Gas leak
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Tuned
Joined: Feb 2022
Posts: 301
Likes: 30
From: Perth Ontario
As stated previously the unused tank that gets filled, while running on the other tank, has a bad check or shuttle valve. Many of the aftermarket fuel pumps lack the check valve to prevent backlow from the supply line. Since there are two valves in each fuel delivery module that are failure points on this fuel system there can be two different failure modes, i.e. bad/missing check valve (output) or a bad shuttle valve (return)...or both.
Diagram of a Fuel Delivery Module and theory:
Diagram of a Fuel Delivery Module and theory:
The ultra pro at the top is what went in it.
Thread Starter
|
Tuned
Joined: Feb 2022
Posts: 301
Likes: 30
From: Perth Ontario
As stated previously the unused tank that gets filled, while running on the other tank, has a bad check or shuttle valve. Many of the aftermarket fuel pumps lack the check valve to prevent backlow from the supply line. Since there are two valves in each fuel delivery module that are failure points on this fuel system there can be two different failure modes, i.e. bad/missing check valve (output) or a bad shuttle valve (return)...or both.
Diagram of a Fuel Delivery Module and theory:
Diagram of a Fuel Delivery Module and theory:
So this what I need? Do you think i would be ok getting the ultra pro? Then i could put new pump assemblys in both tanks for the price of 1 Delphi.
Fleet Owner
Joined: Oct 2005
Posts: 20,786
Likes: 1,751
From: Kentucky
When replacing just the pump it is a crap shoot whether the crossflow issue will be resolved. If the faulty valve is the shuttle valve the only way to fix the problem is a complete fuel delivery module since that part is not available separately. If you do go the aftermarket pump only route make darn sure the each of them have the check valve on the output side.
Thread Starter
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Tuned
Joined: Feb 2022
Posts: 301
Likes: 30
From: Perth Ontario
When replacing just the pump it is a crap shoot whether the crossflow issue will be resolved. If the faulty valve is the shuttle valve the only way to fix the problem is a complete fuel delivery module since that part is not available separately. If you do go the aftermarket pump only route make darn sure the each of them have the check valve on the output side.
Fleet Owner
Joined: Oct 2005
Posts: 20,786
Likes: 1,751
From: Kentucky
We all feel your pain. As I stated before there are dozens/hundreds of threads regarding the same issue. Sometimes you get lucky with an aftermarket pump only, after verifying it has a check valve. Other times you have to pay the piper.
Logistics Pro
Joined: Nov 2013
Posts: 3,928
Likes: 1,198
From: Mojave, Ca
I just went out and put it on the rear tank because I drove it a little yesterday on the front tank. I let it run for a couple min and it didn't leak a drop. Couple days ago when the front was full to the brim as soon as I switched it to the rear the front would start overfilling and leak.
Logistics Pro
Joined: Nov 2013
Posts: 3,928
Likes: 1,198
From: Mojave, Ca
Find the leak and fix it. Its probably the quick disconnect leaking, not a problem with your FDM.
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Thread Starter
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Tuned
Joined: Feb 2022
Posts: 301
Likes: 30
From: Perth Ontario
there is no leak now that it's not full. It's never leaked before that. After I filled both tanks After getting the rear tank replaced the rear tank leaked out the top. So then I switched to the rear tank trying to get the gas down in the rear tank first because of the leak but then when I got home it was leaking out the top of the front. I drove it for a day on the front then next day let it run on the rear tank for a few minutes and it never leaked. I will go out right now and run it on the back tank again just to make sure.
Thread Starter
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Tuned
Joined: Feb 2022
Posts: 301
Likes: 30
From: Perth Ontario
just ran it on the back tank for 10min no leak
Logistics Pro
Joined: Nov 2013
Posts: 3,928
Likes: 1,198
From: Mojave, Ca
If it was a FDM problem, it would be filling up the opposite tank and begin leaking out of the filler.
Again... Find the leak on top the tank. It's either the quick disconnects or the 5" oring that seals the FDM to the top of the tank.
Again... Find the leak on top the tank. It's either the quick disconnects or the 5" oring that seals the FDM to the top of the tank.
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