bigken

iTrader: (8)

Ever since I had my Trans Am tuned for the converter I started having problems with the idle air control. I have taken it to a shop to be fixed and now I am not getting any codes for the IAC but when the car is cold the RPM's surge up and down and will constantly stall out until they finally catch. Even then for the first few minutes will driving it will stall out once or twice. When the car is warm it really doesnt do it, but if it has been sitting for more than an hr or so it will. I do not really drive the car all that much but no matter how many times I take this to get fixed I am having the same problem, does anybody know what may be causing this? Does this need a re-tune? I never had this problem before the converter.
thanks for any help!

NoGo

iTrader: (2)

Just sounds like the cold-start tuning is off.

Is the car cammed?

bigken

iTrader: (8)

Yes it has a comp 566, 568 lift cam, as well as Partiot stage 2 heads. Before I installed the converter I did not have the issue and when I got the tune just for the converter I started having problems with IAC.

NoGo

iTrader: (2)

My guess is it isn't the IAC, it is the a/f ratio. Perhaps your new converter is looser than stock and doesn't load the engine as much - so any idiosynchrasies in your idle tune are starting to show up?

What makes you say it is the IAC?

bigken

iTrader: (8)

Well after I had the car tuned for the converter the next day it threw a code for the IAC. I brought it back the following weekend and left it with the tuner, now since I picked it back up I have had these issues. I have brought it back since but the problem is the car is warm and he said it doesnt show anything abnormal. Even letting the car cool down for a little over an hour didnt help as when it is warm it fires up and holds. The car is fine when it is warm but I don't even want to drive the car when it stalls out 7 or 8 times just getting out of the garage. There is obviously something wrong in the tune but the shop who did the converter tune said the tune was fine and didnt want to charge me for a re tune when he couldnt improve anything????
I am at a loss

BlueThunder2

iTrader: (3)

Yes, it needs a proper tune. Once the afr is set properly, including start up table, it won't do it any more. Especially since your cam is not extremely aggressive.

However, to get you by until you can get a retune, there is a "star" bolt on your throttle body. (It might be upside down) This bolt is the resting point of your throttle linkage. If it is upside down, pull your throttle body off (3 10 mm bolts, two cooling hoses, and your intake lid/maf/hose assy), get a torx bit screw driver or wrench and take the bolt out. Then, put the head of the bolt on the top side of the throttle linkage rest. Then tighten it almost all the way down. Next, reintall the throttle body, cooling lines, maf, hoses and lid. (takes about 15 minutes to do all of this) Now, your idle is manually adjustable. Use it like you would adjusting a carberator. Loosen it to allow more air, tighten it for less. There is a sweet spot for your car. Find it, and your car should stop stalling until you can get it tuned.

NoGo

iTrader: (2)

Did they change the IAC?

There isn't a whole hell of alot of stuff that will throw a bad IAC code - a bad IAC being one of them. A common issue is a shop playing with the TB bump stop or drill a hole in the TB to try and get the car to idle. If they open the TB too much it can cause an IAC to throw.

Have you tried swapping the IAC just to rule it out?

bigken

iTrader: (8)

I will give it a shot I will try anything at this point because I dont even want to drive the car with how it is running.

BlueThunder2

iTrader: (3)

Just remember to make small adjustments. Too much in either direction and it will mess up your idle. (ie idle too high or surge or cut off)

Remember though, this should just be considered as a temp fix. When properly tuned, with your set up, it shouldn't require the throttle blade to be open too much at all in order to idle.

bigken

iTrader: (8)

Seeing as how it is not my DD I may just get it re tuned instead of messing with it at all. I do not drive it often, but when I do I don't want it to be a chore just to get it out of the garage.
Thanks

white01ss

iTrader: (37)

Have your tuner dial down the idle learning tables in the 20-60 RPM range. May need to completely zero out the 20-40 range as your cam will normally fluctuate that much. That should eliminate the hunting idle.