big problems with cold start using ID850 and stoic trick

[rob_mac]

Hi guys

Having a massive problem here with an engine setup using ID850 injectors on an early model e38 pcm and getting around the 63lb injector coded limit

Have tried tuning the car numerous ways, but run into the same hurdle regardless

The car will tune up, drive and behave perfectly at all times EXCEPT initial cold start and post start enrichment

IF you can get the car started and to stay alive past the first 30 seconds or so she is fine - but this first part is the problem. Warm, or even semi warm she is perfect

My latest attempt has involved trying the "stoich" trick, but doubling stoic far and halving injector flow rate. Also tried, on advice from hptau, o try tuning it and just "wear" the injector coded limit in the ve table - which surprisingly worked out ok despite the same cold start issue I'm having using other methods

One of the biggest issues seems noticed when scanning is that getting the car to kick and fire isn't the big issue, but once she does she will want to die. If you tap the throttle etc to try to keep her alive, the injection time will max out to some ridiculous number like 200-300ms +, flood the thing, and kill the car

The car only really dies when this happens, but for the life of me can't work out why it is doing it

Mods are

20007 Australian VE CLUBSPORT
LSX376 crate engine
233/238 lsa 114 camshaft
YELLA TERRA 3.4L whipple supercharger kit
upgraded fuel pump (fuel system is still return less)
ID850 injectors


a few variations of tune file and log of the injection time going spastic post crank attached

any thoughts here guys?

jorge_fuckedupstart2.hpljorge_weirdoncrank.hplBARCODE_veclubby_lsx376m6_whipple34_id850_tune_lowboost_14psi.hptBARCODE_veclubby_lsx376m6_whipple34_id850_tune_lowboost_14psi_stoichtrick.hpt

[realcanuk]

Only thing I see right away is your startup airflow seems very high compared to what I normally see. I would start by trying that with stock numbers and see if it helps. Then go from there.

[rob_mac]

i have only done this for testing to ensure she kicks and rise to stay alive as long as possible - because as soon as you apply any throttle, the injections time goes through the roof and kills the car so to speak

[Niemer]

I have been having issues on cold start with ID850s and the IFR/Stoich trick. Not nearly as bad as what you are experiencing, but before it gets up to temp and as I roll to a stop the mix goes super lean and the car really pushes and wants to die. I've tried messing with a bunch of stuff, including transients, without any luck.

One thing that happens when you do this flow rate workaround is that the IVTs get all out of whack, I'm not sure what the difference is between stock and scaled is. This probably isn't much help, but hopefully knowing that someone else is having similar issues offers some consolation.

[realcanuk]

I don't know the problem but I have no problem with cold starts using the same setup.