High idle issues;
I started at the point with the crank at 0-degrees TDC and ignition distributor @ cylinder one.

I can retard the timing to bring the idle down but it runs/sounds crappy. Put it back to TDC with ignition distributor mark on cylinder one.

I did the smoke test but I ran out of smoke. I had enough to check for obvious signs or huge leaks. I will do the smoke again to detail any small leaks should there be any. My main concern was to find any large leaks with the larger hoses that connect at the injector holders, ICV boots, air intake boot, donuts or anything under the intake.

Can someone explain how the ICV works or how it functions? How to diagnose further than I have done already?


At first, when I checked the ICV, there was no voltage. The overload protection relay was fine and when testing out the ICU (or ICM), voltage went in but none came out. I changed the ICU. At that point I had battery voltage at the ICV using a test light. After the warm up, the test light would hardly glow which indicated lower a voltage. All the while I still had high idle, even after disconnecting the power to ICV.

Today, I removed the ICV and cleaned it up. Powered with external 12volts to check operation and it appears fine. Put the ICV back and started the motor. I decided to check voltage with a volt meter this time. It's odd, while I checked for voltage on the back side of the ICV harness, at the ICV pins, I couldn't get a steady reading. The voltage changed all over the place. So I figured, let me check with the wire harness connector removed [ I removed just the top barrel connector which is (+) and kept the bottom barrel connector (-) on the ICV ] and I got battery voltage which I expected. Put the top barrel connector back on and got whacky voltages again. After warming up I did the same procedure, except this time, with both barrel connectors on the ICV and got a voltage reading of .99 V. When I removed the top barrel connector as before, I got battery voltage again. All the while the motor still idling at 1500.

~I removed the the throttle body linkage to see if it might be stuck open a little somewhere, nope-
~I cleaned the ICV and not sticking. Checked operation off vehicle and looks good-
~No change in idle with ICV harness connector on or off-
~No major vac leaks that I could find but I do have to smoke again-

I am thinking there may still be an issue at the ICU since it doesn't drop the voltage with the harness disconnected - unless I am doing something wrong with how I am taking my readings. There could still be a bad temp sensor feeding/not feeding the ICU, then not giving proper (3-5V) voltage to ICV, I will check that next. But still there was no change of idle with or without the voltage on the ICV.

Not sure which way to go on this but I am thinking of checking pressures at the WUR and rebuilding it if need be.

Any help would be fantastic!!

Thanks !!