Engine idle speed

[chris g 0]

My 2.0 16v idles a bit funny some times. About 50% of the time it sits at just over 1000 rpm but the other 50% it sits at about 900 rpm. It also seems to be going up and down very slightly (50- 100 rpm) on idle.

 

What could be causing this?

 

Chris

[Baz2004 0]

Your ISV valve might need a clean out, also might be worth replacing the temp sensor for the ISV. Check your air filter & intake also for any blocks/build-ups. When was the timing last done on your car?

[Supercharged 2]

Also look for a VAC leak - check pipes and listen for hissing noises...

[chris g 0]

I know the exhaust manifold ic cracked, could this have anything to do with it? Where is the ISV, and what can I clean it with? carb cleaner or something? Timing will have been done today as I'm having all the belts changed. I'll see how it is when I pick it up.

[Baz2004 0]

 

 

Is to the right of the inlet manifold below the distributor. I soaked mine in petrol for a while seemed to clean it out.

[chris g 0]

Where abouts is the temp sender?

[Baz2004 0]

Im not sure where exactly where it is on the 2.0 16V but if you look on the right side of the head you will see all the switches/sensors.

 

Its No 2 in this photo of a 1.8 16V (behind the black wire) Im nearly sure the late 16Vs were a bit different tho. Its a single pin sender with a red and green wire, you can see the black plug broken off here in this pic. Be sure and check before replacing any of these senders cus I know the ECU is different on the late 94 16Vs.

 

 

[scarlett 0]

thanks guys - mine does this too, wasnt too sure if it was a big issue.

[Baz2004 0]

A cracked exhaust manifold could also contribute to this it might be worth replacing if all else fails.