Chevy Corvette Forum banner

Tuning at Idle

6K views 4 replies 4 participants last post by  SS39 
#1 ·
A tip about tuning at idle.

DO NOT TRUST YOUR WIDE BAND.

Wide band readings at idle are typically thrown off and can read more rich or lean depending on your cam.

The correct way to set the idle is to disconnect the IAC, Tape off or otherwise block the holes in the throttle body that go to the IAC.

Set the idle you want using the screw on the throttle body blades to get it close.

Make it leaner and leaner until you get an RPM drop. Then make it slightly richer.

Remove the tape over the holes on the throttle body and reconnect the IAC

That should get you where you need to be.

Do not look at your Wide Band as a guide.
 
#2 ·
Just to add and since its happening to me. DO NOT live by these WB02's you put in the car. When street turning go by your BLM's more that that wide band. Look at those just a a general guide.
They are not as accurate as one used on a dyno.

Good advice up above
 
#3 ·
Unless, of course, you don't have a stock ECU....:D Then there aren't any BLMs.
 
#4 ·
90 Vette Idle problem

Before you inform me that I don’t know my whatever from a C4/C5, catch the clam shell hood. The car in fact turns out to be a C4/C5. When the engine was rebuilt the heads were shaved, modified for larger valves, and a roller cam installed. Any EM controls are no longer functioning or there including the catalytic converter. Now that I've put 2,000 miles on it the idle has gone from 1,000 rpm to 1,300 rpm. How should I lower it?
 
This is an older thread, you may not receive a response, and could be reviving an old thread. Please consider creating a new thread.
Top