Gas in vapor cannister, vapor lock?
Thread Starter
|
Junior Member
Joined: Nov 2002
Posts: 2
Likes: 0
Gas in vapor cannister, vapor lock?
Hoping someone can help:
No problems whatsoever with my 1988 F-150 (EFI) until last week. The day after I filled both tanks it ran fine to school but in the afternoon it started fine but idled rough and wouldn't run in gear.
I switched from rear to front tank to no avail.
I had it towed home. The next day I found fuel had overflowed the, what I guess is, the vapor cannister (which I didn't even know I had) and the truck still would start but not run in gear. I tried running it with the fuel caps off thinking one or more bad caps but that didn't helo.
I changed the fuel filter and it seemed to run fine. I drove it around for 10 minutes, satisfied that that was the problem.
Next day it was back to the same problem. I bought 2 cans of STP Gas Treatment thinking maybe bad gas. When I went to put it in the front tank it flowed back out. The front tank was so full it wouldn't take one small can of STP.
I'm thinking some kind of pump or check valve problem maybe creating a vacuum in the front tank which is some how getting fuel from the rear?
Any and all suggestions appreciated. I'm a student and can't really afford to let a mechanic fix it by trial and error!
Thanks
No problems whatsoever with my 1988 F-150 (EFI) until last week. The day after I filled both tanks it ran fine to school but in the afternoon it started fine but idled rough and wouldn't run in gear.
I switched from rear to front tank to no avail.
I had it towed home. The next day I found fuel had overflowed the, what I guess is, the vapor cannister (which I didn't even know I had) and the truck still would start but not run in gear. I tried running it with the fuel caps off thinking one or more bad caps but that didn't helo.
I changed the fuel filter and it seemed to run fine. I drove it around for 10 minutes, satisfied that that was the problem.
Next day it was back to the same problem. I bought 2 cans of STP Gas Treatment thinking maybe bad gas. When I went to put it in the front tank it flowed back out. The front tank was so full it wouldn't take one small can of STP.
I'm thinking some kind of pump or check valve problem maybe creating a vacuum in the front tank which is some how getting fuel from the rear?
Any and all suggestions appreciated. I'm a student and can't really afford to let a mechanic fix it by trial and error!
Thanks
Senior Member
Joined: Mar 2001
Posts: 994
Likes: 0
From: Sparks, Nevada
Hi Stang
As i recall there was a problem with some duel tanks crossfilling. I think their was a fix by Ford...but that was long ago.
Ive changed in tank pumps...but not for problem your having.
If you can find a repair manual Haynes 80-96. Has a good pics/ description of these pumps...FDM (fuel delivery module).
There is one (fdm) in each gas tank...each has a "shuttle valve". The valve maybe stuck open? My guess is that the bad "FDM" would be in the tank that is overfilled---the front tank.
Good luck...OT
As i recall there was a problem with some duel tanks crossfilling. I think their was a fix by Ford...but that was long ago.
Ive changed in tank pumps...but not for problem your having.
If you can find a repair manual Haynes 80-96. Has a good pics/ description of these pumps...FDM (fuel delivery module).
There is one (fdm) in each gas tank...each has a "shuttle valve". The valve maybe stuck open? My guess is that the bad "FDM" would be in the tank that is overfilled---the front tank.
Good luck...OT