when you rev it up high then take your foot off the gas abruptly and let the revs drop quickly, it stalls. otherwise runs and idles pretty well. what needs to be tweaked to remedy this?

prominator, modified arap, $6e, pretty close to 128blm all the way up and down but slightly lean at idle.

 

Check your IAC steps and maybe you need to adjust(open) the TB blades little ...I adjust my blades so I get around 15steps on IAC at des. idle speed.

SA and DFCO can also make a diff..........

/N.

 

You say "DFCO can also make a diff..........".

What does DFCO do? Can you elaborate?

 

Decel Fuel Cut Of, shuts of fuel when you let go of the gas.....

/N.

 

What GTA34 said ... except more specific. You want to achieve ZERO iac steps with the car fully warm and in drive!

Tim

 

nice info. thanks guys.

 

well, i already had 15 iac counts at idle. i'm thinking i can increase the rpm that the dfco and decel enlean disables. what do you think?

 

What about ZERO IAC steps at idle fully warm AND IN DRIVE.

Tim

 

Also, I am finding the ARAP bin has some other things that make it "troublesome" on a heavily modified engine. I finally gave up on the ARAP and went back to the AUJN bin (and transferred all my spark and fueling tables from the ARAP to AUJN).

That solved a lot of quirks that seem to exist in the ARAP bin.

 

I just wish there was a manual tranny version of S_AUJP....

I've been thinking about setting up a stock AXYC and then trying to make essentially the same changes, but doubt that would satisfy the motors in manual applications.

Anyone know what would be required for this? Then I could paste my own spark, VE, startup, etc. tables into it....



NEVER MIND.... I just realized this sounded like prom begging, and I'm not about to do that.... edited 3/10/05

 

Do you have a functional VSS connected?

This may be an apples to oranges comparison, but I found that my TPI Suburban conversion (stock engine) would stall very frequently when rapidly decelerating. I was told by various sources that without a VSS, the ECM does not "know" the vehicle is decelerating. My BLM would drop to like 114 when coming to a stop, then quickly climb back to normal. This seems to suggest that the DFCO was not coming into effect.

Originally I did not have a VSS because the Surbuban pumps out 128,000 ppm. Well, long story short, I installed a Dakota Digital buffer and fed the 7727 ECM with 4000 ppm and now my problems have all but disappeared. Everything about the engine is smoother now, including the idle.

Maybe the lack of VSS on a lighter vehicle would not cause or contribute to your problem; but this was just a thought. Ed

 

VSS is hooked up and functioning

 

Trax, could you explain why there should be zero iac steps warm/in drive ?

 

Zero IAC steps when warm and in DRIVE will surely make the idle speed too high when in Park or Nuetral. Zero in P/N and maintaining proper idle speed is about all you could ever need, but risk getting the IAC stuck shut (not a big risk, just mentioning it).

I had the same problem on my car and don't remember if I ever fixed it. I think the problem went away with a new ECU though (haven't been in the US for a few months).

 

Some people don't have experience working on cars with big cams such that when you place the car into drive that the extra load from the driveline being 'hooked up' is enough to stall the car. On highly modified vehicles with stalling problems this is the first thing I suggest. It has fixed a couple vehicles that I have worked with. It is also EXTREMELY helpful in situations when running a driveline that sucks up more power than a 700R4 ... like a TH400.

Tim

 

i assume this is what you did on your iroc since it had a pretty big cam. what effect did it have on your idle? what was your idle speed at op temp? i've heard that constantly bottoming out your iac can prematurely kill it. have you discovered otherwise?

 

Adjust your TB blades to achieve zero IAC counts like TRAXION said and that will take away all that stall after stabbing the gas. But be sure that the car is in operating temp