Can anyone tell me exactly where the aldl connector is that must be grounded as part of the procedure for setting the idle speed? how do you ground it? Previously I "adjusted the idle" by turning the throttle stop screw. It idles higher but the TPS voltage is at .9, should be around .55 or so. AND the throttle plate is opened too much causing a vacuum leak at idle. I am going to have to set it the right way to eliminate the vacuum leak and to get the TPS reading where it needs to be. I have done a search for this topic already and haven't found the info I need. Thanks!

[This message has been edited by speedlvr (edited February 28, 2001).]

 

underneith your dash under you steering wheel, its square, you might have to take off the plastic peice to see it, but it dont think so.

 

You can't adjust the idle. It's programmed into the computer and will idle close to that rpm no matter how much you change the air door adjustment, with the exception of going so far that the butterflies are held open too much-which will raise the idle. All the adjusting screw changes is the position of the IAC motor so the motor has enough air to idle at the programmed idle speed. At extremes, this will also show higher tps voltages, as you have discovered.

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'93 2wd truck
408 sb, vortecs, 454 TBI, Comp Cam, dual exhaust

 

So, how do you adjust the idle? I want to do that as well, it's so low, when i slow down and I put the clutch in, the light dim. Damn that sucks, than it climbs back (slowly of course), it's really annoying. The new cam I'm putting in, sure won't like that! PLease help.

Ethan

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'88 T/A
305 TBI with WC-T5
50,000 miles
Flowmaster 3" exhaust
14" K&N Open Element

 

Tonight I found the easiest way of all and you don't have to mess with the throttle stop screw which in turn, changes the TPS voltage. What I did was put a spacer between the end of idle stop screw and the throttle linkage. Made a big difference without causing a vacuum leak at idle resulting from an open throttle plate. Also, when you try to adjust the idle by just turning the screw, it increases the TPS voltage making the ECM think the engine is under a heavier load than it really is causing a lean condition at idle.