Run on DIeseling RESOLVED

[GerryL]

I have a TR4 motor with a TR3 head with TR4 valve cover. The valve cover tube is connected to a conventional non triumph PCV valve. I disconned the PCV valve and blocked the manifold vacuumm connection. This solved my engine from running after ignition was turned off.

 

[Billm]

High idle speed will contribute to dieseling- did disconnecting the PCV valve lower your idle speed? If you had left it hooked up and lowered your idle speed that could have also done the trick.
BillM

 

[GerryL]

I had lowered the idle speed, tried advancing and retarding timing, and tuned carbs with colortune but had not been able to prevent the car from running with the ignition turned off. A friend had told me he had experienced the same situation with his Triumph. I was skeptical, but thought I would give it a try since everything else had failed.

 

[GerryL]

I foregot to mention that I had even used seafoam to remove any carbon, but this also did not change anything.

 

[vivdownunder]

Sometimes the cause is a hot spot in a combustion chamber. Dieseling brings stresses suspected of starting crankshaft cracks, plus other risks, so it's bad news.

Where dieseling can't be stopped with tuning tweaks, try leaving the car idle for 30 seconds before switching off. At the point of turning the key, floor the accelerator pedal. The engine gets a gulp of cool air that usually quenches the hot spot.

 

[TonyPanchot]

Are you using Hi Octane Fuel ?

 

[GerryL]

I have used mid grade.

 

[GerryL]

I have been running slightly hot and have advanced the timing which eliminated the overheating and the diseling problem.