Dieseling...
 

Our 68 mustang is dieseling when its shut off. Other than that everything is running fine. What would be causing this?

Skyler

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1989 Saleen Mustang #406
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TFS Heads, Edelbrock Intake, E-303, 3.73's, 23degrees of timing and 87octane, and all the little stuff.
2.44 60' -
13.5@105.41mph 225Radials
2.0 60' -
13.2@105.81mph ET Streets(100+Degrees)

Run a higher octane fuel. Should cure the problem.

Ron

If that doesn't work check the plugs and make sure you are not leaking fuel after shutdown.

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69 351W Sportsroof deluxe

What should I check the plugs for?

sky

------------------
1989 Saleen Mustang #406
-----------------------
TFS Heads, Edelbrock Intake, E-303, 3.73's, 23degrees of timing and 87octane, and all the little stuff.
2.44 60' -
13.5@105.41mph 225Radials
2.0 60' -
13.2@105.81mph ET Streets(100+Degrees)

Bad timing and vacum leaks will do this.

Carbon deposites in the combustion chambers will remain red hot and do this. High idle leads to this also. Retarded timing is another culprit.

Rev

Skyman,
You have to keep in mind what dieseling is, the engine wants to keep running after the ignition is shut off. It will need two things fuel and ignition, first the ignition can be caused by parts in the combustion chamber (valves, plugs & carbon deposits) getting so hot that they ignite the fuel. Second, comes the fuel from either low octane fuel, leaking carb, high idle or timing being advanced.

Did this always do this or did it just start?

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69 351W Sportsroof deluxe

Clark- This just started, since a new FMS motor was put in to the car. The 600cfm edelbrock carb is fairly new too. It has 10degrees of timing and 87 octane. I thought it had to do with timing being retarded too much.. am I wrong?

Skyler

------------------
1989 Saleen Mustang #406
-----------------------
TFS Heads, Edelbrock Intake, E-303, 3.73's, 23degrees of timing and 87octane, and all the little stuff.
2.44 60' -
13.5@105.41mph 225Radials
2.0 60' -
13.2@105.81mph ET Streets(100+Degrees)

Retarded timing wouold promote deisling. Advanced timing would lessen it. This is true.

Rev

Skyman, Rev's right, it looks like more than the timing is retarded http://www.mustangworks.com/interact...rd/biggrin.gif

Clark, I wasn't trying to criticize. I often have to draw a diagram to get these things straight. Alhzeimer's?

Rev