Hi all.

I've got this high idle problem with my 245. I have checked the archives and played with the reults to no avail.

The car starts normally then the idle gradually rises till it is around 12-1500 rpm.

So far I have replaced the coolant sensor for the LH-jet and the constant idle valve. I'v also looked for vacume leaks and screwed the idle adjust all the way down. I removed the throttle body and cleaned it out, made sure it was closing fully. checked to see if the throttle switch was "clicking". I also looked at the cable and it was fine.

I can close the hose to the constant idle valve and the idle drops down to around 300 (with the idle adjustmend screwed all the way in).

The harness appears to be fine. When the coolant sensor is unplugged, the idle races to around 2k+.

Any suggestions would be helpful.

Thanks in advance.

Alan

I have been experiencing the same on a 240 of 1985 vintage. I have had the air by-pass motor replaced (at considerble cost!), the throttle body and valve replaced, and just about everything else in the fuel injection system that may impact idle speed. I am about to get the computer replaced / tested by a local Volvo shop. The individual there indicated that the control computer in these models were to be replaced by Volvo due to a "bug" in the computer in 1985/6 and that some of them exhibited this symptom. The problem with mine is that once in while it works OK.

Right now I am at wits end to try to get this thing repaired (and down $$$). So, I am hoping this last resort will correct the problem. One other bb response to my search for high idle indicated that the CIS temperature sensor may be at fault; when the sendor is unplugged the idle races to 2k+. This I will try tonight.

Regards,

Gordon Antonello

Alan,According to my Haynes 240 series '76-'93 chapter 1-17,on step 4,you should ground the blue/white test lead right by the battery.This will close the air control valve thereby not allowing the valve to interfere with the base setting.Then turn the idle bypass screw to your correct rpm level.Remove the jumper wire from the test terminal and observe that the rpm's increase slightly.If the engine speed doesn't change,it could be the air control valve itself or it's circuit. Hope this helps.Jim S.

Maybe a stuck or defective idle valve?

Try banging it with a hammer to see if you can "jar" it free. But they do wear out after a while.

Don Foster (near Cape Cod, MA)