MS3 Mini - Very low AFRs/Stalling after heat soak
 

Car is a 2001 NBFL 1.6L


Long story short, the car will run, drive & idle perfectly for about an hour of driving.

After that when coming to a stop the rpms drop super low, closed loop idle most of the times will save the car from stalling but the AFRs during the ordial are super low ~10,5.

If it stalls the car has a very hard time starting unless you press gas, then its not certain if it will keep running or die.

Letting the car sit and cool down for 15-20 minutes, starts to behave normally again.


Im new to tuning, but i've done my research before posting, i hope someone can point me to the right direction!

I've checked the obvious but i cant find the culprit!


Attached is the tune & logs of the weird behavior


Thanks guys

I don't see a tune or log attached. My guess is your MAT Air Density Table is adding too much fuel, changing the entire table to be 100 is something I would recommend until your VE table is tuned.

I've attached the files again, it should be ok now!
Initially that was my suspicion too, but unfortunately MAT Air Density Table seems to be ok. I've looked at the Fuel Calculations Summary but i cant seem to pinpoint whats wrong.

Your car is set to use the Closed Loop Idle Initial Value table however all entries inside of the table are 0

This will cause the car to stall as the valve closes whenever it tries to enter closed loop idle & send the IAC 0% duty

Also having the closed loop idle setting PID gain slider at 2k is pretty high, running the same PID settings as you I have it set at 500. Around 1k I had issues with the car seeking its target idle speed too hard and stalling even with a tuned closed loop idle table.

Hey man, thanks I will revisit the Close Loop settings. Do you think this is the reason the car behaves like this? Until it gets heat soaked it seems to run just fine

Almost 100% yes, a way to confirm this would be to check and see if the car ever enters closed loop idle when it is warming up, I suspect some settings are preventing it from entering closed loop til the car is warmer than usual. The logs indicated nothing except the valve IAC Duty % dropping a ton, which I can only assume is due to a zero'd out closed loop idle table.

I would be surprised if the car didn't stall when it tried to enter closed loop idle with the current setup

I will do a full log run tomorrow including cold start etc and ill try to fix the closed loop settings! Thanks for the guidance! I will report back tomorrow.

why are you using 2 spark maps?

I have not touched the Ignition Settings apart from the basics! this is how it was from the basemap.
How can i disable the second table? <- Ignore i found it through the manual

Here is a new set of logs
Unfortunately the problem still persists

1. cold start and idle until hot without any changes to the tune, no throttle, no ac etc
2. first drive with closed loop initial values table filled (experimented with the values as i went) everything seemed to be ok!
3. second drive the problem started to appear again, check the logs and you will see that the AFRs keep dropping and at the second half of the drive the RPMs during throttle lift/coasting/stopping drop very low
4. third failed start attempt after stall.

I also attached the latest tune for comparison.

Thanks guys!

Any ideas anyone?