Missing Idle Control Valve
 

I think the PO may have removed the idle control valve (I have no idea why). What are the symptoms if it's missing? Do I need it? How hard/expensive is it to put back? TIA.

Minh

a low rich idle at startup when the engine is cold. More noticeable during cool or cold weather. May have to give it some throttle to keep it running til it warms up a bit.

Thanks for the reply. So once the engine warms up, it's not needed anymore? Anyone know why someone would want to remove it in the firstplace?

The idle control valve called auxilary air valve on pre 85 and older cars. It lets extra air in on a cold start to mix with the longer injector gas squirt. Once the car warms up it is really not needed although on 85.5 and newer cars it does open and close a bit after it warms up just to regulate air but only at idle. On a 85 and older car the heat from the engine closes it when warmed up. But bacically, no its really not needed when warm, its closed then, and not that much when cold if you are talking florida or warm climates. I live in KY and I need it for the winter but in the summer when 80-90 degrees not a big problem at all. I would guess yours went bad and the PO didn't want to shell out the money for a new one as the are about $120-150 for 85.5 and newer and maybe $60-90 for 85 and older cars.

Could a missing idle control valve also be the cause of hard starting? Cranks for a while then starts (a few seconds). Thanks again everyone.

Minh

If you turn on the A/C and the idle speed drops a lot, you probably don't have the valve. There are lots of causes of hard starting.. I wouldn't think this would be one of them, but maybe.

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'86 951 Graphite Metallic/Tan