provided for the Map sensor. Gonna have to take a closer look at the position of it in relation to the #8 cylinder tomorrow.
I'm still using Lee's dragster base tune but with my VE map, IFR, and my timing map. My motor likes 24* timing at WOT.

Didn't get around to doing anything with scope today but did do a lot of checking plug wires. The MSD wires checked between 40-80 ohmns except for one that measured 1200 ohmns. Ran this by MSD today and they said it is a bad wire. Put it on the truck and it runs fine. Beginning to think using the truck for testing parts is not fool proof (it turns to 6800 rpm's but compression is only 10.8 to 1). Going to get another new set of wires Friday.

Checked a stock set of GM wires and they all were close to 740 ohmns. Checked the plugs I'm running and they were around 3600 ohmns. The thing that supprized me the most was a 220 ohmn resistance in the contact from wire to the plug. MSD said this was normal.

Tomorrow I'm going to take the coils off and check each one for resistance in the primary and secondary. Hoping by Saturday morning to make a run with new plugs gapped at .026", new MSD wires and a new set of coils no matter what I find with the coils tomorrow. May also relocate the MAP sensor to the plenum after some more investigating and based on comments from here. Just adding a note here...the truck has Eldebrock's new PRO FLO XL intake and they provided a port for the MAP sensor on the plenum but located near the #8 runner.

[67SS509]

Didn't you already replace the coils and wires?

Bought these wires new for the Camaro 2 months ago but switched them over to the truck and then back. The wires on the truck were 2 years old.

The coils are not new, just swapped over from the truck. The truck seems to be able to run fine on anything so that's why now I'm going to buy new coils for the Camaro.

[67SS509]

220 ohms... interesting.

I have always questioned the firmness of the clip to the plug on the MSD wires.

[98 tigershark]

Did you check the MAP location?
98 tigershark

[67SS509]

Did you check the MAP location?
98 tigershark

Yes, and it was in the #8 runner. I also checked the Victor Jr. I ran for a while on another engine. It was the same way and that engine ran fine. Still decided to move it on this one. There was no room on the intake itself to relocate it so I just installed it on the side of the elbow just above the carb flange. I do like it there because it will be a ton easier to get to. Probably will be Saturday before I can road test it.

[67SS509]

Found out today the coils are not a simple item. This video amazed me.

http://video.google.com/videoplay?docid=-6218245369765754251&hl=en#

and this too.. http://www.megamanual.com/seq/coils.htm

[98 tigershark]

Hey 67SS509,

That was very interesting. But There is an easier, Much cheaper and more accurate way to test your coils if you think one or two are off. Take one that you know for sure is good. Now here the the important part, are you mad at your wife or have kids? well that doesnt matter really anyway, Now have them hold a wet rag and wipe their hands clean and damp and then ask (no wait, make them) them to hold it the plug wire end when you turn over the Motor. You will instantly know if you have a good coil!! You need more kids or wifes if you want to test more!!!
Pretty smart ay!!
98 tigershark
PS I am glad you move the MAP sensor!!!




Found out today the coils are not a simple item. This video amazed me.

http://video.google.com/videoplay?docid=-6218245369765754251&hl=en#

and this too.. http://www.megamanual.com/seq/coils.htm

[98 tigershark]

Hey 67SS509

I was hoping you had resolved the tuning issue.
Let me know.
98 tigershark


I have always questioned the firmness of the clip to the plug on the MSD wires.

[67SS509]

Well, here we go again.

-new MSD wires..all checked less than 50 ohmns resistance
-new plugs gapped to .026"
-tried another set of truck coils
-moved Map sensor to elbow plenum

Still missing at WOT throttle, would not pull rpm's past 6200

started drinking again today..............

today's log attached

[Highlander]

started drinking again today..............



LOL!!!!

I have a question... does it miss? or does it STOP revving like a fuel cut. Or is it a total bog down?

[swingtan]

Again, this may have been covered....... But is the 6200 RPM limit due to the Transmission calibration being set to upshift at 6200 RPM? The spikes I see in the last log, during the WOT run appear to be at gear changes.

Simon

[67SS509]

It sounds like a ignition problem...missing and breaking up. Power level goes way down.

I don't think the trans tables have anything to do with it. PCM is commanding everything correctly, it's just not being executed in the cylinder in the right amount or at the right time.

[98 tigershark]

A power glide you said, right? WHat about traction control? You sometimes do not know if you are in reduced power mode as sometimes it does not have a DTC and did you do a vat relink after changing PCMs? What did you do with that? First I have to take a look at your tune. Let me know, I have a tune that should for a transplant LS7 with the 99-04 pcm. I too have had the 6200 rpm thing before. SO just out of curiosity can you send a pic of the setup. I am a fan of the Carb style manifold and would really like to see the finished product. There are only a few places in the tune it can be in the overall tun. As I mentioned I will take a look but let me know about the traction control And you are running a manual tranny tun w/the power glide. What temp is the cat protection set at? Most likely not the issue but it should all be set at 1279 Degrees.
Please send the pics when you are sober as I totally understand, like I said I had a 6200 RPM wall with my old setup.
Thanx and my sympathy,
98 tigershark


Well, here we go again.

-new MSD wires..all checked less than 50 ohmns resistance
-new plugs gapped to .026"
-tried another set of truck coils
-moved Map sensor to elbow plenum

Still missing at WOT throttle, would not pull rpm's past 6200

started drinking again today..............

today's log attached

[98 tigershark]

That looks like a classic theft deterrent thing( a real problem for those years and a recall for GM). Disable that and also do a VAT re-link (PCM/BCM) and it happened at the exact RPM to me? That was my problem and the cat temp. Traction control too!! What happens is at what ever time the PCM decides that there is a Problem it cuts off the fuel and you only have enough fuel left in the system to hit around 6200 RPMs. Oddly enough it can happen in 1st or 2nd. It is whenever the PCM/BCM decides. But the motor basically just stops and will restart a about 5 seconds later and recharge the fuel system but wont run well. This can be a factory issue, a Vat re-link or a theft deterrent re link issue, and if it is not those than it is a lose or bad wiring between the PCM/BCM. If it is not a wiring thing it is a quick fix!!!
I should have looked at the Video before, Sorry!!
98 tigershark

[LS1_Dragster]

Again he's using my tune. VAT is off, cat protection off, traction control off etc.

[98 tigershark]

You cant turn the VAT of or else the PCM cannot communicate with the BCM and the fuel pump will stall in a 98 Camaro. This is not a dragster and they do have things needed for the street! By the way I bet you have had toubles with Piston protection issues on some of the 411 transplants. That a guess though and not a put down. You have to do a vat relink on these cars and the PVM has to communicate with the BCM or else they all stall in 1st or 2nd gear.
I know you are very good at the retro mods and have a way cool dragster and are a very good tuner but some of the basic issues are with these 97-04 is the PCM/BCM. If you have done a PCM change in these cars (97-04) you need to do a VAT relink and check to make sure they are not in reduced power mode, not Piston Protect as that is often a mis understanding!!
Ran an 10.58 last night with a .601 Reaction time (New tires 30x335/18 Toyo R8888's). Got in a bit of trouble.
Best wishes, Hows the weather there today!!

98 tigershark


Again he's using my tune. VAT is off, cat protection off, traction control off etc.

[jetblast]

what is the low reference signal used for by the pcm guys? there are three circuits that comprise the ignition control system at least according to my 04 pcm wiring diagram. there is the power supply which as stated earlier, supplys the injectors also, the control and low reference circuits which are not shared by any other circuit. so the question has to be if the ignition and fuel are being affected. i do not recall if you had any logs showing injector pulse width along with idc, just to verify if the injectors are also loosing a signal. lastly, you won't be able to efficently t/s the problem unless you get the wiring diagram with the correct effectivity and any revisions to it, for that pcm.

[98 tigershark]

Look at page 87 in the tune.pdf regarding a new PCM or BCM.
If you are using the wiring harness from the facoty this is the deal.
regards,
98 tigershark

[jetblast]

what about the ignition control module? i can't believe my service manual mentions it and i thought they only came with distributor type hei systems. my manual states the front eng. bay as the location, but i don't think i have one, i just thought it iwas the coils themselves or the pcm itself that replaced it. so if you have one i would be replacing that in a hurry. i know for a fact that solid state iginition modules are very sensitive to heat, and often fail under high heat conditions due to the lack of dielectric gel because much of it is squeezed out during installation.

[67SS509]

This is a race only setup. No BCM and VATS is disabled. No O2 sensors and no knock sensors. No VSS. Runs in open loop speed density with no MAF. Wiring harness is a new stand alone. Only runs the injectors and coils with signals from CRK sensor, Cam sensor, TPS, IAC, ECT, IAT, and MAP sensor. One switch to a relay gives 12+volts to PCM to tell it ignition is on and feeds 12+volts to one side of all the coils and injectors.

[jetblast]

This is a race only setup. No BCM and VATS is disabled. No O2 sensors and no knock sensors. No VSS. Runs in open loop speed density with no MAF. Wiring harness is a new stand alone. Only runs the injectors and coils with signals from CRK sensor, Cam sensor, TPS, ECT, IAT, and MAP sensor. One switch to a relay gives 12+volts to PCM to tell it ignition is on and feeds 12+volts to one side of all the coils and injectors. so you don't have an icm, right?

[67SS509]

Drivers in the PCM control the injectors and coils.

[LS1_Dragster]

Correct me if I'm wrong, VAT = vehicle anti-theft?

If that's correct then by setting G1201 to 'None' then doesn't that eliminate that from the equation?

Plus when G1201 was set to PWM on my first transplant it would start for a few seconds then die, it would not run at all. If it just limited the RPM's to x amount the thieves would love that, just don't go over 5800RPM and you'll have a clean get a way!

Also, his car in my opinion is more drag then stock and even if it was dead stock VAT shouldn't matter or every transplant ever done wouldn't work either.

I'm trying to take a more simple approach and logic tells me that if VAT is off then it no longer plays a role. Also, several computers and programs later it does exactly the same thing.

And yes, your read my other posts about my Yukon acting retarded, it was indeed in limp mode because I failed to see that E1101 and E1102 were somehow set to 32 degrees and the computer thought the trans was overheating. It was not VAT.

I'm still confident his problem is supply voltage or a ground.

Lee

[jetblast]

Drivers in the PCM control the injectors and coils.

that's what i thought, can you take that pcm and install it on another ride to count it out as the culprit?, or maybe it's the location and the pcm is exposed to excessive heat! you probaly took these t/s steps already! no need to post back if you did, just trying to help. my pcm is enclose in a plastic housing and is also shilded by a heat shield, it's very close to my headers.

[67SS509]

Just added it up, there are only 21 wires to make this engine run. The handful left are for self diagnostic (OBII) and just simple grounds. Checking grounds and voltage is a simple task and I have done an overkill in this area. If that was my problem it would be fixed.

[LS1_Dragster]

I know I sound like a broken record, but eliminate the relay running the injectors and coils....

[98 tigershark]

When you changed to LS1_D tune did U do a crank relearn?(most likely)
And you are U using your B0104 and IFR settings?
Are you running 58 PSI at the regulator?
What Throttle Body? ETC? ANd is it stock LS7?
You said only changes were manifold and injectors, right! And now tune and PCM also?
No problems in the truck with the motor, right?
What are you now doing with crank pressure and valve cover breathing?
3 PCMs Now, has to be tune. Why not use the tune settings from the truck?
Less the not used items? I would put the stock manifold and injectors back in and see if that is all that has changed.
98 tigershark

[joecar]

i know i sound like a broken record, but eliminate the relay running the injectors and coils....+1.

[TFZ_Z06]

Another thing to check, water in the pcm. I once washed my car, only to have the high speed fan come on, permanently. turns out I had a teaspoonful or so of water in the processor. Blew it dry and put it back in.
Not sure how/where your pcm is mounted, but just something else to check.

[98 tigershark]

One wild though was something that happened on my Harley which has NOS.
The switch for the fuel was wired backward. Not the Nitrous, but the fuel.
It was set to come on at 4000 RPMs and every time I hit the 4000 rpm mark, it flooded and even carbon up the plugs and would then pop and snort for a while. I had to flip flop the wires on the switch and it was then fine Just a thought. Anyway that is an awesome setup and remote help is hard. I cant wait for you to get the Goblin out of this and see what it can do. Nice very nice!!
98 tigershark

[LS1_Dragster]

Another thing I just thought of...

Does this have a T-brake? If so, how high will it RPM on the T-brake? A friend had a similar problem and it was a bad converter. I had a similar problem with my 632, it spun the input shaft on the glide and it would not RPM at all.

More food for thought.

[67SS509]

Another thing I just thought of...

Does this have a T-brake? If so, how high will it RPM on the T-brake? A friend had a similar problem and it was a bad converter. I had a similar problem with my 632, it spun the input shaft on the glide and it would not RPM at all.

More food for thought.

The very first pass I ever made after building this car with the brand new ATI converter and powerglide it spun the stator. This happened in the water hole. Transbrake and converter are working good. It has a 2 step and nitrous retard but that was the first thing I disconnected with this problem.

I actually ran the car a few weeks with a 403 ci LS1 to get the suspension dialed in and the bugs worked out. It had a high rpm miss then too but not as bad as now. I just wrote it off as weak valve springs since I knew the 427 was going in. The 427 ran perfect in the truck right up to the day I pulled it. After installing it, I never drove it on the street before going to strip and just assumed I would touch up the VE table at the strip while making a few passes. First pass, missing and popping, it went 9.91 @ 137 mph n/a. Never made another pass at the strip with it, started trying to find the problem.

One reason I have been reluctant to bypass the relay is that back when I first started trouble shooting this problem I placed a jumper from the battery cable straight to the injectors, coils, and the fuel pump. I also added an extra ground wire from the coils. This was when it still had the factory harness. That pretty well ruled out connections. It's also risky because if something goes wrong or hangs up it's good bye Camaro or good bye me. I still like the Camaro a little bit and the wife likes me a little:hihi: I think

[LS1_Dragster]

How come you don't just power off your power panel without the relay? This is how I have it and it works good and is safe.

Pull the motor and take it to a dyno! Maybe the springs did give up......

[5.7ute]

Have you checked the exhaust system to rule it out? Since the engine ran fine in your other car it would have to be something that has changed between the two.
Since you have triple checked the wiring harness & power supply there isnt much left.

[67SS509]

Have you checked the exhaust system to rule it out? Since the engine ran fine in your other car it would have to be something that has changed between the two.
Since you have triple checked the wiring harness & power supply there isnt much left.

Exhaust is wide open. 3" off headers into 4" y thru 2 4" dynomax muffs and turns down before axle.

[67SS509]

Made some more tests this past weekend. Found someone with the latest Snap-On portable scan tool. It was a dual trace scope and could look at the CRK signal and the CAM signal at the same time while making a run down the road. It could also do a freeze frame. Primary voltage and wave form to the injectors were also monitered. Everything was text book perfect!
So it's not ignition and it's not fuel. No noise found anywhere.

so what the hell can it be....................:help2:

[LS1_Dragster]

valve springs......

[67SS509]

I hear ya, but it's just not valve springs. Patriot Gold springs, titanium retainers, titanium valves and Jessel Y2K shaft rockers...everthing light weight. Remember, this thing sometimes just takes off and runs like a rabbit. Bad springs would not do that and it sounds too muck like ignition. Something I tried today...eased the throttle to it and ran it up to 6500 a few times. Gave it full throttle and it misses and breaks up. It just does not make sense.

[LS1_Dragster]

Have you actually tested them? 2 times a year I always pull the covers and use the moroso tester, it takes less then 15 minutes to test every one of them. Just cause they're brand name and great parts it's still worth testing them.

Maybe run to the junk yard and pick up a harness to try? Everything imaginable has been mentioned, yet no luck. I feel real bad for you. Crate me the engine and I'll throw it in the dragster for while!

Lee

[TFZ_Z06]

Even in SD, the PCM will take the richer value of either the PE or Commanded AFR in Open Loop tables when the PE thresholds are met. This is true because I tune a little different from what the tutorial suggests by setting my OL table to 14.6:1 across the board once the engine is up to temp (i.e. all columns=14.6:1 when ECT >160*F) and my PE to the values I desire for WOT. This simulates how the car performs from the factory in closed loop operation....commanding 14.6:1 until PE kicks in.

I do exactly the same and it works great. Not sure if already stated, but I wonder if he is blowing out the plugs. I once had a supercharged car do this and I had to tighten the gap and add a better ignition. Of course now we have 8 coils, not 1.

Update:
(Nevermind, I see the poster already posted this idea. )

[67SS509]

The one thing I keep going back to more and more as the possible problem is the crank sensor and more specific the cam sensor and how they interact within the operating system. I think the wave form from each is ok but it's what the pcm is doing with these signals. I can unplug the cam sensor and the motor still cranks and runs. If I space it.030-.040" out from the .020" spec it will not fire up. Neither one will throw a DTC. I have discovered that if DTC P0102 is set it's not supposed to. Does anyone know more about this than what I have found below?

http://gearchatter.com/viewtopic9029.php?sid=b4b920fb9c0bdce83471246bc948 722a

http://gearchatter.com/viewtopic9027.php?sid=b4b920fb9c0bdce83471246bc948 722a

[jetblast]

according to my 04 service manual, the pcm will sitll be able to start the engine with the loss of a cmp sensor, but it may take a little longer because it does not know where the valve train positon is, whereas the loss of a ckp sensor will guarantee a no start condition. the 102 code should be disabled if you are running speed density, and you are right? the other aspect of the ignition control is the ic and low reference circuit, which energize the coils for a given time [dwell]. too long a time and the coils will not fire due to the current limiting feature built into them. can you swap to a new known working set of coils? you may want to lower the dwell time values first.

[jetblast]

just looked at your original tune, the dwell map table seems to be within plausible values, just a hair higher than my map table values for the region in question. the pcm relies on alt. voltage values, so i would ck. the alt. voltage output at the questioned rpm. the lower the voltage output the higher the dwell time.

[ScarabEpic22]

Dumb question but have you tried a completely different OS to see if its the OS causing problems? Weird I know but MN C5 on here tried a different E38 OS and got his truck running...

Might be worth an hour of copying tables over to see if it makes a difference.

[joecar]

Have you seen this thread: showthread.php?t=9766 (http://forum.efilive.com/showthread.php?t=9766)

[67SS509]

Have you seen this thread: showthread.php?t=9766 (http://forum.efilive.com/showthread.php?t=9766)

Read every word and was hoping for an ending that would be the answer to my problems. My reluctor was welded on by Callies.....

[joecar]

So, you have the 24x CKP reluctor, and which CMP reluctor (1x, 2x, 4x)...?

Also, have you monitored battery voltage when this happens...?

[67SS509]

So, you have the 24x CKP reluctor, and which CMP reluctor (1x, 2x, 4x)...?

Also, have you monitored battery voltage when this happens...?

Always log batt voltage.

I have the 24x reluctor on the crank. Not sure what is 1x,2x or 4x on the CMP, can you explain the difference so I can identify it. Pretty sure I have the right one as I got it from ScogginDicky as a LS2 conversion kit with the cover. Have also swapped it back to the truck and it runs fine.

I called Callies a few months ago to ask if my reluctor was tacked on because I could not remember from when I assembled it. They said back then they tacked them but have since quit. Last night I got to looking thru some pics of the build and found one of the crank. It does not look like it is tack welded. I guess a slipping reluctor is something else I need to persue now also.

[joecar]

Do you have pics of your cam sprocket...?

Is the CMP sensor located at the front of the motor (LS2 style)...?
If no, then CMP reluctor will be 1x (machined on the camshaft).
If yes, then CMP reluctor can be one of 1x, 2x, 4x (on camshaft sprocket).

If the CMP waveform looks like the blue one, then that is the 1x CMP reluctor...
come to think about it, that is what you saw from your Snap-On capture.

(I can't remember if there's a 2x).

I am not sure how the PCM knows which CMP reluctor there is.

I am not sure if this would be a problem.


For the correct CKP-to-CMP relationship/sync, see 4th pic...
if CKP reluctor walks/spins then the scope waveform would show the 4+1 CKP pulses at a different phase with the CMP step.

Edit: see red ink.

[67SS509]

This is a LS2 style motor with the LS2 CMP sensor on the front cover. I'm also running the LS2 style cam sprocket with the half moon raised area.

[67SS509]

Have you seen this thread: showthread.php?t=9766 (http://forum.efilive.com/showthread.php?t=9766)

You know I keep thinking about this one and one question keeps coming to my mind. The pcm had no way of knowing the reluctor had slipped, so it was just triggering at the wrong time. The timing being pulled had to come from the CMP sensor because of the way it works in the operating system with the CRK sensor and knew the cam was out of sync with crank.

[67SS509]

It's beginning to look more and more like the relucter wheel is moving around. This afternoon I established a mark on the front of the engine that would be for TDC on the balancer. The balancer is an ATI that is indexed the full 360*. It's really hard to be dead accurate on finding TDC with the engine in the car but to the best of my measurements with a timing light the timing is 15-20* off. When the PCM was commanding 30-35* I was seeing 45-50*. I'm going to repeat this tomorrow and if I get the same results I guess it's time to yank the engine:wallbash:

[joecar]

Does that Snap-On have dual channel capability... is it easy to capture both CKP and CMP waveforms on the same screen, and examine them for phase relationship...?

[joecar]

It's beginning to look more and more like the relucter wheel is moving around. This afternoon I established a mark on the front of the engine that would be for TDC on the balancer. The balancer is an ATI that is indexed the full 360*. It's really hard to be dead accurate on finding TDC with the engine in the car but to the best of my measurements with a timing light the timing is 15-20* off. When the PCM was commanding 30-35* I was seeing 45-50*. I'm going to repeat this tomorrow and if I get the same results I guess it's time to yank the engine:wallbash:That does read alot like the other CKP reluctor walk/spin thread.


That is a bummer...:bawl:

[5.7ute]

If it is the reluctor, why did it run fine in the other car??

[LS1_Dragster]

And why up to a certain RPM?

[5.7ute]

And why up to a certain RPM?

Exactly.
I am wondering if it is hitting an unseen safe mode for some odd reason. For instance the lack of a knock sensor input.
Have you tried wiring in the ls1 knock sensors & just removing the sensitivity?

[joecar]

Exactly.
I am wondering if it is hitting an unseen safe mode for some odd reason. For instance the lack of a knock sensor input.
Have you tried wiring in the ls1 knock sensors & just removing the sensitivity?It's worth a try.

[joecar]

Also, have you looked into the STATE pids (see STATE03).

[67SS509]

Did a little more work on verifying the timing today. Found that the ATI balancer markings have a 10* offset from TDC. I don't think the reluctor is at fault now. Did one more thing also. Reconnected the nitrous retard, dialed in 15* of retard and pulled the fuse to the solenoids. Car ran like a dog and still missed.

I appreciate everyone's help in chasing this problem but the time has come to give up. It has been months of frustration, hard work and wads of cash with no reward. I'm going to remove the engine, disassemble, inspect and freshen it up. From there I will decide the future of the Camaro. In the meantime I'm going to have some fun with the truck.

[LS1_Dragster]

I just read elsewhere a car had a similar problem and it turned out to be the converter, I know I mentioned this a while ago but I still fell it's a valid possibility....

[Highlander]

Did a little more work on verifying the timing today. Found that the ATI balancer markings have a 10* offset from TDC. I don't think the reluctor is at fault now. Did one more thing also. Reconnected the nitrous retard, dialed in 15* of retard and pulled the fuse to the solenoids. Car ran like a dog and still missed.

I appreciate everyone's help in chasing this problem but the time has come to give up. It has been months of frustration, hard work and wads of cash with no reward. I'm going to remove the engine, disassemble, inspect and freshen it up. From there I will decide the future of the Camaro. In the meantime I'm going to have some fun with the truck.

Check it up. I still think there is play in the crankshaft or something and you loose signal for whatever reason.

[joecar]

Check it up. I still think there is play in the crankshaft or something and you loose signal for whatever reason.Good point.

Check the crankshaft endplay (fore/aft thrust).

[67SS509]

Just finished putting it back together last week and ran it Sunday at the strip. Ran great! Guess what...it was crankshaft endplay. Had about .050" movement. I was too hardheaded to believe anything was wrong inside the engine because it ran great in the truck till the day I pulled it. The rear thrust journal was gone on the crank ($1200:bawl:).

Thanks again to everyone for their input on this..........:cheers:

[joecar]

You have to find to the root cause of this otherwise it will happen again.

[67SS509]

You have to find to the root cause of this otherwise it will happen again.

I'm with you on that thought. Don't know which setup did the damage but I did add .060" additional clearance on the current convertor to flex plate.

[Mr. P.]

..Guess what...it was crankshaft endplay...

WOW. Didn't see that one coming! Congrats to you on your persistence.

Mr. P. :)

[hquick]

Highlander wins the prize! Well done.

[5.7ute]

Good work.:cucumber:

[joecar]

It appears that Highlander did indeed...see posts #89 and #196...:cheers: ...good job...:banana::cucumber::banana::cucumber:

This would have shown up on the oscilloscope waveform... as the crank walks away from the CKP sensor the reluctor produces a weak signal... the waveform would have shown either a decreasing amplitude or incorrectly shaped ripples... the trick is having a good signal waveform as a reference to compare against... and a scope with a high resolution display.

The Snap-On scope display isn't quite high resolution... but maybe it did show us a few clues... see attached image (from scope display in post #86)... this is at low rpm (I calculate ~21 Hz = ~1260 rpm)... compare the waveform shapes with a known good waveform (square-tops, all same amplitude, 3rd image)... at higher rpm the amplitudes would have dropped further and the pulses would have become more mis-shapen.

[joecar]

The trick is knowing what to look for... and then it's easy...:doh2::doh2::doh2::doh2::doh2::doh2:

[jetblast]

man, had feeling that was going to be the end results. i guess running a motor on street ride is not as abusive as running it in a drag car. i wonder if that is a common failure due to high reving launches or is it just an assembly/tolerance issue from the start.

[joecar]

The converter for various reasons (ballooning, line pressure excessive, insufficient clearance, ...) it puts forward pressure on the crank bearing thrust surface causing it to wear prematurely... there are other causes.

Here's but one article: http://www.artcarr.com/page/news/1.acpp

[jetblast]

The converter for various reasons (ballooning, line pressure excessive, insufficient clearance, ...) it puts forward pressure on the crank bearing thrust surface causing it to wear prematurely... there are other causes.

Here's but one article: http://www.artcarr.com/page/news/1.acpp

thanks for the info. i wonder if a carburated/distributor type motor would have shown any signs, like the efi set-up did.

[joecar]

thanks for the info. i wonder if a carburated/distributor type motor would have shown any signs, like the efi set-up did.No signs at all... except maybe bearing metal presence in the oil.

[67SS509]

No signs at all... except maybe bearing metal presence in the oil.

and falling oil pressure!

[joecar]

and falling oil pressure!Yes, that too.

[joecar]

More info:
http://www.gnttype.org/techarea/transmission/trantsb.html
http://www.4secondsflat.com/Thrust_bearing_failures.html

[jetblast]

maybe this was the root cause!!!!!
http://www.enginebuildermag.com/Article/2058/i_replaced_a_97_ford_302_with_a_351_windsor_but_th e_thrust_bearing_failed_after_only_200_miles_what_ gives.aspx

[Highlander]

I did?????

PAY UP!!!! WITH INTEREST... 20% per month NOW!

[picnic_george]

I did?????

PAY UP!!!! WITH INTEREST... 20% per month NOW!
Statuate of limitations expires after 2 years in California and 4 years in Nevada for breech of oral contract(only saying that because that is where I live) LOLOL

[Highlander]

LOL....

Funny reading back on old things...