torque management issues?

[dian]

i am tuning a 99 c5 with a centri blower. using os 02020003/cos3. all was going well and i had the engine up to 6400 rpm at 0.6 bar with a smaller restrictor at 10.9 afr and 13° timing. then i put in the original restrictor and leaned out the mixture a little. now the mixture is around 11.3 until 5200 rpm at 0.6 bar (pulling stronger) but then starts wildly fluctuating between 11.3 and 12.9 until 5900 rpm (0.7 bar). ibpw seems unstable too. nothing weird in ve table as far as i can tell.

could this have to do with traction controll? would i see the reduction in spark when logging sparkadv? there is no change. i dont even know if car has torque reduction by throtle. maybe thats it?

any other ideas as to what might be happening. ignition related maybe?

frames 910 and 3050:

18926

(AD2: 0.9= 11.3 afr, 1.2= 12.6 afr)

fuel pressure is as usual btw, falling to 50 psi from 65 psi at idle (AD1).

[5.7ute]

I calculate the pcm airflow limit (512 g/sec) as being hit at frame 908 & 3043. You could try scaling the tune and see if the problem persists.

[dian]

thanks. i forgot to mention im going sd. i read about the 512g/sec limit but i thought i got rid of that with the maf. but your saying pcm limit? what exactly is "scaling the tune"?

btw, my calculations: 512g/sec correspond to 1.48g/cyl at 5200 rpm. i have hit 575 (1.66 and 17.7 ibpw) at 5200 and 0.65 boost without the restrictor before. all the values are very volatile, though.

my endevours to understand the torque limiting/cat protection/abuse management stuff have not gotten too far, but i still have the suspicion that might be comming into play somehow.

[5.7ute]

The limit applies in SD as well iirc. Easy test is to scale your VE and IFR table by the same percentage and retest. Keep an eye on the timing as it will read from a lower cell on the airmass axis.

[dian]

im i understanding right? i reduce the values in the ve table (in both tables? probably yes.) and reduce the ifr values by the same percentage? if i do this using a factor of 1.2, the pcm will read the 0.84 row in the spark table instead of the 1.00 row, for example? so i would move all values to the left by 4 rows? (a lot of typing!)

edit: not really, ill have to redo the table entierly, right?

[5.7ute]

im i understanding right? i reduce the values in the ve table (in both tables? probably yes.) and reduce the ifr values by the same percentage? if i do this using a factor of 1.2, the pcm will read the 0.80 row in the spark table instead of the 1.00 row, for example? so i would move all values to the left by 5 rows? (a lot of typing!)

edit: not really, ill have to redo the table entierly, right?
Correct. There are a lot more tables to scale especially if an auto, but the two should do for now to make sure the issue goes away.

[dian]

thanks. can you give me a hint as to what else to scale? cranking ve? what else?

[5.7ute]

I am on my phone so I can't be of much more help at the moment. Those 3 and boost VE should get you running. With the timing you should be able to copy and paste a few columns and smooth to keep the general shape.

[dian]

i see thet b5910 and b5911 depend on cylair as well. so i guess im going to scale those too.

[5.7ute]

You can. But I would verify it fixes the problem before going to all that trouble.

[dian]

i rescaled the tune by a factor of 1.3. car starts and runs o.k., a little richer than before. the problem unfortunately is not solved, its even worse. where before engine would pull cleanly up to 5200 and go lean to around 12.6, it now bogs at 4900 and leans out to 13.5. thats on the wideband (AD2). the narrowbands stay rich btw, above 0.9v. frame 2400. actually it now starts leaning out at 4500. fp again is as always. i went off the throttle immediately, because i dont want to fry the engine.

any thoughts appreciated.

18942

[joecar]

Can you post your tune file...

[joecar]

Which wideband do you have...?

[dian]

tune file:

18948

file before rescaling:

18949

file and log with run to 6200 at 0.6 bar (frame 7400) using the smaller restrictor:

18950

18947

im afraid to do further experiments until i understand whats going on.

im using the ecotrons wideband on port ad2. i still have to figure out where to go to create calc pids or how to connect the serial port.

http://www.ecotrons.com/files/ALM-Gauge%20Manual.pdf

i could log with their software also, but was so far getting sensible result as is.

the road might still have been a little wet whan it bogged at 4900, so maybe this is somehow traction/torque related after all?

[5.7ute]

Cable or Electronic throttle? Spark plug gap?

[joecar]

Hmmm, it has an RS-232 serial comms output...

[joecar]

In that doc I don't see a spec that converts AFR to V...?

[dian]

throttle is electronic. if pcm will use throttle to reduce torque i have no idea. i believe trottle management is disabled now, but perhaps not? can i bee seing a rich condition from misfire due to detarded spark where it looks lean? doesnt feel like it, but sometimes you dont feel much at these rpm.

info on the voltage function here (p.8):

http://www.ecotrons.com/files/ALM%20GUI%20Manual.pdf

[joecar]

page 8: Lambda = Volt * 0.30 + 0.50

we can make a calc pid for this...

[dian]

thanks, can i make it too? i just dont know where. i would probably know how. once i found some tutorial in v8, lost it and never saw it again.

never mind, this is not the issue, obviously if i tune to 0.9v (and i know 0.95 is 2% less fuel and 0.85 is 2.5% more) or to 11.3 afr or 0.77 lambda doesnt matter. and how accurate the values are in the end only god or the guys with lab equipment know i guess.

if i only knew my torque management is definitely disabled.

[johnv]

i am tuning a 99 c5 with a centri blower. using os 02020003/cos3. all was going well and i had the engine up to 6400 rpm at 0.6 bar with a smaller restrictor at 10.9 afr and 13° timing. then i put in the original restrictor and leaned out the mixture a little. now the mixture is around 11.3 until 5200 rpm at 0.6 bar (pulling stronger) but then starts wildly fluctuating between 11.3 and 12.9 until 5900 rpm (0.7 bar). ibpw seems unstable too. nothing weird in ve table as far as i can tell.

could this have to do with traction controll? would i see the reduction in spark when logging sparkadv? there is no change. i dont even know if car has torque reduction by throtle. maybe thats it?

any other ideas as to what might be happening. ignition related maybe?

frames 910 and 3050:

18926

(AD2: 0.9= 11.3 afr, 1.2= 12.6 afr)

fuel pressure is as usual btw, falling to 50 psi from 65 psi at idle (AD1).

Fuel pressure should should not drop at all, I suspect you have reached the limit of your fuel system.

[joecar]

thanks, can i make it too? i just dont know where. i would probably know how. once i found some tutorial in v8, lost it and never saw it again.

never mind, this is not the issue, obviously if i tune to 0.9v (and i know 0.95 is 2% less fuel and 0.85 is 2.5% more) or to 11.3 afr or 0.77 lambda doesnt matter. and how accurate the values are in the end only god or the guys with lab equipment know i guess.

if i only knew my torque management is definitely disabled.I can show you how later.

In the meantime you have the voltage-lambda mapping in your mind already.

[joecar]

+1 I agree with johnv

( if your FPR is un-referenced then rail pressure should stay static +/-1 psi )
( if your FPR is manifold-referenced then rail pressure varies with MAP, which in your log AD1 has no correlation to MAP )

[dian]

i am disapointed that the lingenfelter pump drops off so much. i will probably get the racetronix harness. but fp drops in a consistent maner so it should not be causing what im experiencing.

btw, there probably is no way to logg the pump voltage from the pcm, right? am asking because of b4002. gm.volts is the battery voltage, right? but then this table doesnt make any sence.

[5.7ute]

Plug gaps ?
Also not sure on the 98's but that throttle position pid doesn't look right for ETC. You will need to log the actual throttle blade position to see if an ETC torque limit is in play.

[dian]

good idea on the throttle blade. but what pid do i logg? gm.tp? sae.tp-b/c? gm.etctp1/2?

how can you get some info on the pids? when i rightclick "more info" doesnt work.

[5.7ute]

Like I said I have no experience with the 98 pcm. It should be obvious though if you connect to the vehicle, validate the pids and test. ETCTP I would say is what you need.

[dian]

thanks. it a 99 btw.

[joecar]

Yes, for DBW log the pid GM.ETCTP.

[dian]

i put in the smaller restrictor and made two passes on the resized tune, one to 6200. no problems (except mixture being on the rich side). 155 map, 14.5 ibpw. so at least i know i havent killed the engine yet.

so original restrictor goes back in, but its rainning so further experiments have to wait.

ibpw was at 14.5 (4950) and 15.1 (5300) when engine would bog before. i have been up to 17.5 without restrictor at 5200.

btw, could someone have a look at my dashboad C? how do i format that properly. resize to dashboard does nothing. its too wide.

[joecar]

Post some screenshots (SHIFT-PRTSCRN, save to .png or .jpg file, post file here) of your dashboard.

[dian]

o.k., i see something is not working with my dashboard c, it even doesnt come up in the logs i posted. or can you see it?

[dian]

sanity check on injdc (81%):

63 lbs/h @ 43.5 psi = 69 lbs/h @ 52 psi
69 x 8 = 552 lbs/h
552/0.6 (bsfc) = 920 hp
920 x 0.8 = 736 hp

i am probably making:

345 hp x 1.7 = 586 hp

where does all that fuel go? or is injdc not a measured but some calculated value?

[statesman]

Under boost there's more air pressure working against the fuel flow... you have to subtract the boost pressure from your rail pressure and then recalculate your fuel flow rate.

[joecar]

o.k., i see something is not working with my dashboard c, it even doesnt come up in the logs i posted. or can you see it?The dashboards are separate from the logs...

while hovering over the dashboard, look at the right side of the status bar, what dash filename does it say...?

[dian]

right, stupid me:

52-10=42 psi
63x8=504
504/0.6=840
840x0.8=672

still a difference of 100 hp. bsfc would be 0.69. o.k., considering a dead time of the injectors of 1 ms (1/16=6%) bsfc is 0.65. getting closer.

[dian]

so i finally managed to get the screenshot in here:

18963

the grafics are too wide and the cursor doesnt line up.

o.k., you cant see much, i will try again.

18966

18967

thats the best i can do, sorry.

[joecar]

What is this...?


right, stupid me:

52-10=42 psi
63x8=504
504/0.6=840
840x0.8=672

still a difference of 100 hp. bsfc would be 0.69. o.k., considering a dead time of the injectors of 1 ms (1/16=6%) bsfc is 0.65. getting closer.

[dian]

thats a correction of post 33 after statesman pointed out the mistake.

so the bogging problem is solved. ute was right, it was the gap.

why do i have to be such a smartass. i figured that since my single coil jeep can fire a 1.6 mm gap without problems, the c5 would handle 1.3 mm on the platinum plugs at this boost level. well, i was wrong, i put in the ngk r tr6 gapped at 1.0 mm that came with the kit and the engine pulled to 6200 very well. i flashed in the non-rescaled tune and everything was fine.

now i even get a tire chirp between 5000 and 5500 in second gear. that makes me believe that any torque management is definitely disabled in the tune. dyncylair is 1.55 max, so i believe this ecu has no 512 g/sec limit. is that possible?

with this gap i can probably increase timing by two points.

[joecar]

Ah...

( I'm trying to get back into the grove after a few days, think of it as a sanity check )

you have 10 psi of boost on top of BARO...?
is your FPR unreferenced...?
is your FPR is set to 52 psi...?

[joecar]

so i finally managed to get the screenshot in here:

18963

the grafics are too wide and the cursor doesnt line up.

o.k., you cant see much, i will try again.

18966

18967

thats the best i can do, sorry.Uh Oh, looks like someone messed with the widths of the charts... can you post that log file, I'll make you a nice set of charts that line up properly.

[joecar]

What is on EXT.AD1 and EXT.AD2...?

[joecar]

Unzip the attached file and move the contents to the folder Documents\EFILive\V7.5\VDash

and then start the scantool and go Edit->Properties->Startup and checkmark Always Load Dashboard File, and specifiy file LS1B-0220.vdb, click Ok.

Then on Dash B, click the open dashboard button (looks like 3 folders opening) and specify the same file.

I didn't configure Dash A since the charts are way more useful than the gauges, bu we can do Dash A later if you wish.