3 Dead Fuel Pumps
 

I've owned my truck for about 14 months now, and i've already replaced the fuel pump twice, and its dying on me again. I've gone over the wiring more times than I would like to think about. When I did head gaskets over the winter I replaced 80% of the fuel system, new fuel rail, pressure regulator, and fuel lines to the filter (also new). My truck has an EFI 302 from a 93 mustang, only mildly modded. Both times i've replaced the pump i've bought a fuel pump for a mustang from a local shop.

What causes a fuel pump to die? Especially repeatedly?

Any suggestions on a better replacement?

Any advantage to going to a higher flow rate?

Any thoughts are greatly appreciated!

-rob

Could the return line be plugged? The pump would work overtime trying to send the fuel to engine without free (regulated) return.

Its possible I suppose, it would have to been the two foot section between the where the filter is and the pump, everything else I replaced.

BTW the pump does recieve the proper voltage, and the relay has been checked by changing it out with an identical one, and no change.

It may be receiving proper voltage on the positive side but could you have an intermittent ground ? After 18 years things tend to get corroded.

That is possible. I know last time when I replaced it and I went through all the wiring, I even ran a ground wire directly from the battery to the pump harness, and it didn't make a difference.

Could the intermittent ground cause the pump to die?

Quote : Both times i've replaced the pump i've bought a fuel pump for a mustang from a local shop?

You bought a pump for a mustang and not a ranger.
Could the mustang pump not be sitting low enough in the tank where as the motor is not submerged in the fuel and be overheating ? With the pump motor low enough , the fuel will take away the heat generated .
I may be grabbing at straws here.

I'm using the fuel pump structure for a ranger, that came with this fuel tank, and replacing just the pump with a mustangs pump. So it should be low enough. As for ever heating, I had heard after the last fuel pump that the gasoline cools the pumps, so ever since i never let the gas go below a quarter of tank. Also as for being low enough in the tank, I doubt it only because I have the tank very low in the past so that there was less than a gallon of gas in the tank.

Feel free to keep grabbing straws! I really appreciate it, i'm looking for anything to check and look into so I don't have to do this again.

Well I didn't even make it 3 months with one fuel pump....Truck died earlier today, towed it home. Pump is getting proper voltage, doesn't even turn on.... F-this...

If anyone has any clue why my truck eats fuel pumps please reply...

If you have any suggestions on a different setup please let me know....

I think I found my problem, and i'm posting in case someone in the future ever has a similar problem. First piece of advice never buy a vehicle where someone else did the initial drivetrain swap, b/c i'm sure they screwed something up. In my case they did absolutely NOTHING right. So after getting several wiring diagrams and a very sore forehead, I figured out the fuel pump relay was wired completely wrong. The inertia switch is being completely by passed, the ignition signal and the test power wires were reversed, and the real problem was the 12 volt power supply was being fed off of the EEC relay which was supplying 6 volts or less.... So the fuel pumps have been running at a lower voltage and have been frying themselves because of it. I now have all new relays and have a constant 12 volt power supply running to the fuel pump relay. The truck is starting and running again, and I have better fuel pressure at the rail, go figure.

Excellent!

What you report.. is in keeping with what the Lightning guys run into. The high speed relay goes out and then the motor either goes too lean and/or the pump burns itself up.

Rich