base idle, TPS, IAC, Timing - what is the correct sequence?
Thread Starter
Melting Slicks
Joined: Jan 2001
Posts: 2,940
Likes: 5
From: Chesapeake VA
base idle, TPS, IAC, Timing - what is the correct sequence?
Hello all,
I am working on getting my idle smoothed out and set properly. I have an 86' auto. The car has 81K on it. So far I have replaced the plugs, wires, rotor & cap. I removed and cleaned the throttle body, and after that the idle increased to 800 in gear and 1200 in neutral at operating temp. I plan on replacing the IAC valve. I know I need to set the base idle and the TPS, but I think I should also check the engine timing. The throttle body also has the cover on the set screw, so it has never been touched. My questions are:
- What sequence should I do these things in
- Should I touch the set screw for the base idle since it has never been touched
Thanks!
I am working on getting my idle smoothed out and set properly. I have an 86' auto. The car has 81K on it. So far I have replaced the plugs, wires, rotor & cap. I removed and cleaned the throttle body, and after that the idle increased to 800 in gear and 1200 in neutral at operating temp. I plan on replacing the IAC valve. I know I need to set the base idle and the TPS, but I think I should also check the engine timing. The throttle body also has the cover on the set screw, so it has never been touched. My questions are:
- What sequence should I do these things in
- Should I touch the set screw for the base idle since it has never been touched
Thanks!
Drifting
Joined: Aug 2001
Posts: 1,550
Likes: 27
From: Minneapolis MN
Race Director
Joined: Sep 2000
Posts: 17,298
Likes: 33
From: The Top of Utah
base idle, TPS, IAC, Timing - what is the correct sequence?
2.) Base Idle.
3.) TPS.
4.) There really IS no IAC adjustment. Only an installation position proceedure. It will self adjust through normal operation. I think the "self adjustment" sequence is in the "Tech Tips" section, or 65Z01 has it on his web site. However, that will only expedite what will come "naturally" and not affect the other settings.
RACE ON!!!
Team Owner
Joined: Dec 2000
Posts: 90,675
Likes: 304
From: SE NY
Cruise-In II Veteran
CFI-EFI has the right sequence.
I would also clean the IAC bore and pintel with some TB cleaner before pulling the IAC motor.
Since you cleaned the TB it's likely that the IAC is dirty and now cannot shut down air flow enough at idle.
I would also clean the IAC bore and pintel with some TB cleaner before pulling the IAC motor.
Since you cleaned the TB it's likely that the IAC is dirty and now cannot shut down air flow enough at idle.
Le Mans Master
Joined: Dec 2000
Posts: 7,839
Likes: 22
From: San Diego, Ca
Try resetting the IAC first. Slightly depress the accelerator and start it. Let it run for 10 seconds; shut it off for 5 seconds, then restart. If the idle is normal, that's all it needed.
Thread Starter
Melting Slicks
Joined: Jan 2001
Posts: 2,940
Likes: 5
From: Chesapeake VA
Thanks guys!
I will acquire a timing light and replace the IAC and clean the housing. I tried to replace the IAC when I cleaned the throttle body, but it was quite insistant on staying put and I didn't feel like pressing the issue at the time.
Thanks again! I will report the results.
I will acquire a timing light and replace the IAC and clean the housing. I tried to replace the IAC when I cleaned the throttle body, but it was quite insistant on staying put and I didn't feel like pressing the issue at the time.
Thanks again! I will report the results.
