bhamacher

I just replaced my Fuel pump in the Front Tank. When I switch it in the cab the Fuel Gauge works and I can hear the new pump running. But when I take it out on the road it Bucks and sputters like it is getting no fuel.

It runs fine when it is on the rear tank. Does anyone have any thoughts as to why this would be?

Also does anyone have any thoughts on why the truck would have no top end power? I was thinking that it may be the Cat's clogging up?

Thanks

Brian

Good old Bill

Am reading two concerns, no top end power and the starvation of fuel on front tank? Just because the gauge and pump run on front tank does not mean the valve has switch tanks completely. Verify the fuel valve is functioning.

bhamacher

Bill,

Thank You for the reply. I drove the truck into work today and the front tank is full of fuel. When I pulled into the yard I noticed the front tank was leaking. I am not 100% sure but I was thinking maybe the valve on the rail had failed and was not fully swapping the tanks.

Because if I am running off the back tank It should not be returning fuel to the front tank correct? Next Question I have is are the in tank pumps supposed to run or do the just prime at key on?

I appreciate your help.

Brian

klricks

If the switching valve is not working then it is possible for fuel to be returned from the FI to the wrong tank and overflowing your tank.

When the ignition switched is turned from off to run, the selected tank pump and the high pressure fuel pump on the frame rail will run for 3 to 5 seconds and then shut off if the engine does not start.

If there is a problem with a tank pump then the high pressure pump will struggle to get fuel and whine or make more noise than usual. The engine will starve for fuel especially at + 50 MPH...Bucking and stalling out.

If you have the non electric switching valve then both in tank pumps must be operational in order for the valve to work properly.
I could never hear the in tank pumps running but even if you can it does not mean everything is OK. To test you need to disconnect the fuel lines from the switching valve an run each tank into a container to check the flow rate.

The switching valve can be dissembled and cleaned up and you may be able to get it working for awhile. I ended up replacing it with a motor driven electric valve.

I have posted extensive information in other threads here about the duel tank system troubleshooting and fixing etc. Search duel tanks or on my username klricks.

Good old Bill

Nice job klricks, hopefully that clears up some questions for the members.

To answer his last question, yes, the pumps run for 3-5 seconds then turn off, the pump selected will turn back on and run continuously after the engine has oil pressure. Thats all in the computor strategy.