E40: Start issues

[MMGT1]

Just cant get this one to start without hunting. Have tried timing as high as 26* and as low as 16*, airflow up, airflow down, we have tried everything and just cant get the hunt to settle. There is obviously a start up timer and decay that I cannot find. As soon as what I am thinking is a decay timer runs down, it settles right down. I am attaching the best we have managed to get out of it so far. If you need any info please let me know. 60Lb injectors scaled into tune so you know from the hop here.

BoostedLS2_08.hptscan start 8.hpl

[MMGT1]

You need to ignore the wideband as it is resetting every time he starts the vehicle.... so it is the warm up cycle you are seeing in that scan

[MStefak]

Hmm am i missing the entire thread?

[MStefak]

Is this the same car you were working on a couple weeks ago ?

[MMGT1]

Hey bud, yea one in the same. We got it to fire up every time, then as soon as, what i assume is a run down timer expires, it runs beautifully. I'm trying to find if there is a way to speed this decay up and have it shift to normal running conditions sooner. There has to be something in there we can attack and fix this but I am at a complete loss on how we can speed this process up!

[MMGT1]

Is this something that the support team would attempt to help with or are we limited to asking on the forums here? I'm thinking that support is only for the program uses and not something like this right?

[MStefak]

Yea they typically don't help with the tuning.

it might also be when it hits closed loop. Check see if it's on open or closed loop.

If it's in open loop then when the pcm decides to go into closed loop it straightens out its your Open Loop Fueling table.

It sounds like a lean condition . In the older pcms you used to be able to adjust "after start enrichment " . Was a frigging pain to dial in but would make aworld of ddifference when it was.

[MMGT1]

No closed loop, OL only in it. I think the issue is part of a start up decay rate. Just cant find what table would dictate the decay of the start tables. I do think that is what would fix this, but just a guess at this point

[DSteck]

Why did you set the desired idle speed to the same speed at all temperatures? Your base running airflow is WAY higher than it needs to be. Too much will actually cause the throttle to close. Your VE table needs work, too. I'm also betting your MAP sensor data is slightly off (should be 200/8 if you're using the normal GM 2-bar). Personally, I'd say start over from scratch after looking through. Your spark adders for idle control should be returned to stock. You're also clipping yourself at 24* of timing by having that in your main spark table (even with underspeed adders, timing will never go over 24*).

All of that aside, the problem lies in how you're failing the MAF. It's actually not failing into SD right away. Exactly three seconds after the engine is considered to be attempting to run, your cylinder airmass is cutting in half (which is when it is failing into SD). That three seconds is the exact time that your configuration takes to fail into SD.

Use the config I attached and log it. There's a lot missing from your log.

[MMGT1]

Thanks for looking at this Steck. The idle speed was not my choice bud, I had set it to fire up at a higher RPM and fall back to 875. The owner says it hits too hard on the trans when shifted to drive cold. A lot f this tune is not me, I have been slowly undoing what was done before I got involved in it. We lowered the base airflow to 2 grams over a stock LS2 and it would not fire up. We added a gram at a time until it would fire. I will find out which 2-bar he is running, another piece I have not touched in this tune. I will get a log of your config with your recommendations implemented. Closest thing I can find to a stock file for this, since the auto in it is a semi-auto and will only shift when you manually shift it, is a 2005 Holden manual in the repository. A VSS sensor was added to the tail stock to get a signal to the PCM in it as well if that helps you any

[MMGT1]

Got him to this right now, still working on it:
BoostedLS2_13.hpt

9 is what we started with tonight

[MMGT1]

BoostedLS2_13.hptscan 05.hplE40_2Bar.cfg

Had to add to histo 11 and 12 to get it to line up with his PCM. Yours are more detailed than his are. But, that is where it is right now

[SultanHassanMasTuning]

as mentioned you need to fail MAF. with switch on open your scanner and find MAF state: should be Failed

[MMGT1]

Failed MAF.jpg

Did we get it right this time guys?

[MStefak]

Did you set the disable and enable to like 300 rpm ?

Sorry I still can't view tunes since I'm. On my phone no laptop up here.

[MMGT1]

There is a test enable that we dropped to 5 RPM hoping the MAF fails as soon as it begins to turn over. There is a timer to begin the test that is set to .1 sec and both the high and low thresholds for the test are set to a value of 1 now. In a couple of hours Ill be able to test it but thought Id ask if I got it right before we go at it tonight. This E40 is unlike anything I've ever gotten into, and is seriously making me loose a lot of sleep. This has become an obsession to figure this dam ECM out!!!

[MStefak]

Then I'd say your good to go.

[MMGT1]

Had to call a spade a spade and walk away from it. I cannot get it to settle for him until well after start now, so I had to suggest he finds someone that knows the 40. I tried everything and it will not come in line for me. Making those changes made it worse

[MStefak]

If your just mail tuning it that can be a pain in the ass , but it seems like a lean or rich issue after startup

[MMGT1]

That's exactly what is gong on. I've tried to help a much as I could. The wall I've hit is not being able to keep the wideband from cycling when he starts. He's letting it cycle and then as soon as he engages the starter it's throwing the NTK into warm up cycle for 20 seconds. So, AFR at start is nothing more than a guess and its completely screwed us. The MAF is still not failing until 3 seconds after start so that just ended me on it