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How To Test Idle Shutoff Valve?

Go to solution Solved by FunkyLaneO,

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My 1976 won't stay lit under 2500 ro 3000 rpm.

It has 40,000 actual miles, was a Cali car which I desmogged.

Ran perfectly until I "fixed" it ;>)


Tii type exhaust manifold was the only change, other than desmogging.

I am hoping the idle valve went bad coincidentally.


While my idle shutoff valve does go click click when powered on,

I don't see any movement when looking into the 4 small holes at

the tip. So, I ignorantly assume I should see a plunger slide down

into the valve and open up those holes, yes?


If so, I think I've solved my problem (famous last words) for about 120 or 140 bucks.

Unless a kind soul has a used one for less?



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  • Solution

Did you save the original jet holder when you swapped in the solenoid? if so then you can use that in place of the solenoid to test it's operation. If the solenoid is bad it is only a $15 part and the last one I bought had a 60 jet in it for that price.


My test has always been that if it clicks then it works, I have never been able to see the actual plunger in the cutoff solenoid but it is usually installed when I am testing it.

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  • 1 year later...

My car suddenly would not idle, so I pulled the solenoid to inspect it.  I removed the jet and put power to the solenoid and the plunger did not move, unless I gave it a little push; then it would click open.  


I figured I had found my problem, but then realized that the plunger does not reach the fully extended state while in the jet.  It appears to work fine when slightly depressed, like when the jet is installed. 


I guess I will look elsewhere for my idling problem, but thought I would add this information to this solenoid test thread.


Power Off



Power On




Did you save the original jet holder when you swapped in the solenoid? if so then you can use that in place of the solenoid to test it's operation.





or buy a normal idle valve housing.. new or used, and put the idle jet into it.  



I have read many references to swapping in a 'normal' jet holder, but the size is different.  If anyone knows of a larger holder that eliminates the solenoid, I would be interested in seeing it.  I have been searching online, through Pierce Manifolds and others, but have not found such a thing.


Here is a photo comparing the sizes



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