1988 Ford Motorhome 1987 E-350 electric fuel pump problem

Have you checked for voltage at tank ?
have you checked ground at tank ?
There were problems with the plug on top of the tanks on some pickups
I would use a battery and put voltage directly to pump wires and see what happens.
dave

There was a bad batch of fuel pumps a while back. A friend of mine went thru 2 replacement pumps before the third one worked and lasted. The supplier (don't know who that was but google probably does) acknowledged the bad batch and reimbursed him for parts. He had to eat the labor costs, tho.

However, if your symptoms are as noted (sorry I didn't pay more attention to the details above) then yeah, more troubleshooting or detailed description required.

Does the engine not start?
Start then die?
Run for a while then die?

Fuel pressure gauge in-line to verify fuel pressure and pump operation?

Be funny if it was a run of bad pumps.

How much fuel is/was in the tank? Were you able to determine if there was crud in it? Were you able to clean it up?

New pump should have come with a new "sock" to strain the incoming fuel. You installed a new one, right?

I have a possible tip. Please send me a private message.

You are correct 1987 Ford motor is gas carbureted There is but one 36 gallon tank. Here is what I see. The fuel pump relay has 4 pins and 4 wires. #1 pin is black ground #2 is power red/yellow #3. is pump power red (pink)/blk #4 blk/yellow inertia switch. The relay is good and the wires check out as in volts. The inertia switch is not tripped. When I jumpered #3 and #4 to manually start the fuel pump it did nothing. I jumpered the oil pressure switch and nothing. I checked all the fuses in box both sides of fuses with multi meter looked good. I simply can not figure why when the electric fuel pump when first put in tank it starts right up and everything is great. But then it suddenly stops working and that is the end of that pump, (3) times this has happened. maybe my vin number would give you the correct wiring diagram here it is: VIN# 1FDKE30L9HHB83879

OH!!! If vehicle is as shown in the Diagram above, you will NOT hear the fuel pump when you simply turn the Key to Run. Look below the words "7.5L Fuel Tank Selector" and you'll see "Hot in Start or Run" BUT the power has to run through the Oil Pressure Switch. Not started yet, no Oil Pressure, no Power to Pump. Through THAT path, that is. Now look to the right of "Selector" and you'll STARTER RELAY. That's the solenoid inside the fender well. On ours, it was on the passenger side right by the battery. Should be a Light Blue Wire on that Relay. That wire should show 12VDC when the Starter is engaged. Its job is to fill the Carburetor while the engine is cranking so there's gas there to start on. Once running, you release the Key to the Run position. The Starter Relay drops Open but the Oil Pressure Switch Closes, and power to the pump is restored, but through the Resistor. Many of us have run a pushbutton to the Blue wire so we could fill the carburetor before cranking. Much better starting that way.
But First!!! We need to confirm that your E350 is set up as shown in the Diagram.

First, Welcome to RV.net!

This E350... 460 engine? How many Fuel Tanks? As in One or Two Fuel Fillers on the side of the coach? Is it Carbureted or Fuel Injected?

My recall is that a 1987 would still be Carbureted and probably has only One Tank.

If what I said above is true, then there's a "run resistor" powering the fuel pump. Here's a diagram.



In the upper part of the diagram there's a ".75 Ohm Resistance Wire" between the Cutoff Relay and the Select Relay. This assumes a Two-Tank chassis, but the Resistance Wire would be there in a One-Tank also.

The Resistor is bypassed when the engine is being started, and reduces voltage to the pump while driving. Still, running on full system voltage shouldn't burn a pump out in HOURS let alone minutes.

Do you know if anybody's modified the wiring?

we have had a problem with our front tank fuel pump. Not working after a few months in hot conditions, Replaced three pumps in four years. New mechanics this time discovered a fine grit in the front tank. Looking further they discovered small cracks in the rubber fill line and vent line. What they think has been happening is that those small cracks allowed very fine road dust to get into the tank. We have flushed the tank replaced the lines and fuel pump time will tell but hope this solves the problem. Now a little background from what I have read the fuel system in this era of Ford E series were major pain in the @ss, They are very pressure sensitive meaning that the least bit of reduced pressure from the pump shuts the fuel system down. Some people have installed after market pumps and pressure regulators between the tank and the engine.

It is fuel pump in tank I turn key on and pump does not activate

Now hold on a minute, in the original post he said FUEL pump, so is it for the Fuel or the Water.

The electric fuel pump acts like it is not receiving power however 12 volts is being carried to the pump. What would burn up a pump with in 5 t0 10 minutes this is the third pump I have installed. following items have been check and or replaced, The inertia switch, the fuel relay the oil pressure switch, fuses on both sides. I am absolutely lost now. I have checked all wires.