Fuel Issue
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Trailering
Joined: Mar 2020
Posts: 18
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Fuel Issue
Hello All,
1994 F250 300 i6 Cyl. 149k miles. When switched to the front fuel tank, the engine is getting fuel and running normally, but fuel is also being pumped into the rear tank and spilling out the fill mouth. Is this a problem with the tank selector valve or a return line? Thoughts? Thanks.
1994 F250 300 i6 Cyl. 149k miles. When switched to the front fuel tank, the engine is getting fuel and running normally, but fuel is also being pumped into the rear tank and spilling out the fill mouth. Is this a problem with the tank selector valve or a return line? Thoughts? Thanks.
Fleet Owner
Joined: Oct 2005
Posts: 20,786
Likes: 1,751
From: Kentucky
There is no tank selector valve on 1990 and up gas engine trucks. Each tank has it's own Fuel Delivery Module (FDM). What you describe is the VERY common fuel crossflow issue these trucks are prone to do. This has been covered hundreds of times on this forum. The tank that is getting filled has a bad check or shuttle valve. The fix is to replace the entire FDM. Some have tried installing the bad-aid recall fix by installing an external check valve in the fuel supply line of each tank. Mixed results because it only fixes a bad internal check valve, not the shuttle valve on the return port.
Here is a breakdown of the Fuel Delivery Module
Here is a breakdown of the Fuel Delivery Module
Thread Starter
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Trailering
Joined: Mar 2020
Posts: 18
Likes: 0
Thank you for your help.
That sucks...I replaced both fuel pumps last year. Maybe still under warranty.
But to clarify, the problem is with the FDM in the rear, not the front tank that the switch is set to and is pumping? When the switch is set to the rear tank, I don't lose fuel out of it and it draws down normally. When I switch to the front tank it empties fuel into the rear. So the problem is with the rear pump?
That sucks...I replaced both fuel pumps last year. Maybe still under warranty.
But to clarify, the problem is with the FDM in the rear, not the front tank that the switch is set to and is pumping? When the switch is set to the rear tank, I don't lose fuel out of it and it draws down normally. When I switch to the front tank it empties fuel into the rear. So the problem is with the rear pump?
Fleet Owner
Joined: Oct 2005
Posts: 20,786
Likes: 1,751
From: Kentucky
That is correct.
But to clarify, the problem is with the FDM in the rear, not the front tank that the switch is set to and is pumping?
"The tank that is getting filled has a bad check or shuttle valve.
When I switch to the front tank it empties fuel into the rear. So the problem is with the rear pump?[/QUOTE]
That is correct.
But to clarify, the problem is with the FDM in the rear, not the front tank that the switch is set to and is pumping?
"The tank that is getting filled has a bad check or shuttle valve.
When I switch to the front tank it empties fuel into the rear. So the problem is with the rear pump?[/QUOTE]
That is correct.
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