Idle control valve improperly installed?

[PHUTNGUYEN92]

Ingo,

Thanks for your thorough explaination! I clean and tested the ICV & it does work, vibrate with key turn to on but w engine off. I think the Idle switch has electrical issue because it failed the electrical continuity test I performed on it.

Does the idle switch also affect cold start? The car normally will die if I don't give it a little gas during cold start. The rpm initially starts @ around 1300 than sudden drops really low to about 200-300 rpm then dies. OnceI get it to start the idle will eventually drop to a steady 650, but does not hunt around. Any other insights?

[ischmitz]

Absolutely will affect cold start. With the DME controlled engine you’re not supposed to touch the accelerator and only turn the key. Everything else is done by the DME. If it doesn’t see the idle switch it will struggle to keep rpm stable.

Does the switch not measure continuity when it’s knob is pressed? If not that’s your problem.

Cheers
Ingo

[PHUTNGUYEN92]

Ingo,

This is how I tested for continuity.

To test idle switch electrically:
• Engine should be stopped. Remove harness connector from switch.
• Connect ohmmeter leads to switch terminals (42 and 44).
• Open throttle approximately 1 mm.
• There should be continuity with throttle fully closed and no continuity in all other positions.

Is this the test you are referring to?

[ischmitz]

Yes, that’s the test. Check that you hear/feel the click in the engine bay when the throttle is all the way closed. Maybe it’s a mechanical adjustment. If not replace the switch.

[PHUTNGUYEN92]

I'll test again after work and listen/feel for the click.

I also perform this test. The engine speed did not increase at all.

— To test idle switch harness and connector:
• Start engine and allow to idle.
• Disconnect idle switch harness connector.
• Engine speed must increase approximately 500 rpm.
• If engine speed does not increase check wiring to ECM.
• If no problems are found replace ECM.

Thanks for your help!

[PHUTNGUYEN92]

Originally Posted by ischmitz

Yes, that’s the test. Check that you hear/feel the click in the engine bay when the throttle is all the way closed. Maybe it’s a mechanical adjustment. If not replace the switch.

Ingo,

Thanks for the suggestion! It turned out that the idle microswitch wasn't being activated by the steel arm. I made adjustment accordingly. Now the cold start issue is gone and it's idling around 800 RPM, still little bit low. I'm thinking that the PO adjusted the idle low to compensate for the non working idle switch. Later tonight I'll try adjust idle to 880.

Thanks for your help!