When I start the car, it idles ok in open loop, but it dies as soon as I put it into gear. Park/neutral idle is 800, drive is 775. It acts like the injectors shut off. What can I change in TunerCat to give it more fuel to keep it from dying? I've tried adding to the Open Loop tables 100% and there's no difference. Is there another table not defined in TunerCat? It will die when its warm or cold. Once it goes into closed loop its much better, but it will still die once in a while.

GregW, Glenn, Grumpy, Tim, any ideas? Thank you.


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1991 Camaro Z28
5.7L 5-Speed (originally 305)
317 RWHP, 418 RWTQ
13.23 @ 107.62 MPH
Southern California
Member: SoCal 3rd Gen F-Bodies
Member: SoCal F-Bodies
-=ICON Motorsports=-

 

I just added 10 to the Open Loop Fuel/Air Ratio %Change vs Load and 3 to the %Change vs Coolant Temp, and the car acted like it got leaner! That is a percentage change right? Higher numbers means more fuel added?

 

What is the IAC motor doing when it dies? I'm guessing it's stalling due to lack of air, especially if the IAC motor can't compensate enough if it's maxing out when trying to recover. Yes, the higher the number, the more fuel is added. Did you raise the stall saver speeds?

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Greg Westphal
'87 IROC 355TPI/A4

 

Not to sound stupid... but what are you doing running ARAP code with a 730 ECM ? Isn't your 91 a speed density system ??

 

He is working on a friends MAF camaro..

 

I had changed the stall saver to higher values but set them back to stock thinking it was a problem. The IAC values are good, in the 50 range. The injector pulse width is about 1.9, and drops to 1.1 just before the car stalls. The funny thing is this stalling doesnt seem to happen with his 88 Hypertech chip. Its either something in the stock ARAP or something I've changed. Idle is 800 in park and 775 in gear. There is no warning or anything before it stalls, its as if the computer just shuts off the fuel for whatever reason.

Here is the previous post:
https://www.thirdgen.org/messgboard/...ML/002034.html

 

What are the IAC counts in Drive compared to Park? What is the airflow reading doing when it starts to stall? I have a 150 rpm spread between them to keep the IAC counts the same. With a lower idle speed decrease from Park to Drive, the IAC motor would have to ramp up to keep from stalling the engine. I'm guessing the injector pulse width is dropping due to a sudden decrease in airflow before the IAC tries to compensate and ramp the idle speed back up (which would've dropped due to the increased load on the engine when the tranny is put into Drive). Just a shot in the dark...

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Greg Westphal
'87 IROC 355TPI/A4

 

I have a 25 RPM difference in idle between drive and park. I thought it was better to keep them close to each other?? The IAC is at 52 in park and 65 in drive. It shoots up to 100 like its supposed to when the engine tries to stall, but its not quick enough.

Surprisingly, I keep messing with the Open Loop tables, and it got better as I leaned them out. It stalls a lot less now, but it will still do it if you start it up and then immediately put it into drive. If I let it sit for 30 seconds first and stabilize, then it wont stall.

There's still a bit of an off-idle stumble, tho...

 

You could keep the 2 idle speeds close together with a really loose converter that doesn't put much of a load on the engine in Drive, but not with a stock or mild converter. The IAC positions aren't that far apart, but going up to 100 and still not catching the motor indicates that it's suffering from a lack of airflow when the tranny is dropped into drive. Not sure why leaning it out helped...

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Greg Westphal
'87 IROC 355TPI/A4