rear tank fills front tank
Thread Starter
|
New User
Joined: Mar 2010
Posts: 4
Likes: 0
From: South Austin
rear tank fills front tank
Hi all,
I just joined this forum because I have a problem I cannot diagnose myself. When running on my rear tank, gas is pumped into the front tank. I know this because I always use the entire front tank first, then I switch to the rear tank. Well, lately, my rear tank has been coming empty sooner than expected by 50 miles or more. I then switch to my front tank which should be empty, and it's not.
A problem that I think is unrelated is a lean fuel/air mixture code from both banks. I have tried to fix this by cleaning the MAF sensor. I don't know if it worked or not. I think it's also possible that my fuel tank issue is causing low pressure in the fuel rail which would also possibly cause a lean condition.
The truck is a '96, and I don't believe this year had a selector valve. I guess there must be a check valve in whichever pump is not active to prevent fuel from the returning to the inactive tank. Is this correct?
Please advise if you have any experience with any of this.
I just joined this forum because I have a problem I cannot diagnose myself. When running on my rear tank, gas is pumped into the front tank. I know this because I always use the entire front tank first, then I switch to the rear tank. Well, lately, my rear tank has been coming empty sooner than expected by 50 miles or more. I then switch to my front tank which should be empty, and it's not.
A problem that I think is unrelated is a lean fuel/air mixture code from both banks. I have tried to fix this by cleaning the MAF sensor. I don't know if it worked or not. I think it's also possible that my fuel tank issue is causing low pressure in the fuel rail which would also possibly cause a lean condition.
The truck is a '96, and I don't believe this year had a selector valve. I guess there must be a check valve in whichever pump is not active to prevent fuel from the returning to the inactive tank. Is this correct?
Please advise if you have any experience with any of this.
Lead Driver
Joined: Nov 2002
Posts: 9,557
Likes: 44
From: Concord, NC
There is a check valve in each tank. It sounds like the one in the front tank has failed and is allowing fuel from the rear tank to cross over, which could contribute to the lean codes, as you suspect. The fix is to replace the front tank fuel delivery module, which includes a pump, shuttle valve assembly, and fuel level sender. I have read that you can get the shuttle valve(s) as a separate piece, but I've never looked into that with much detail since my truck did not use that set up.
Thread Starter
|
New User
Joined: Mar 2010
Posts: 4
Likes: 0
From: South Austin
There is a check valve in each tank. It sounds like the one in the front tank has failed and is allowing fuel from the rear tank to cross over, which could contribute to the lean codes, as you suspect. The fix is to replace the front tank fuel delivery module, which includes a pump, shuttle valve assembly, and fuel level sender. I have read that you can get the shuttle valve(s) as a separate piece, but I've never looked into that with much detail since my truck did not use that set up.
Thread Starter
|
New User
Joined: Mar 2010
Posts: 4
Likes: 0
From: South Austin
I think I need to replace the fuel pumps on both tanks. I could probably get by just replacing the fuel pump on the front tank, but I think that both shuttle valves are probably affected based on what I've read. Is the easiest way to do this removing the bed?
Which auto parts store is best for buying fuel pumps? It's not clear to me which pump is for which tank when I try to buy pumps online from Advance or Napa. Does anyone have any advice on this?
Which auto parts store is best for buying fuel pumps? It's not clear to me which pump is for which tank when I try to buy pumps online from Advance or Napa. Does anyone have any advice on this?
Thread
Thread Starter
Forum
Replies
Last Post
Ex-ChevyOwner
Fuel Injection, Carburetion & Fuel System
2
Oct 7, 2015 09:14 PM
eds72
1987 - 1996 F150 & Larger F-Series Trucks
5
Jul 14, 2015 08:25 AM
SSellers
1980 - 1986 Bullnose F100, F150 & Larger F-Series Trucks
20
Dec 24, 2013 12:47 AM
lud04X
1994.5 - 1997 7.3L Power Stroke Diesel
8
Dec 3, 2011 09:58 PM
