How to test ICV? (Hard Starting)

[funcrew]

Trying to diagnose an intermittent hard-start issue on my M20B25. The ICV is squeaky clean, oiled, and moves effortlessly from open to closed and back again. Does not seem to have any kind of spring return though - stays wherever I put it. What function test can I perform on the ICV to rule this part out as a cause for the hard start?

Car runs great once started. Per several other threads on hard starting, I have already:

• smoke tested for vacuum leaks
• replaced injectors with rebuilt/flow tested
• new O2 sensor

If the ICV is good, I guess the fuel system tests are next. Any other ideas?

[jlevie]

Does the ICV vibrate when you switch on the ignition? If it does and the vane moves freely, it is working. As an FYI, the ICV has two opposing coils. By varying the current in each of the coils the DME can force the vane to take any position from fully closed to fully open.

Fuel system tests would be the next item on the agenda. Other causes of hard cold starts include aged ignition wires, distributor cap/rotor, bad plugs, a bad AFM, or a bad ECT sensor. If the valves are out of adjustment they can also cause starting/idling problems.

[funcrew]

Does the ICV vibrate when you switch on the ignition? If it does and the vane moves freely, it is working. As an FYI, the ICV has two opposing coils. By varying the current in each of the coils the DME can force the vane to take any position from fully closed to fully open.

Fuel system tests would be the next item on the agenda. Other causes of hard cold starts include aged ignition wires, distributor cap/rotor, bad plugs, a bad AFM, or a bad ECT sensor. If the valves are out of adjustment they can also cause starting/idling problems.

Thanks - All the tune-up stuff and the ECT are fresh, so will try fuel system next.