Adjusting idle

[stefan]

What is the procedure for adjusting idle speed? with my new t-body it idles really low, around 500 or so once warm. do i just adjust the air bypass screw on the t-body or is there other adjustments?

[kzbill]

if the timing is set correctly, I know I have only been able to set mine that way (air bypass) workd good for me. the throttle plate is preset to be just closed without damaging the bore. so it shouldn't need to be played with.

[stefan]

Ok, but which do you adjust first? The timing or the idle? Because in the book, under timing it says to set the idle first. And under idle it says to adjust the timing first.

[FB71]

set timing first. timing advance is not affected below 1000rpm.

get the engine up to operating temp, then either pull and plug the vac line (carbed car) or short the spark advance pin in the test connector (fi car). Set your timing. Now, make sure the engine is at operating temp for this get a tach connected to the coil negative (or inductive on #1 plugwire) don't trust the dash tach, they can be off by up to 500rpm. Being at operating temp ensures the Bypass Air Control valve is fully closed (BAC is a coolant operated oriface, used in conjunction with the Idle Speed Control valve). Now you can adjust the throttle plate idle screw

[WmWatt]

Agree with above except in carb'd engine do both, plug vaccum advance line (top one on distributor) AND ground spark advance wire (single wire white connector at driver's end of fire wall)