i have a 1997 ford f350 xlt w/ 7.5. Front pump doesnt stop running when idiling and rear tank is filling front tank as well. Cuts off and doesnt want to start for 5 to 10 mins. getting to be a real pain. any ideas fellas?

 

Sounds like your fuel selector valve is going bad... I think NAPA has the exact replacement for around $90.

 

The OP's truck does not have a fuel selector valve. Each fuel tank has it's own Fuel Delivery Module that contains a high pressure fuel pump, fuel level sender, check valve and a shuttle valve that blocks off flow depending on which tank is selected.

This problem is referred to as "fuel transfer" and it is a VERY common issue on this vintage truck. The OP needs to replace the front pump.

I am a little confused with the opening statement "Front pump doesnt stop running when idiling". The pump is not supposed to shut off when the truck is idling.

For reference:


Fuel Delivery Module (FDM)

The electric fuel delivery system used on the 4.9L, 5.0L, 5.8L and 7.5L Electronic Fuel Injection (EFI) engines consists of a fuel delivery module (FDM) assembly. The FDM unit includes a high pressure fuel pump, venturi jet pump, supply check valve, and a shuttle selector valve located internally to an in-tank reservoir assembly mounted from the fuel tank sender flange.

The following provides a brief description and function of each of the FDM internal components.

High Pressure Fuel Pump: The high pressure fuel pump is located inside the flange-mounted, reservoir assembly internal to the fuel tank.

Shuttle Selector Valve: The shuttle selector valve opens the return line to the tank and the return flow is directed to the appropriate tank on vehicles equipped with dual tanks.

Supply Check Valve: The supply check valve, which is normally closed, opens when the outlet pressure from the energized pump exceeds the opposing check valve spring force. When the pump is de-energized (i.e., engine is shut off), the supply check valve closes to maintain pump prime and fuel supply line pressure.

Venturi Jet Pump: A portion of the high pressure flow from the pump is diverted to operate the venturi jet pump. The venturi pump draws fuel from the tank into the ITR reservoir to augment the engine return flow. This process ensures an adequate fuel supply to the pump during extreme vehicle maneuvers and steep vehicle attitudes with low-tank fill levels.

The inlet of the venturi pump has a nylon filter on it to prevent dirt and other particulate matter from entering the system. Water in the fuel tank can pass through the filter without restriction.

 

i meant to say the pump hums really loud and you can deff hear it over the dual magnaflow exhaust i have on the truck. is fdm all one unit? so just simply dropping the tank and pulling out the old pump and putting in a new one will hopefully solve my problem?

 

Some have tried replacing just the pump. Sometimes it works, other times they have the same problem. It is pricey but you may consider replacing the entire FDM.

For reference:

courtesy of subford

 

Cant find a fdm. Can only find pumps. Direct me in the right direction

 

Available here: Sender Assembly; Includes Pump, Sender, Float and Strainer by Spectra Premium (part#SP2006H)

Listed as a complete assembly for mid-ship 19 gallon metal tank equipped truck.

 

okay. now i know what to get. but which one should i get. i have a 1997 ford f350 xlt long bed standard cab. 7.5 4x4

 

What size fuel tank do you have? Is it plastic or metal?

 

19 gal steel.