IAC question

[77tech9]

I got a red 93 chip and tryed it instead of my usual 92 Thrasher chip and had good track results but bad driving results.

I think my tuning is wrong for my IAC, i set it so that it would be 20-25 at idle in park, but sometimes when i accel fast and depress brake it will die or come to a really low idle for a few seconds. Sometimes it will go far enough to actaully quit running. At times after driving I will check IAC and it will be around 35 or so, this is checking at closed loop after driving.

Under boost there is no stumble or anything and it runs hard. My fuel pressure is 43 with line off. I do have a small header crack that is going to be fixed soon, but I dont think it would cause this. The thrasher chip runs fine and no stalling.

 

[scottyb]

I haven't had issues when switching between those same 2 chips, except the RA is sometimes a cold start stumble.

I believe that a good cleaning on the throttle body and an IAC setting ~ 10-15 makes the smoothest transition. How many screens in the MAF?

 

[77tech9]

I was setting my IAC around 25, i'll try 10-15 and see how it works.

There are both screens in the maf, i'm not sure if this is causing a problem or not.

 

[scottyb]

There has been some debate about the screens. Red Armstrong told me to remove one screen, and it's been that way for over 2 years. It still is a bit nasty on cold start.

Have you cleaned your TB and IAC, etc.? I noticed a remarkable difference in idle, tip-in, and overall drivability when I did mine. This is also when I started setting the IAC at ~10.

 

[77tech9]

I've been messing with it all day, trying the IAC at 10, 15, etc same thing.

Took off the maf, cleaned it, etc. I cleaned the TB, but I havn't really taken off the IAC to clean it, I might do that today and see what happens. I was told to make my FP to 43, and i noticed my BLMs are 138 at idle.

 

[77tech9]

Also something weird, sometimes my IAC at idle will goto 58 or some weird number, but if i shut off car and turn back on it will drop to 20...

 

[scottyb]

High BLM indicates vac leak. If you have one, then IAC adjustments may drive you nuts.

 

[MistaScott]

or exhaust leak. Mine was a cracked header. 138 is not necessarily a leak unless it is pegged.

 

[77tech9]

I think the header is my problem, I just can't keep them filled

I should call poston and see if I can get a new set instead of keep fixing these.

Thanks for the replys. My BLMs are fine crusing and car runs strong. It's just stopping and idling is the problem, but it will be ok as soon as I fix the header (I hope).

 

[big black..dong]

cracked headers.. ..??

got cracked headers??
email me btelotte@hotail.com
I'll weld em, plenty of experiance.
this is not a do it yourselfer!


Bill