Hey guys, i just set the min air screw on my tbi to try and fix the idle issues. Well i followed the instructions from over at 454ss.com and seemed to work good. Except when i start my truck it idles at around 1400rpm then it will gradually get down to 1000rpm, when i put it in gear it will get usually get down to 650rpm with 0 iac counts, and when i put it back in park it idles at 800rpm with about 0-5 iac counts. However when i shut the truck off and restart immediately it jumps right back to 1300rpm and stays ther until i put the truck in drive is this what it is supposed to do, or should it be idling right back at 650.
Please help.

 

If you set the IAC when the engine was cold, that can make it not idle correctly at all temps. I ran into this with my SS. I had to re-set the IAC when the motor was fully up to temp. I think mine is set to be at about 20+ counts or so cold, which usually ends up about 10-18 or so at temp. It does vary with the air temp, it seems.

 

ok mine is idling perfect when warm, but has no iac counts how do i adjust to get iac to 5 - 10 counts without screwing other stuff up, tps min air?

Thanks

 

Once your motors completely warm turn it off. With your key in the on position backprobe your tps sensor (I think the two wires you want are the black and blue). Set your voltage for .57 After you do that, disconnect your battery for a minute or two to reset everything. Start it up and take a look at your counts. If the condition persists you'll have to close the butterflys a little more then redo the above procudure until it responds the way you want. Your getting too much air at the moment. Its a bit tricky and can be a balancing act but you should get it in a few more attempts. Your on the right track. Hope this helps. Brandon