Throttle Position Solenoid
Postmaster
Joined: Mar 2011
Posts: 2,698
Likes: 7
From: Taxachusetts
You could do a search on the 'net or this forum.
Go here:
https://www.ford-trucks.com/forums/1...rb-tuning.html
Go here:
https://www.ford-trucks.com/forums/1...rb-tuning.html
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New User
Joined: Apr 2016
Posts: 22
Likes: 0
Thanks for the links, I read the Choke operation in the Sticky thread already and also the other link was good as well. My carb is running well, just a slight hesitation at 1/4 throttle from a stop. and when my AC is on the idle is too low. so I was wondering if that was the function of the Throttle Position Solenoid.
Hotshot
Joined: Apr 2009
Posts: 14,333
Likes: 247
From: Stanley, VA
That's actually an anti-diesel solenoid.
Back in the day, because of the somewhat prehistoric emission control systems, when you shut the ignition off the engine sometimes wanted to run-on (aka "dieseling"). The way Ford tried to avoid this was this solenoid.
With the ignition on, the solenoid is extended and holds the engine at the set idle speed. When you turn the ignition off, the solenoid de-energizes and retracts. This allows the throttle to close completely. Hopefully it would keep the engine from dieseling. Sometimes it worked, sometimes it didn't.
With modern fuel injection, there is no dieseling problem. You shut the engine off, you shut the fuel supply off. No way to diesel.
Back in the day, because of the somewhat prehistoric emission control systems, when you shut the ignition off the engine sometimes wanted to run-on (aka "dieseling"). The way Ford tried to avoid this was this solenoid.
With the ignition on, the solenoid is extended and holds the engine at the set idle speed. When you turn the ignition off, the solenoid de-energizes and retracts. This allows the throttle to close completely. Hopefully it would keep the engine from dieseling. Sometimes it worked, sometimes it didn't.
With modern fuel injection, there is no dieseling problem. You shut the engine off, you shut the fuel supply off. No way to diesel.
Postmaster
Joined: Mar 2011
Posts: 2,698
Likes: 7
From: Taxachusetts
From another forum - To adjust: first unplug it and back off the screw so it won't contact the throttle linkage. Then adjust the idle speed to 500 rpm with the throttle plate stop screw (just on the edge of a stall). After that, plug in the solenoid and adjust the curb idle to 800 rpm (or what's listed on the emissions sticker if it's still there). All of this is done on a warm engine.
This allows the solenoid to control the curb idle, and when the key is turned off the solenoid retracts and allows the throttle plate to close enough to prevent shut-down dieseling with a hot engine.
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