Hello all. I'm new to the Ford truck world, and was hoping I could get a little help with my truck situation. I bought a 95 F-150 XLT 4x4 (supercab, longbed) earlier this year, and I was told at the time that there was a transfer problem between the fuel tanks Upon crawling underneath, I found that the lines just forward of the rear tank have been cut, plugged and clamped, and it looks like someone drilled a hole in the rear tank to drain it, and then plugged it (it's the steel tank). I'm planning on replacing the rear tank and pump, but I'm wondering if anyone can guide me towards what else I might need. Are the fuel lines special fit or just cut and install? Is there some sort of selector valve that needs to replaced as well? Thanks in advance!

 

Ouch, I hate to know some *** of an owner cut the Stainless Steel flex lines with special slip fit ends. That is definitely a hack job.

I know the OEM lines can't be purchased, but perhaps someone else can direct you to a fix.

 

It was originally a commercial truck with an illuminated CEL that the owner just didn't want to deal with anymore, so I got it for a song. It turned out to be a simple EGR sensor. The downside is that it was a commercial truck, so nobody really cared about it.

 

No there is not a selector valve.

As for the fuel lines either get them from a salvage yard or connect the back tank to the fuel lines with high pressure fuel injection hoses with double FI hose clamps.

Attachment 280308

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Thanks! This should help quite a bit!

 

My 95 F-150 has developed a problem that started when I filled both tanks, I could smell gas for a couple of days I was flipping from tank to tank and adding additive since I had recently purchased the truck and was unsure of the quality of fuel in the tanks. It was hard to start on the rear tank so I used almost all of the fuel and planned to drop that tank and inspect same. The other day I noticed the gas gage on the front tank was showing less gas than I thought it had. Thinking I was nuts I again filled the front tank(10 gals.). I drove 5 miles shut it off for 25 minutes came out and started the truck, a friend approached and we talked for 2-3 minutes and then I noticed gas running out the rear tank fill door. The front tank is now down almost a half a tank and the rear is overflowing??? Any ideas??

 

If I'm not mistaken, the check valve in the rear fuel has failed. I am in the process of the same with mine. I put a new fuel pump in the front in July and walked outside a few days ago and fuel was pouring out the rear filler cap.

Here's a link I found.
https://www.ford-trucks.com/forums/1...-up-front.html

 

Thanx for the advise. Check valve seems a likely candidate.

 

I have as advised replaced the rear tank fdm and on further discovery find that which ever tank I'm drawing fuel from the return is going into the other tank. Both front and rear tanks are doing the same thing. I am too old to try repairs in the drive way so my trusted mechanic is doing he repairs. We are not sure if there is a valve involved to divert fuel from one tank to the other. None was noted when the rear tank was dropped to replace the fdm. If there is a valve could the return lines be reversed? Where is the valve located, if one is present? Thanx.

 

Very possible that the "NEW" pump is defective. Many threads on here with members installing new fuel pumps and they fail Right out of the Box.

 

The valves are all inside the tanks and inside the FDM for your 1995 F150.

The FDM:
Attachment 281295

The Fuel Delivery Assembly all so called the FDM (Fuel Delivery Module) consists of the fuel pump inside a reservoir that is attached to the pump and sender assembly. In a two tank system there is one assembly per tank. The FDM handles the switching of the fuel through internal valves. To service the assembly, replace it.

Fuel reservoirs are used to prevent fuel flow interruptions during extreme vehicle maneuvers with low tank fill levels. The reservoir is located in-tank and is either molded or welded into the tank or is part of the FDM.

The fuel filter assembly is located between the fuel pump and the Schrader valve or injectors. This filter should be serviced periodically by replacing it.

The Shuttle Selector Valve opens the return line to the tank when the fuel pressure on the shuttle diaphragm exceeds the opposing spring force. The return flow is directed to the appropriate tank on vehicles equipped with dual tanks.

The Supply Check Valve, which is normally closed, opens when the outlet pressure from the energized pump exceeds the opposing check valve spring force. When the pump is de-energized (i.e., engine is shut off), the supply check valve closes to maintain pump prime and fuel supply line pressure.

A portion of the high pressure flow from the pump is diverted to operate the Venturi Jet Pump. The Venturi Pump draws fuel from the tank into the assembly. This process ensures an adequate fuel supply to the pump during extreme vehicle maneuvers and steep vehicle attitudes with low-tank fuel fill levels.

The inlet of the Venturi Pump has a nylon filter on it to prevent dirt and other particulate matter from entering the system. Water in the fuel tank can pass through the filter in small quantities.





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The check valves are located inside the fuel delivery module (FDM). There is a FDM inside each fuel tank. I believe your issue is that the check valve in the front (side) tank is the defective valve. What happens is that when you use your front tank, fuel is sent to the engine. The return line sends the unused fuel back toward the front tank, where it should flow back into. Since the check valve is defective, the fuel cannot enter the front (side) tank and continues on to the rear tank. The rear tank keeps filling, until it overflows.
I have attached the fuel tank/lines section of the 1996 service manual for your convenience. You can see on page 10-01A-4 the fuel line routing.

 

Thanx for the diagram it helps. I think the problem is that the return lines are crossed since both tanks return to the opposite tank (front to rear, rear to front) and I have replaced the rear FDM with no change. The problem with that is that appears there is no joint in the return lines that would allow for that to happen. I'm reluctant to change both FDM for economy reasons, since changing the rear has made no difference.

 

There are no valves in the return line. The return line valve are in the tank (FDM).
So you can not cross the return lines.

 

Kinda knew it wouldn't be an EZ fix. I have no idea what the problem is, but I can't believe I'm dealing with 3 bad FDM. Original 2 and 1 replaced. I may just pull the bed and trace the lines. This truck has 235,000 miles, but has a new Jasper engine and rebuilt transmission, and previous owner said he hadn't used rear tank for awhile. I'm right now running a test to see how far I have to drive to fill opposite tank. going to go both ways. Thanx for the help, and MERRY CHRISTMAS TO ALL!!!