Hey Guys, First off let me introduce my self, My name I Juan, I own a 1992 F250, Ext Cab 4x4 with 143,xxx Miles 7.5 gas engine and I LOVE my truck.

As I am driving to work, just 1 block from parking, I notice a gas smell, and think uh oh, I look at my gauges, and all looks good, (normal any way, My truck has 2 tanks, the front tank's sending unit does not work so it reads empty, but the pump works) so I decide to just drive the extra block and get to work. (bigger/safer area to look around for the possible gas leak)

As Soon as I get out of my truck, I see what the problem is... there is gas SPEWING from the rear gas cap. and I mean a lot! Again, two tanks, the rear tank works 100%, sending unit works and reads on the gauge cluster, and the front tank, the pump works, just does not show how much fuel it has on the gauge cluster.

Here is how I have been driving it. Fill up both tanks... Use the front tank first, when it starts to die, then I switch tanks and then I know how much gas I have and when the gauge shows low, I fill up both again. I know its not the best thing to do for the front tank, but I figure I dont really care if that pump goes because it would be the perfect time to fix the sending unit problem any way.

So as of today, as I was driving to work, my truck was using gas from the front tank, and it's pretty full, I just filled up last night, and out of no where gas is shooting out of the rear gas cap. I went to loosen the rear gas cap, just to see what would happen, see if the pressure would settle down but it seemed like it would just continue to push out all the gas. I am hoping some one can tell me what the heck is going on?
What would cause this to happen?
How do I fix it?

PLEASE help me out!

As of now I'm thinking of having my truck towed home, but would really like to know what I am getting into!

Thanks!

 

I believe your reservoir has gone bad. The reservoir is responsible for switching between tanks and it is usually at fault when you get fuel transferring from one tank to another:

https://www.ford-trucks.com/forums/4...tor-valve.html

 

Oh? A reservoir? Do you know where it should be located? best way to get it fixed? as in how to get to it, and where to buy?

 

Ford stopped using the reservoir/3-pump system in 1989. The OP's truck uses a high pressure pump assembly in each tank.

The rear tank has a bad check valve in it, that is why the front tank is filling the rear.

From subford:

 

RLA2005,

That makes a little more sense to me,

by the looks of it, I think I am stuck replacing the whole intake fuel pump system hu?

If that's the case, I might as well just drop both tanks and replace both fuel systems.

 

Since you already have a problem with the front tank sender you might as well bite the bullet and fix both issues.

 

this is an old post but im hoping somone can also help me with a similar problem. my front tank fills up from the rear tank, is it worth fixing as long as i don't get the front tank to full? also when i start the truck with the front tank, it takes a little while to start up and it idles rough for a few seconds but is fine when driving down the highway. Im low on money as i am in college but it doesn't seam like a problem worth putting the money into right now, maybe this summer. by the way its a 95 f250 300 inline 6

 

Old? It was started this morning.

 

ahh **** i was looking at the wrong date haha

 

Only you can decide if its worth fixing, but for what its worth I had one that leaked bad enough that fuel pressure at the rail was down and the truck started losing power.

 

If you can live with it, sure, just use the tank with the bad FDM first so you don't pump your gas out on the ground. It'll let you know when you HAVE to fix it.

 

Nothing special'so got it right, my sig truck has a bad check causing the rear tank to fill the front. Cheap fix...I drive on the front tank until I'm at 1/4 then switch to the rear until I'm at a 1/4 them make sure I hit the pumps with 1/2 a tank in the front

 

am i able to just replace the check valve or do i have to replace the whole FDM? How much is it for the FDM?

95 F250

 

I replaced both pumps at separate times. The front tank was dropped with the bed on. The bed was removed for the rear one. I HIGHLY recommend removing the bed. Eight bolts and unplug the rear tail light wiring harness. It's so much easier. I bought both pumps from Global Automotive on Ebay for around $40 each. the front was about five years ago and the rear about three. I have been happy with both of them.. It's just the pump, so you have to cut/splice the wiring to the old sending unit.

'96 F150

 

so im just replacing the pump and thats all? i dropped the front tank this summer to replace the breather tube and that was pretty easy. right now i just keep my eye on the front tank and don't let it get full. as for the starting problem i just use the rear tank so i think for now ill be fine but since winter is here it may be worth the $40 to fix it now. when will i know that it absolutely needs to be replaced?