Correct Idle Setting??
Thread Starter
Intermediate
Joined: Oct 2005
Posts: 38
Likes: 0
Correct Idle Setting??
91 Coupe, idles at 1200rpm I assume that 900 is ideal. What is the easiest way to adjust. I just recently purchased, and it was this high when I bought it. Appreciate any suggestions
Le Mans Master
Joined: Feb 2000
Posts: 9,715
Likes: 27
From: Kempner Texas
Idle speed is burned into the PROM, so it's not manually adjustable like a carb is.
The IAC, Idle Air Control, is a little stepper motor screwed into the throttle body. It has a pintel - a little tip - which is moved outward and inward to allow more or less air into the engine; thus maintaining the idle RPM that is burned into the PROM.
There's a tiny torx head screw on the driver's side of the throttle body just above where the cables attach to the TB. It's used to adjust the minimum airflow setting, BUT isn't designed to control the engine's idle speed.
The Tech Tips section on this Forum should have the step by step procedure for checking/adjusting the minimum airflow setting. If after checking that setting as being correct and the engine still idles too high, you'll need to look elsewhere for the cause. Most likely it'll be a vacuum leak, vacuum hose broken or disconnected, etc.
Jake
The IAC, Idle Air Control, is a little stepper motor screwed into the throttle body. It has a pintel - a little tip - which is moved outward and inward to allow more or less air into the engine; thus maintaining the idle RPM that is burned into the PROM.
There's a tiny torx head screw on the driver's side of the throttle body just above where the cables attach to the TB. It's used to adjust the minimum airflow setting, BUT isn't designed to control the engine's idle speed.
The Tech Tips section on this Forum should have the step by step procedure for checking/adjusting the minimum airflow setting. If after checking that setting as being correct and the engine still idles too high, you'll need to look elsewhere for the cause. Most likely it'll be a vacuum leak, vacuum hose broken or disconnected, etc.
Jake
