budtaylor

After having some difficulty with my idle dropping out and surging to 1500 rpm we took off the isv and cleaned which seemed to make the problem a bit worse if anything.

My local mechanic suggested that I should just buy one because they always go bad but I am suspect of throwing parts at a car. I did replace the O2 sensor already with no results.

After looking at the thing myself (which is a dangerous proposition but I am a bit desperate) I can see that the throttle is not closing against the microswitch. When I force the throttle closed against the microswitch it idles perfectly.

Q: Could the springs on the 20 odd year old throttle be shot and need to be replaced and does the spring actually cause the throttle to "close" against the microswitch ? Even when I close the gap with my hand (throttle to microswitch) it idles normally then once I release then it returns to the high idle (1100 RPM)...there does seem to be a very tiny bit of play where it is supposed to close on its own. If there is a spring which does what I am thinking (ie pulling in the closed direction) can you replace it ? I really have to wonder after reading the forum if a bunch of people might be having the same issue...The car idles better than it ever has (almost dead even insead of 600 to 800) when I force the microswitch closed. Tried some WD 40 but that would have just been to easy...

scped

there is a thread titled "C2 Stalling in traffic" you may want to check. Here is the response I added when faced with your exact issue:

Here is an additional cause of the erratic idle / stalling issue I had.

I removed the engine to replace the insulation, detail, paint the fan, ...) over the summer and all ran great afterwards. When the weather (here in NH) started to get colder, I had occasional fits of stalling / rough idling.

It turned out to be the throttle cable length. As the outside temperature dropped, the metal cable experienced "shrinkage" which in turn caused the microswitch to no longer make contact. A quick adjustment of the coupling under the car solved my car's problem.

Cheers,
Scped

Makmov

That is a common problem or someone R&Red the motor and didn't get the throttle cable out the correct way and screwed it up. The cable is a sensitve thing and need to be just right for proper opperation, and they often end up getting to tight for one reason or another.

budtaylor

After douching the spring and throttle mechanism and taking a drive it would seem to be surging now to only 1K to 1100 RPM ???

ThomasC2

I agree, ckeck the play in the throttle cable and start at the pedal.

Thomas

hamah

on page 6 of Babalouie's thread "Aussie 964C2 Maintenance Diary (pic heavy!)" he discusses taking the ISV off the car and REALLY cleaning it. Might be worth a shot.

budtaylor

The above advice was great took it to the dealership and a minor adjustment to the throttle cable fixed the problem...dealer charged me $60. and I was in shock !

ThomasC2

Nice with a simple fix!

Thomas

August West

$60 sounds like 1/2 hour labor charge, probably the minimum they'd have to charge, and if they were to check/clear fault codes from the computer as well, I'd say $60 is cheap.

Consider yourself lucky!