Starting at square 1

[1morews6]

As I stated in a previous post all the changes to my car by several shops and myself has me to a point that I need to start from scratch (live and learn) I have put a new Z06 MAF on and replaced the defective TB (bad TPS shaft) I need to know how far back to go to get this thing setup right.


99 T/A C5R427, TEA Stg3+ heads (2.10/165) 244x244 .618 112 LSA, 38# GM injectors. newly added LSX90mm intake and TB and 85mm MAF /lid. This is all in an A4 with a tight 2800 custom Stall converter. 3:73 gears.


Here is what I think I should be doing.

1. Return All my tables to stock.
2. Scale the IFR table to something near my 38# injectors (any how-tos on this out there?)
3. Check timing to see if I need to drop a few degree to avoid knock (compression 11:5:1)
4. Work on idle stop screw to get an idle and reset TPS to 0%

5. Then start working on the VE table with MAF zeroed out till I get it close then bring MAF back online and fine tune LTFTs

What else am I missing?

I have the XL tables Steve Bryant sent me to work on the VE. I need to get something to get the IFRs averaged out.
Of course I do not have a WB02 (YET!!!!)

I sure wish someone had a well tuned 427 similar to mine so I had something to compare to... but you go big and you tend to be out there all alone :roll:

If only I had been satisfied with the 500rwhp :wink:


Thanks for helping me learn the things I should have last year.

Matt

[GMPX]

If this combo has been tuned before and the engine is running well? then maybe you just need to make some minor adjustments........or is it a case of it runs really bad??.

Sounds like a wicked combo for sure, my baby 220ish 113LSA cam with A4 and 3.73's can be a handful sometimes, yet alone you with more cam and cubes!!.

'If' it were my car (others might disagree), with that sort of comp I wouldn't be running over 24 or so degrees of timing (I am basing this on 98 RON). Any idea what it is running now?. Best thing to do is to hook the scantool up and log for any knock.
Do you have a WBO2?, definately worth getting for this combo..sounds like alot of $$ have gone in to it.

My method of determining the idle stop screw position was to use the overides to move the IAC closed (0 steps), then unplug it and keep adjusting the screw until the engine is idling about 50 - 100 RPM below where you want it to (best to do this with a warm engine).
Then the IAC motor will not be sitting at 0 steps at Idle speed.
You might have to repeat this process until you find the sweet spot.

Cheers,
Ross

[1morews6]

Well, it was running ok but had a little KR, Then I swaped the TB and intake (FAST TB is JUNK!!!) I also added a SLP 85mm MAF and that turns out to be what most of the problem was. I bought a new Z06 MAF and my idle LTFTs are back to 0 to -1, but of course the 3rd FAST TB is still having issues getting back to idle RPM you have to push on it by hand to get it to fall back to the stop. I have a Nick Williams TB due here tomorrow and we will see if its better. Then I will start logging now that I am not +25% on my LTFTs :-) I was hoping to get it all lined out before the end of the month because I have a NX 200 N02 kit I want to play with :twisted: I am betting I will blow the tires off but we shall see.

[1morews6]

Ok the new TB is on and went out to do some logging, LTFTs looking pretty good at this point but when I went WOT it took off like the space shuttle but at a little over 5k RPM it was like someone pulled the plug the car fell on its face popped a few times and died. Hit the key and restarted everything is fine tried it agin with same results. I looked for DTCs and have a P0121. After reading about this code it said to look at the TPS min MAP and max MAP, there are suggestions to make changes here to 0 and 100. When I look at my tune mine are set at

TPS test Min MAP 16.2
TPS test Max MAP 19.2

When looking at my log my MAP was hitting 29.8 inHg When the car fell on its face.

I also see its in Open Loop until I lift the throttle and then it drops back to closed loop.

injectors were at 75%dc and the fuel pump is a new racetronics and pressure is holding at 68psi.

Also MAF was bouncing up and down under WOT everything else was smooth but MAF was 2930.4 Lbs/hour to 2420.4 it just went back and forth until I lost power.


Once again thanks for any help you can give.

Matt

[GMPX]

Matt,

For P0121 fault code, have a read of this thread -
http://www.efilive.com/forum/viewtopic.php?t=1179

See if that helps.

Cheers,
Ross

[1morews6]

That does not give me much hope to why the engine shut down at over 5k rpm :cry:

[GMPX]

True, but you did mention P0121.

Are you logging the Injector Duty cycle?, does that go to 0% (or close) when this problem occurs?.

Cheers,
Ross

[1morews6]

At WOT the INJDC is about 75% they fall off with everything else when it does this. I am reading some distrubing info on LS1Tech about possible Crank sensor issues. There is a mark on the end of my sensor where the wheel is/was hitting it. This was like that from the time I got the engine back. I did change the Sensor when I had the tranny out. I did a relearn on it today but I seem to still have the problem. But I cannot test because it started to rain and this car is no fun when it is wet. It only seems to happen under a load at about 5200rpm, I can hammer it from a dead stop and go all the way to 6600 (rev limmiter) and it will not do it, it only seems to happen when your pulling hard under a load. I hope my reluctor wheel is not coming apart.

[joecar]

I am reading some distrubing info on LS1Tech about possible Crank sensor issues.

Can you provide a link...
(I searched LS1Tech and got too many hits on "crank" and "sensor").

Thanks.

[1morews6]

http://www.ls1tech.com/forums/showthread.php?t=230659&highlight=crank+endplay


I am sick of this and I am going to pull the engine to deal with the reluctor wheel hitting the sensor/going out of range. I think I may as well take the C5R block out to 454 just to make me feel like I accomplished something with an engine pull. The engine always had a wierd knock at 1900rpms that could not be explained but went away higher up, I wonder if the endplay on the crank was out of spec from the start. I am going to send the entire engine to a well respected LSx shop and have them do the work and then have them break it in and dyno it before I reinstall it.


The saga continues...

[joecar]

Keep us posted.

[1morews6]

OK the engine is out and the reluctor was hitting the sensor, this all may be due to the balancer twisting the rubber our of itself (1k miles) I also had 4 lifters with broken clips (Comp R) I am told MTI (they put the first motor together) did a real crap job and I am going through the entire thing to get it all right this time. Dumping the diamond pistons for Coated JE and adding a few more Cubes :twisted: I hope to have it done in a couple more weeks. Also sent the trans out for an upgrade from Chuck (formerly of FLP) I just want to make sure it holds up to the added HP :D .

I am trying to be done in time for HotRod power tour 05.

I will let you know when its back in and ready to finish the tune.

[1morews6]

Well the engine was hit the dyno last week and on "Thier PCM" it made 627hp and 594tq :D

Will be putting it all back in the car over the next few days and hope to get on the tune of my PCM. Then comes the 175 shot of nitrous :twisted:

I guess I need to order up a WB sensor now.