I have a '96 F350, 460 gas, 4X4. I drive it on weekends when I am home. I have only had it a few months. A couple of weeks ago I put gas in both tanks, and was driving it when it started to die as if it was running out of gas. This is the 4th Ford pickup I have owned, so I quickly switched to the other fuel tank. The motor came back to life and ran fine. I have never had a fuel pump go out in one of these things so I am wondering if that is what happened. I am going to check the wiring before I start pulling anything. What is a good brand of fuel pump? I noticed that the Motorcrafts are high dollar. Thanks.

 

Do you still have fuel in that tank? Big problem with the transfer valve or whatever letting the fuel flow out of the tank into the other one.

Other than that after confirming it is the fuel pump that is the culprit, I have never had a problem with the Auto Zone brand fuel pump/sending unit. Had mine in my truck 6 years now. Costs about 112.00 (or did at the time), assuming you have the same one.

 

Yeah, that tank is about two thirds full. I figured the engine draws out of one tank at a time separately. I guess I better study up on this.

 

It does, but there is a crossover valve that has some sort of seals in it that can go bad and allow fuel to transfer from the in use tank to the other tank. I do not have dual tanks so I do not know the issue personally, but if you search on this forum you WILL find it. It has been discussed time and time again.

 

I was thinking tank rust that clogged the tank input? Was this truck sitting for awhile? Does the other tank work for awhile and then just conk out? This is pretty symptomatic of loose rust clogging the intake, then when switched off it just floats back to the bottom allowing the tank to magically work again.

 

Sounds like a bad fuel pump motor in the tank that you were on when it started to die.
So you need to replace the FDM in that tank.
Here is a diagram of your fuel system:


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I had similar symptoms and thought it was water in the gas. Occasional sputtering, poor mpgs. Then I figured out it was the pump starting it's death ritual. So, I just got a whole new tank/pump combo, to save the hassle of extracting the old pump out of the old tank with rusty seized mounting ring. I've done that before and it just wastes a day. I found the tank/pump set for just over $200 delivered, on ebay. The extra hundred bucks was worth it to me, saved a lot of blood, sweat, tears, and time. Now I won't have to worry about the rear tank or pump for the remaining life of this vehicle.

 

That diagram is just what I needed. I'll also look into that tank/pump combo. I have replaced in-tank fuel pumps in Chevys three times, but never had to do one in a Ford.

 

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Just my 2 cents worth but if you do the pump remember the other one is the same age. When mine went it was just getting weak and the truck wouldnt start on that pump but would run on it. The sending unit in the other tank went bad too so I just pulled the bed off. Six bolts and an electrical plug or two and bam bed is lieing in the front yard with both fuel tanks exposed. As said above I too am not a fan of the aftermarkets in this area either so I bought both fuel pumps and both sending units from the Ford house. You'll spend more but if you really depend on your truck then its worth the extra.

 

" both fuel pumps and both sending units from the Ford house. You'll spend more but if you really depend on your truck then its worth the extra. "

You're right, there. My truck only gets maybe 5K miles/year, mainly just for firewood and trash. If my truck was more central to my livelihood, I'd also go with the OEM.

 

Howdy,
THIS IS A 1994 F150!!!

I have a problem with my gas 'swapping' tanks, while running.. I can only put fuel in the rear tank, because if I fill both tanks it will cause the engine to over load and die.. I have found a reservoir in the engine compartment that is full of gasoline and when emptied the engine cranks right back up.. When running on the back tank the gas will go into the front tank and I'll run out of gas in the rear tank.. Also sometimes when climbing an incline, of any angle, running on the front tank, it will began to slow down and sputter; I can switch tanks and it will run just fine, then when I level off I switch back to the front tank and it runs okay..
Somewhere I read about a switch or control, which began with an 'S', that 'COULD' be the problem, but I CAN NOT FIND it on any schematic!!! Do you know what it is CALLED and where it is LOCATED???
The truck runs fine, IF YOU KNOW HOW TO RUN IT, but I'd like to have it fixed!!! It only has 278,000 miles on the 300cid EFI engine and I really like the power it has; it uses NO oil between changes and has ALWAYS had Mobil 1 in it... THANKS, for any info....

 

butterbean,

The "S..." you speak of is called a shuttle valve and is located inside your FDM. The FDM is located inside your gas tanks.

Your problem is that the FDM in the front tank has a bad valve in it and maybe a bad pump also.
This could be the shuttle valve or the high pressure check valve, either one can do this.
So I think if you change the FDM in the front tank you will be good to go.

 

Just a follow up here. Not long after starting this thread I pulled the bed and pulled both pumps. One was doa and the other one still worked. (you gotta be careful jumping those motors with the tanks opened up) The one that worked had no fuel gauge sender attached to it. I bought a junker fuel pump at a junk yard for $30 and used the sender off of it for that pump. I replaced the dead pump with an aftermarket pump from Napa. Everything is working now except that it is difficult to get gas into one of my tanks. When I pulled the filler necks off of the tanks there is a long "inner" hose that extends into the tank. I sprayed silicone lube on them in order to slide them back in, but I must have gotten a kink in one of them. I am probably going to pull that one out and cut it shorter and put it back in.