Fuel Pressure Issue.

[imazdaman]

1989 LN9000 with Cat 3306 eng. It will not stay primed. I believe it to be pressure regulator cause the more I pump the primer, the more I can here it just flowing back in the fuel tank. Problem is, I'm not sure where the pressure reg is and I do't have a diagram. I figured it was at the end of the pump close to return line. But when I removed it, it was just a plug. Any idea's.

 

[Truck Shop]

The primer pumps have a check valve built in, the check will roll over causing it not seat.

 

[imazdaman]

Thank you for reply. On that note. I was thinking about that. But here's the problem. I can hear the fuel dripping back in the tank. If the primer itself was not holding with the check valve then I should not hear anything cause it would be in the fluid. But please if I am incorrect let me know. I think maybe the pressure regulator if it has one. It should.

 

[imazdaman]

Ok. So I took the fuel cutoff solenoid and bench tested it. Works. But key on, there is no power to the one wire. The other wire does go to ground. I'm thinking there should be a relay to control the voltage to the fuel solenoid. Tested them and the fuse for it. Good. Anyone have wire schematic of where the power to the fuel cut solenoid comes from. Please and thank you.

 

[Nige]

Anyone have wire schematic of where the power to the fuel cut solenoid comes from.

If you posted an engine Serial Number an electrical schematic for the engine should be easy enough to track down.

EDIT: Scratch that. There is notihng for a 3306 truck engine of any flavour. You'll have to rely on someone like @Truck Shop

 

[Coaldust]

New Feller,

Hello, welcome to the HEF. Helluva engine, that thirty-tree-oh’-six.

Truck Shop is correct. It needs a primer pump. There is nothing wrong with the solenoid.

 

[imazdaman]

The engine number is 63Z11879. Just need to know where the cutoff solenoid gets it power from.. Thank you.

 

[imazdaman]

New Feller,

Hello, welcome to the HEF. Helluva engine, that thirty-tree-oh’-six.

Truck Shop is correct. It needs a primer pump. There is nothing wrong with the solenoid.

I have since replaced thee pump due to the fuel leaking out the top. The old pump pumped just fine. I removed the fuelcut solenoid and bench tested it. It seems to work strong. But I do not have power going to it.

 

[cfherrman]

Old truck like that just run a new wire to a switched source in the cab

 

[imazdaman]

Old truck like that just run a new wire to a switched source in the cab

That is a great idea and makes since. Was thinking that also. With a descent relay or higher AMP kill switch.
Thank you.