Fuel pump issue

[minidude147]

I know this has been Discussed already, however I didn't seem to find a solution. Ever since I replaced my stock fuel pump with the deatchwerks 340lph I've been having issue with My gas running out with around 5 gallons in the tank. I then bought a cheap ebay fuel pump with sending unit because I thought it might be my sending unit and I am still having the issue. I ensured the crossover tube was connected any thoughts? It is an 06 mustang gt. Thanks for any help.

 

[Dino Dino Bambino]

I'm not sure I have a clear understanding of your problem. Are you saying that you actually run out of fuel when the gauge is still showing just above 1/4, or is there actually 5 gallons of fuel left in the tank but the fuel pump doesn't pump it?
If it's the former, it's possible the gauge stepper motor is at fault and giving you a false reading. If it's the latter, on which side of the tank is the residual fuel?

 

[minidude147]

Last time I ran out of fuel I opened the passenger side and there was fuel left in there, I ran the car to where it died.

 

[07 Boss]

Double check your crossover tube. I had this issue once and the tube looked like it was attached but was not seated all the way. I mean it works as a siphon, if I remember, and no actual pump so if the fuel is not crossing over it can only be pretty much that.

 

[AHaze]

Had the same issue last year. Crossover tube had a leak in it so once the fuel level got below the tube, it just sucked air. I couldn't find the leak but replaced the tube and no more running out of fuel with the gauge showing 1/4 tank.

 

[minidude147]

Okay maybe I'll replace the tube it sounds like my issue because it still is sucking some fuel from passenger side, I'll just have to find the part number for that. Thanks for all the help everyone.

 

[Laga]

Double check your crossover tube. I had this issue once and the tube looked like it was attached but was not seated all the way. I mean it works as a siphon, if I remember, and no actual pump so if the fuel is not crossing over it can only be pretty much that.

It’s not a siphon. It draws fuel by a Venturi on top of the fuel pump tubing.

 

[minidude147]

Does anybody know the part number for that fuel line or can I use a custom one, the ford dealer couldn't find it in their diagrams.

 

[AHaze]

I just replaced it with submersible rubber fuel line. Carved some barbs into the plastic bits the hose connects to and used stepless clamps to secure it.
You have to be careful where the hose wants to sit as it could interfere with the fuel level floats. Probably best to use a few brass 90° fittings to emulate the shape of the original tube but I didn't think of that while I was doing the repair. Haven't had any problems so far. Fingers crossed.

 

[minidude147]

OK thanks sounds like a plan

 

[07 Boss]

It’s not a siphon. It draws fuel by a Venturi on top of the fuel pump tubing.

Yeah, well venturi refers to the principle involved in using flow to increase or decrease pressure through velocity where technically a siphon uses atmospheric pressure difference. Either way its the tube that sucks gas from one side to the other by pressure difference.

 

[minidude147]

Just an update I made a custom crossover line and changed the fuel sending unit and the issue is resolved. When I originally swapped just the fuel pump I must have damaged the line and sending unit.

 

[JC SSP]

Great info. Did you take any pics?

 

[minidude147]

I did not sorry. I just bought 5 feet if 5/16 inch fuel hose and 2 90 degree disconnect with a 3/8 female and 5/16 male end