I've seen a lot of dual tank stuff, but not this one. Hopefully someone can shed some light on this.
1988 F250, 300 ci, 5 speed manual. First of all, the gas gage is always pegged high. Doesn't matter if front or rear tank is selected. Second, only front tank provides fuel. Doesn't matter which tank is selected. I even went so far as to pull the connector on the selector switch off---no change: vehicle still ran and fuel still pegged high. The gage itself is not stuck, it can be pulled off of top stop with finger. My current MO is to just fill the front tank every 200 miles, but I'd rather have the flexability to use either tank, and to know the level in the selected tank. Thanks in advance.

 

Hi RW

If you can find a "Haynes" 80/96 Ford truck repair manual it will show parts your need to know about. Also testing specs.

Althou mine was 88 w/460, I think parts are same. Mine had efi, so I'm assuming yours is also fuel injected. If so....

Others have similiar unit, but f.i. will have what's called a "Dual function reservoir" Located under d. side on frame rail. You'll see the fuel lines going to it. If bad, can't switch tanks.

The DFR can be tested but has no repairable parts. Also......

Chances are you have a bad (for fuel level) sending unit. It is part of the e.pump, and there is one in each tank.

I had bad sending unit, but not a switching problem. I replaced that dfr unit as preventive maint. because trk. was 9yrs old w/98K mi. Dont forget to chg. f.filter if needed.

Good luck on fix.....OT

 

Thanks OT

You've given me a place to start. Yes, I do have EFI.

So assuming I replace pump and sender in rear tank and dfr, that should fix my inability to pump from the rear tank.

What about level indication in the front tank? I'm able to draw off of that tank now, but level indication never decreases. Is it possible to have a good pump with a bad level sending unit? If so can just the sending unit be replaced or is it a package deal--pump and sender? Thanx

 

The manual tells how to test the "dfr" w/air. Otherwise you could just replace that part and see what happens? Dont recall it being electrical, so could be returnable?

The e. fuel pump/sending unit are together. I got it from local ford parts, along w/the dfr. They didnt show separate parts, even thou I only needed the sending unit.

Just as well, because of age/mi. on that trk. Shortly after I did rear, front s.unit went out, pump still good. Strange eh! Gotta pay attention to how much gas you got.

OT

 

I replaced the fuel pump in my '88 F-150 and the sending unit/float was a separate unit and not replaced. My pump burned out from being ran dry. Once upon a time I let the tank run completely dry and when the engine started to die, flip the switch to the other tank. I didn't realize that pump ran dry for ten miles or more. LOL!
1. Gauge pegged out - sending unit
2. Not switching tanks - selector on the frame rail with many lines to it, or bad switch?
3. Still running when other trucks would send you walking - Ford Tough.

 

Thanks for the great input guys. I'm gonna wait till it's a bit warmer and tackle this job.

I see that I can drop the tank or remove the bed, I think I'll try the drop tank method since I will only be fixing the rear tank at first.

Last question--should I go with ford parts (no doubt at greater expense), or go aftermarket? Advance auto on line has brands like master, carter, and niehoff.

Thanx again. RW