Hi Guys

Have a quick question which someone can hopefully answer for me.

I have a '96 F250. Just restoring it underneath from back to front. I'm sanding everything and coating with POR15, I replaced rear tank and straps and now just finished up the front tank. Both were leaking a bit due to rust. I've had no problems figuring everything out myself so far.

My recent problem is that my front tank started spewing due to part of the seam giving way on front tank. Even when I had it switched to the rear tank it was leaking gas from the front tank. I had about 9 gallons in it at the time it began leaking. Right before it started leaking I was driving and was running off the front tank. Truck started putting and died like I ran out of gas. Switched to rear tank and she is fine. Same day I see front tank leaking as I am on the rear tank. Saw the seam split where it was leaking, drove home and parked it.

Fast forward to this past weekend. I just got finished sanding the rest of the frame and coating with POR15 after I had nice amount of access under the truck with the old tank removed. I got a new fuel strainer for the bottom of the pump/sending unit put it back in the new tank and installed a new ford fuel filter while I had all that access under the truck. Put it all back together. Put 4 gallons of gas in yesterday, switch to front tank and what do you know. Truck starts putting and stalls. Obviously the pump or sending unit is bad. So how do I determine which part is bad and can I replace just part of the unit or do I have to buy the whole damn thing for $250-$300? I want to make sure I do it right the first try as I have to drop the tank again, not the end of the world but its freezing ***** in CT right now so I dont want to have to do this again twice. Not to mention i have fuel in the tank now so its not as easy.

As always, thanks for any advice and pointers!

George

 

So the truck would not run on the front tank and then it started leaking from rust?

You put a new tank and only a new strainer on the old pump? Oops. I'd guess the pump was junk when it quit running BEFORE you took it apart.

Personally I would never replace just one piece of those assemblies. Especially when it takes so much effort to get to it. Do it all and not have to worry. Just did the rear tank on the '95 F250 at work. Same thing, rusty and started to leak. Bought tank and new pump assy to put in. After near 20 yrs there is no sense in using old parts.

At least you can run on the rear tank til the weather breaks and you can drop the front again.

 

I was using the front tank when the truck died while I was driving. I switched to the rear and it was fine. When i got to the grocery store and smelled gas I looked under the truck to see the tank leaking a decent amount of gas. Thats when I noticed it was leaking at the seam. I figured maybe the lack of pressure in the tank had something to do with the tank and/or pump not working.

When I replaced the rear tank over the summer the pump/sending unit looked fine so why would I replace it? I figured same for the front. I guess part of the unit is no good and would make sense because since I've owned the truck brand new in 96, I've mainly only used and filled the front tank so it got the most use. I only have 105k on the truck and I've taken care of it so didnt think I would have to replace the pumps or was aware this was a part that failed after only 100k miles. Guess its common?

Its not that hard to drop the tank after you do it once, add a new one, and coat the bolts with anti-seize.

If no one can determine what is wrong with the unit that goes into the tank I guess I will have to buy a whole new one. I am a guy who likes to fix things rather than buy new if I can avoid it. Something tells me this unit can be taken apart and whichever part is failing can be replaced. Its plastic and metal. Only the mechanics fail. The rest of the unit doesnt go bad. Know what I mean?

 

Check the wiring where it plugs into the rear tank. There has to be a reason plug-ins are available. Also relay for pumps, selector switch and inertia switch. My 460 has an oil pressure cut-off switch - don't know about yours.
Thinking it over, I'm confused. Are you having trouble with the rear tank or the front.?

 

My problem right now is with the front tank. Not getting fuel out of it because when I select it the truck dies. Rear works fine.

The front tank cable with harness off the sending unit/pump just plugs into a piece in the frame which is coming from up front on the truck. Doesnt go anywhere near the rear.

Where are these relays for pumps and selector switch? Under the hood in the fuse box? How can I tell if they are dead?
My guess if the relay was bad for the selector switch the front or rear wouldnt work right?

 

I'm going by my 87 which might be different. 87 relay is mounted on the inner fender near washer/overflow jug. If rear is ok, the relay should be ok. Possible selector switch on dash.?
I'd check at the pump connection to see if there is current to the pump. 4 wires ( 2 are grounds, 1 for sending unit/gauge, 1 power to pump. Not sure about the colors. There was a great trouble shooting thread on here a few years ago. Thought I bookmarked it...guess not. Using an ohm meter you should be able to figure out the grounds. Key on one of the 2 remaining wires will be hot (fuel gauge should read full with wires disconnected) Ground that fuel reads empty. With fuel injection, when you turn key on pump will run briefly then shut off until engine starts. You can check this by having a helper turn the key on or with a long test light leads or a voltmeter. Yes, current bad pump, can always run a hot lead from the battery to the pump to check. No current, now back to dash switch.

 

A 1987 truck has a completely different fuel system than a 1996 including no oil pressure switch as well.

 

The front and rear tank share a common Fuel Pump relay. Which pump gets the power is determined by what position the Fuel Selector Switch on the dash is in.

Read through this thread: https://www.ford-trucks.com/forums/1...k-problem.html

The 1994 trucks have the same fuel system as your 1996. Subford has some great photos and directions.

The fuel over-flow is caused by a faulty check valve in the front tank Fuel Delivery Module. I am not certain if you can just replace the pump to fix the issue.

 

Thanks Randy,

So it would probably be a good idea to replace the entire unit un the front tank (sending unit and pump) as one piece. Looks like a spectra replacement from rockauto goes for about $135. The Motocraft one is $300. I think Im going with the spectra.

When you say the fuel over-flow is caused by a faulty check valve do you mean the overflow from the rear tank to the front tank?

If this valve is bad can I still drive the truck using the rear tank or is the gas going to be sent from the rear tank to the front tank and cause me to run out of gas in the rear tank quickly?

 

yes the front tank check valve is bad.


Yes the rear tank will continue to fill the front tank therefore the rear will run out quicker.