[Doktor]

Truck started up fine last night as always.

Driving down the road a few miles from home, start running on what feels like 6 cylinders. Decide to turn around and truck starts running worse, maybe 4 cylinders. Finally quits 100 yards later. Won't re-start.

Tach needle moves up when cranking.
Fuel filter bowl is almost dry <-- Problem
I'm thinking lift pump or the lines feeding it but, are there any fuel pumps upstream that supply the lift pump? I don't think there are crawling around under the truck.

Won't pull fuel from either tank.

I'll dive in and change the lift pump, did it last in 08. Not that bad a job but, I'd like to hit this first time without just throwing parts at it.

It's not my daily driver but, my Dogs are crushed they've lost their truck over the weekend.

Thanks.

 

[dieselsmokerdoug]

sounds like the pump, or could be a crack in the fuel line between the pump and the valve that switches tanks .

 

[Doktor]

sounds like the pump, or could be a crack in the fuel line between the pump and the valve that switches tanks .

i poked around under the truck yesterday. Everything in the back from the tanks are dry. I'll order a pump and new lines. Hopefully that straightens it out.
Thanks.

 

[Doktor]

OK, so I changed the lift pump and all those short hoses around it and still no start and no fuel getting to the filter bowl.

Question, can the tank selector stick closed. I pulled the two flex lines where the metal lines off the frame connect to the other metal lines on the engine. I expected a gush of fuel and just got a dribble.

These trucks don't have any in tank pump, correct? With no in tank pump, no fuses or relays to deal with, correct?

Anyone have the p/n of those two lines? I guess I just start seeing where fuel will pull from.

 

[madpogue]

Correct, no in-tank pumps. You could disconnect the supply line from the selector valve and dip it into a jerry-can of diesel, see if that gets any fuel going into the bowl. If it does, then yeah, there's an issue further back, with the FSV or either/both tank pickups.

 

[Kimber1911]

OK, so I changed the lift pump and all those short hoses around it and still no start and no fuel getting to the filter bowl.

Question, can the tank selector stick closed. I pulled the two flex lines where the metal lines off the frame connect to the other metal lines on the engine. I expected a gush of fuel and just got a dribble.

These trucks don't have any in tank pump, correct? With no in tank pump, no fuses or relays to deal with, correct?

Anyone have the p/n of those two lines? I guess I just start seeing where fuel will pull from.

I've never looked closely at the selector valve, but I suspect it could be stuck half way to where the fuel pump was sucking air from the fuel return line.

You may also have a clogged line or a clogged selector valve. Remove the tank filler caps and blow air from the fuel lines in the front back towards the tank.

The only fuses in the system I can think of would be the fuel gauge itself and the selector valve. You might check the selector valve to make certain it gets voltage.

 

[Doktor]

I've never looked closely at the selector valve, but I suspect it could be stuck half way to where the fuel pump was sucking air from the fuel return line.

You may also have a clogged line or a clogged selector valve. Remove the tank filler caps and blow air from the fuel lines in the front back towards the tank.

The only fuses in the system I can think of would be the fuel gauge itself and the selector valve. You might check the selector valve to make certain it gets voltage.

Thanks guys for the info. Did some more investigation this am and filled filter housing with fuel, disconnected flex line from the front metal to the rear metal lines, rigged a pickup into a fuel can. Truck fired right up and idled for over 20 minutes. Chnecked filter housing and it was still full so I'm pulling from the make shift tank. Started disconnecting lines and blowing air thru them, all clear. It almost has to be the selector valve. Hard to believe both fuel pickups in two tanks would fail at the same time. Had wife move the switch while under the truck and it appears to move but, sounds really crappy moving, more of a groan than click.

I'm just going to replace it since it's already out and not very expensive.

Thanks for the info.

 

[bugman]

If I remember right the tank selector valve for our trucks is around $300. It isn't just a valve but a small motor that moves the valve back and forth.


How much fuel is in both tanks. The plastic foot on the fuel pickups have a habit of cracking and if you have less than 1/4 of a tank it will just suck air.

 

[Doktor]

If I remember right the tank selector valve for our trucks is around $300. It isn't just a valve but a small motor that moves the valve back and forth.


How much fuel is in both tanks. The plastic foot on the fuel pickups have a habit of cracking and if you have less than 1/4 of a tank it will just suck air.

Yeah. looks like about $300 for one. Neither tanks will pull fuel, front tank is about 1/2, rear is about 1/4.

 

[bugman]

Try putting 5 gallons of fuel in one of the tanks and see what it does.

Usually if the valve fails it will fail with it on one tank or the other and not where it will not draw from either.

 

[Doktor]

Anyone have the p/n for the supply line from the selector valve to the flex coupler up near the engine. It mikght be called the vapor/supply line. I can't find it anytwhere. If I could get that 90 degree fitting, I'll make one.

I have a long wheelbase, 161/ 168 inches.