Hi all,

I've got a 90 240 wagon w/230K miles. Throttle body is clean, cap and plugs good. It runs like a champ at 10mph and greater.

It idles OK, but not great; the RPMs are too low and it tends to die. I can gain more RPM by adjusting the butterfly valve to create a larger opening at idle, but then it tends to hesitate coming from a dead stop, and even occasionally has a small backfire.

I tested the idle control motor, and it reacts to 12v, snapping open and shut. However, if I connect the idle control motor but keep it where I can see it, and then turn the ignition switch on, it snaps shut. I hear the microswitch click when I open the throttle body, but the idle control motor doesn't react.

Is this a valid test, or would it have to be running to be valid? If it is valid, does the fact that, with the throttle closed, the idle control motor is also closed a sign that the microswitch is bad?

Any ideas?

 

You should be able to OHM the switch.
The switch clicks as soon as moved correct?
Also to test with the car running pinch the hose closed that leads to the intake hose and see if the car stalls. If not the idle motor isn't working.

You shouldn't adjust the throttle plate to make it idle.