Hello guys, new to THIS forum but not to FTE.

I bought a 2003 F550 Super Duty 4WD, cab and chassis truck. It has a 7.3 TD. Real nice truck. I bought it to turn it into a wrecker. I removed the factory fuel tank (was behind the real axle inside the frame rails.) I installed a 50 gallon aluminum tank behind the cab on the frame rails. The rear tank has to be removed for the wheel lift. Any way I have everything installed and now the truck dies out after a few minutes. It starts up fine then dies out like its starving for fuel. The tank I installed has a sump pickup (tank came off a freightliner, so its not some home made thing I just welded up in the garage)

Any ideas? I was thinking about installing an auxiliary lift pump as the auxiliary tank is a bit higher than the factory tank, but I want to solve the issue not throw parts at it.

I thought at first injectors but it runs perfect after I prime it so my guess is its not the injectors.

 

do you have any way to monitor the fuel pressure? that should tell you if it runs out of fuel.

 

I will check in the morning and report the pressure. Question: What pressure should I be looking for? idle or load?

 

No idea, probably depends on which point in the system you are checking the pressure, but just for determining if it's running out of fuel, it doesn't really matter. You'll get a 'high' pressure right off the bat, then watch what happens, if it just slowly goes down, or if it stays at that pressure for some time, then drops. Or it doesn't drop at all.

 

Try running it with the tank filler cap off. If it runs that way then you have a vent issue.

 

I have already tried with the cap off, no change. I am going to test pressure today.

 

I checked the pressure at the pump and i get 68psi. I have not checked the pressure at the filter yet becuase the cheap horror fright pressure tester i bought does not have an adapter to will fit the filter bowl. I will have to go to lowes or ace to buy an adapter. I will report tomorrow the pressure. Thanks again everyone for all of the advice.

 

Did the fuel pressure remain constant while the engine died?

 

does it shut off if you run it with the fuel cap off?

 

it was the fuel pump. Removed the line from the fuel pump and tested pressure there. 70 psi, then today for ****s and giggles i removed the pressure gauge and ran a line right from the pump into a bucket. No volume. I had pressure but no flow. I put on a new pump and truck runs. Thanks everyone for all of the help and advice.