Won't shut off when hot

[Eric Ditwiler]

I have a 1984 6.9 and when it is hot, it won't shut off. It has a turbo cool-down thing that is supposed to keep the engine running until the EGT drops below a certain level so I first thought it was that but its electrical and the beast kept running even after I disconnected all the wires to the IP.

I recently started using what they call "an engineered hydrocarbon" and what I call "biodiesel" could it have dissolved some old-school rubber seal so that fuel is still getting through?

I have ball valves in the fuel line for an extra filter under the cab before the electric lift pump so I just starved it last time. Are there any adverse consequences to shutting it down this way?

 

[Thewespaul]

With the key on, if you connect the front prong on the injection pump do you hear a click?

 

[Eric Ditwiler]

With the key on, if you connect the front prong on the injection pump do you hear a click?

Yes, I do hear a click.

 

[Thewespaul]

Well even with it clicking it has to be an issue with the condition of the shutoff solenoid or how it was installed. Pull the top cover off and see if the body of the solenoid is cracked or split.

 

[Selahdoor]

Has the top cover been removed and replaced already?

Could have been reinstalled incorrectly, and holding the fuel shutoff open.

 

[Eric Ditwiler]

I have not touched the IP since timing it and this just started happening. The hotter the engine, the longer it takes to shut off. Are the valve surfaces metal or rubber?

 

[Thewespaul]

There is not a valve that shuts off the fuel, it’s a solenoid that extends and pushes the governor linkage forward, closing the metering valve.

 

[Macrobb]

Which means it could be the fuel shut off solenoid literally sticking in it's bore due to crud in there. Probably time to remove the IP lid and inspect it.

Alternately, try filling the fuel filter with ATF, let it run for about 30s till the ATF gets into the IP, shut it off, and wait all night, fire it up and run it hard!
That may help clean it.

 

[Eric Ditwiler]

I left the coil energized with the engine off and it stopped clicking when I removed the wire after about 3 minutes with an energized solenoid coil. The coil must be getting hot and binding on the shaft that is supposed to slide inside it. I ordered a new solenoid and will attempt to replace it on the first non-windy day after it arrives. Thanks to everyone for their help in figuring this out!