Question about choke solonoid on 75 6 cyl.

[Eric M.]

I just picked up a 1975 1/2 ton with a 250 inline 6 cyl, 1 barrel. There is a solonoid that pushed out the throttle when cold. When the engine warms up, the solonoid is suppose to release and drop the idle. Problem is, mine never shuts off. I can pull the wire off the back and it will drop the idle. I have no idea what controls this solonoid. I assume it would be a sensor screwed into the side of the block, but I'm not sure.

Anyone know??


Thanks in advance.

Eric M.

 

[4X4HIGH]

That is called an anti dieseling solenoid. When the key is in the on position the piston extends slightly opening the throttle, your idle is set with that extended and its purpose is to keep the engine from diesling when you shut the engine off. The way it works is when the ignition switch is turned off the solenoid relaxes and the throttle blade closes completely shutting off any fuel that might still be present so it won't continue to run or diesel if you will.

 

[Eric M.]

Ahhhhh, no wonder I can't get the damn thing to stop dieseling! Now it all makes sense. Thanks.


That's what I love about this place .... ask a question at 11:30 PM and by 1AM you got an answer!

Eric M.

 

[R72K5]

yeah its anti dieseling solenoid yep

also its supposed to kick idle up for a/c, etc that will drag the engine down a little

when the solenoid is used for anti dieseling then your normal idle speed is adjusted at it, and the normal idle screw is used to limit how far the throttle valves close in the base of the carb, have to prevent them from bottoming out though, need ot be left open a tiny hair at least, but way less open than the engine coudl run with



good luck