Drove my truck to the store today. When I got ready to leave it stalled (a first) but started right back up and then stalled again. I immediately checked the fuel gauge and I was in uncharted territory as the needle sat right at 1/4 of tank. I'm one of those that keeps the top half of the tank full so never been this low before.

Having read stories about broken fuel pickups not reaching the bottom of the tank I sent for more fuel. When my friend arrived we poured a couple of gallons in and the truck fired right up. Off to the gas station to put some more diesel in.

Pulling out of the gas station it stalled again. Now I am in a bit of a panic.

Remembering that I had recently pulled the 42 pin wiring harness I started inspecting all the connectors thinking maybe something was loose. Once again the truck fired right up and I drove it 8 miles into town with no issues but then it started bucking and acting like someone was turning the ignition key on and off rapidly. Slowed to a crawl and then it stalled.

Started it again and crawled along for a while before being able to accelerate. It definitely sounded fuel related and I decided to check the pre-pump filter I had installed. Diesel flowed all down my arms and soaked my jacket. This wasn't the problem.

Went back up under the hood with a flashlight and inspected every inch of the harness when I noticed something amiss. The drain valve for the fuel filter was partially open. Could it be that simple? Yes, it can! Once I had fully closed the valve my truck starting running like a champ again.

Apparently I had caught the wiring harness on the drain valve handle and pulled it partially open without realizing it.

Feeling very relieved right now as I was expecting big money issues.

 

Dang, I love easy fixes like that!

Having taken a Diesel bath today (installing a pre-pump filter), I empathize with the results of your diagnostics.

 

 

Reps.

Stewart

 

Prescott, AZ
I live in Paulden so not far away.

 

That fuel drain valve is also a common problem. Eventually it will wear out and start to leak. May need replacing. Not a big job. Just something to remember.

 

I can't think of any reason that the valve not being fully closed would do this. My guess is it was a harness/connection that you fiddled with and not the valve. It's remotely possible that the foot is bad and that there was still air trapped in the system, but an electrical issue is more likely.

I suggest going back over the harnesses/connections with the engine running to see if you can pinpoint where the issue is so it doesn't get worse. And to eliminate the fuel valve as a potential culprit you can move it back to where it was with the engine running to see that it won't make it stall. You'd have to open it enough to have an obvious fuel leak before it would cause the engine to stall, I'm not even sure it could flow enough to kill the engine with the valve wide open.

 

Thanks. I will be driving the truck this morning and once it is warm I'll try wiggling some of the connectors to see if anything happens.

A number of years ago I had a car start acting like this. Too much accelerator and it would die, driving at speeds it would start chugging and begin to slow down, stall but restart and idle okay, etc. That turned out to be a clogged fuel filter. These symptoms are nearly identical. Hence my suspicion that the fuel was not flowing properly through the system.

When I had first discovered the valve half open, I tried to turning it more open and it caused the truck to run worse, when I closed the valve it ran much better. Hopefully my drive today will verify one or the other.

 

My hats off to ya! Truck ran great all day and when I got home I decided just for grins to check each connector. Sure enough the black connector to the Glow Plug Control Module was just barely making contact. All I did was touch the wire and the truck began to misfire.
Turns out it wasn't seated completely because of a twisted seal.
I fixed that and then added some wire ties to make sure those connectors don't back out again.

I guess only those with the California emissions (read: Glow Plug Control Module) would ever run into this problem.

Thanks again for your insight and instructions.

 

Thanks for the reminder on ties to secure the GPCM plugs. Top of my truck PM schedule.

 

Glad you got it.

 

Reps revoked for previous reason being invalidated. (ok I can't really do that, but we'll pretend)

New reps given for correct fix being posted. (Again, we'll pretend) It all evens out in the end!

Stewart

 

I have always been under the impression the the GPCM is just fancy GPR that feeds power to the GP's individually. I had to replace mine as one bank was bad but it would start and run fine unless it was pretty cold, but even then it would just romp for a few seconds and clear up.

 

Ha,ha. I sincerely thought I had found the problem. Truck ran perfect until I started wiggling connectors.
Sorry for the extra work!

 

I feel like the middle man, I live in Chino Valley.