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Discussion Starter #1
Well... my car diesels and im not happy about it. If it were a manual it wouldnt be as big of a deal because i would just put it in 4th and dump the clutch... then it would stop. Well since i have an auto, it just keeps trying to run. I dont know why its even doing this... isnt it usually a result of timing? My timing is perfect. Ive tried to retard, and advance it with the same results. What else could cause this????
 

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It's not always timing, although that can cause dieseling. If you get a little buildup in the cylinders, it can get hot enough when running that when you shut it off, it still ignites the mixture. You may also have some carbon buildup on a plug that can cause this. I'd try pulling the plugs and see how clean they are. Cleaning them up may help. It may also help to go to a range hotter plug. If not, it may require getting the heads out on your bench and taking a wire wheel to the combustion chambers! :p
 

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Timing has nothing to do with dieseling... When the ignition is off, the ignition becomes inoperable.

What causes dieseling is air and fuel are still going into the motor and enough heat inside the combustion chambers to partially ignite the mixture.

An anti-diesel solenoid would do the trick!

When energized, would hold the throttle open enough to allow the motor to idle, when the power is stopped (key off) the solenoid would retract, completely closing the throttle blades.
 

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Throttle blades are open too far at idle or, as Art mentioned, anti-dieseling solenoid is missing or defective.

What is current curb idle speed and vacuum readings?
 

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Until you get the source of the problem corrected here is a simple work-around: LEAVE THE SHIFTER IN DRIVE AND TURN OFF THE IGNITION SWITCH, THEN PUSH THE SHIFTER INTO PARK and THEN TURN THE IGNITION SWITCH THE REST OF THE WAY OFF TO REMOVE THE KEY. John
 

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Discussion Starter #6
Not sure what the vaccume readings are, but my idle is set at about 1000 RPMs in park, because the idle drops to about 800 when i put it in drive. I have a pretty big cam in the motor, so thats why the idle is set up.
 

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Just some guy
67 coupe, 69 Sportsroof, 86 hatchback
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Dieseling can be caused by many things or a combination of things. Adding a throttle solenoid is a good idea, that's exactly why Ford installed them on many 70's cars.
You might try "blowing it out". Cost-$0, takes maybe 5 minutes. So if it doesn't help, you've wasted nothing. Here's my method and some other VMFer's ideas too.
Blowing out Carbon
What have you got to lose?
 
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