Today I was driving the car, enjoying the sunny weather with the t-tops off, and noticed that even when the IAC indicator on winALDL said that the IAC was at 0 counts, I could still hear the whistle caused by the IAC being open. So when I had the car in the garage, I opened the hood and listened more carefully, and sure enough, the IAC never closes. In fact, when I removed it and briefly started the engine, it retracted -- shouldn't it extend?
The numbers for IAC on winALDL were going down, but the pintle was retracting.

Does anyone know if the IAC on the holley TB is wired differently than the ones on the GM TBs? I verified that I have the wiring between the ECU and the TB correct according to the manual.

Then, I pulled the pintle out till it would seal off the IAC, put it back in without connecting the cable, and went for a drive. The car ran better, but pretty soon I could hear the whistle again. Apparently, the vacuum pulled the pintle back enough to raise my RPM from 800 to 1500. I stuffed some plastic in the hole, and finished my drive.

Anyone have any experience with the IACs on Holleys that they can share with me???

Thanks,

John.

 

I dunno if you've already tried this, but jump A and B pins on the ALDL and click the key on. Don't start tho. When you click the key on the IAC should go to 0, or fully extend. If it doesn't then somethings not workin right.

 

There are two different IAC strategies, and possible wiring, one being flipped from the other.
So yes, depending on the code/IAC you can wind up with one running backwards.

 

Since I bought the TB on ebay, I am not even 100% sure that the IAC on it is the right one, it probably is, but I ordered a new one anyway. I'll try the ALDL jumper trick, I'll have to find the wires since I don't have a stock wiring harness set up.

 

you have a 747 ecm ? the only sure fire way i know is to manually reset it. of course the jumper wire trick could work as well. i was sure that at shut donw that ecm retracted the iac to x number of steps for restarts.

 

Yes, I think it moves it to 145 counts. Supposedly, it also moves it to zero counts before that so it knows where 145 counts is. I didn't see it move to zero when I had it removed from the TB. I need to fiddle with it some more and see what is really going on I guess.

Another curious thing I noticed is that sometimes when the engine was operating, the count would go to 145 and just stay there no matter what I did with the engine. The only way to get it to move seemed to be to shut the engine off for a while and restart it.

 

If the IAC is maxing out for no apparent reason then the VE and SA tables are still off. Don't ask me why it does this, but it does.

 

I have been running the past couple of days with the PE activation % at 99.8% so it doesn't go into PE mode. I also plugged the IAC hole so it wouldn't contribute. I now have the table at between 124 and 129 pretty much everywhere. I haven't done anything to the SA table, I guess that is next.

What procedure should I follow for tuning the SA table? Should it be pretty smoothe like the VE table? Right now, it has some pretty big bumps and valleys.