Thread: Idle stop solenoid help

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I have a 1972 454 with as idle stop solenoid. The carb is a factory rochester. I don't understand how this solenoid works. I do know that when the connection wire is attached, the idle increases about 300rpm. Is it only supposed to work when the AC is switched to on? Thanks for any help

yes that is what it for

These dashpots were in wide use in the '70's. We had just experienced the Arab Oil Embargo and the manufacturers were forced to drop compression ratios dramatically to cope with the cat-pi** gas that was available at the time. They also began to run the motors hotter to try to help with emissions and placate the "green" people. If there were any deposits in the chambers or burrs on the spark plug or even a head gasket that overhung a little, they could glow red from the heat of combustion. Then when you turned the key off, the throttle blades were still open at the idle position and the motor would pull in enough fuel/air mixture to diesel, with the hot spots in the chamber igniting the mix.

The fix was to install a dashpot that held the throttle blades open to the idle position when the key was on. With the key off, the dashpot relaxed and closed the throttle blades fully so that no mixture was introduced into the motor. No mixture to burn, no dieseling.

I had a 78 LTD which I put a toggle switch on the dapshot for a high idle when it was cold.

hey, I was 16. It worked.

Techinspector1 has the correct answer. It was never meant for bumping RPMs for the A/C although some of us rewired it that way, hehehe!

Actually, I seem to recall that on that 78 LTD it DID come on for the AC. Factory wired that way.

Originally Posted by DennyW

Yes, that is correct.

were was a noid for AC and a dash pot for the diesel i was stinking

Originally Posted by Twitch

Techinspector1 has the correct answer. It was never meant for bumping RPMs for the A/C although some of us rewired it that way, hehehe!

No Denny W is correct . Look in any shop manual and you will see .

Such the wealth of knowledge from my brotherly scholars of club hotrod.
The solenoid activates whenever i plug the wire to it. It must be wired wrong. I will connect it to the AC wiring. Thanks again guys

1972 monte carlo with factory air and 402. The wire going to the solenoid must be hot wired because I plug it to the solenoid with the air off and it raises the rpm about 300-500. It seems like it used to work when I first bought the car and since then, I have not done anything to change the wiring. When I used to start the car when it was cold, it used to idle very high( a warm up idle) and when the gas pedal was depressed after a short period of time, it would go to a normal idle. Now, during a cold start, it just idles a low rpm and I have to keep pumping the accellerator until it is warmed up. I will have to trace that wire back and find out what is going on. I may have a choke issue too. I have the old divorced choke style. Thanks again in advance for your info.