When I park my truck facing down hill after an hour or so it will start hard. If I bump the starter and let the pump run for 10 seconds it will start. If I park it facing down hill it doesn't lose prime and starts right off. Condition gets worse if the tank is less than 1/2 full. Injector pump is just over two years old with 52,000 miles.Twogun

 

Sounds like an air leak. Since you replaced your stock fuel system with a FASS, I would start there.

Dave

 

Just some guesses - check valve on the return line - side of the VP44. Bad starter -mine was hard starting due to slow cranking - new starter fixed that. Lift pump? Hows pressure? Cracked lines? Loose fittings? Plugged fuel filter?

Not all specifically for your symptoms but could be worth checking.

 

The overflow valve is not an issue with the VP trucks.

Well it can be, but it has an air bleed hole built in. So, it will always lose prime.

The pump should be holding prime. If it's not, there's an air leak elsewhere. Is there any fuel on anything??

Dave

 

My FASS was loosing prime also, and it got worse as the tank got lower. I contacted them, actually on here, and was told about an updated pump and T-block that helped. Still not perfect, but reprimes faster than before.

Chris

 

Starter is original with 138,000 plus but still spins like new with new batteries. Fass pump was replaced 6 months ago, bad brushes with no way to replace one side due to plastic caps breaking down. Problem did start after it was replaced, maybe an air leak somewhere. It doesn't happen if the truck is pointed downhill and does get worse as tank is drawn down. Twogun

 

Did we already mention the suction tube may be leaking in the tank?

 

When fueling the pump shuts off and if I try to top the tank off with anymore fuel it spills out of the top of the tank where the fuel gauge and draw point enter the tank.

 

Mine did that too- previous owner put the unit in crooked - 6 inch dia screw ring wasn't on right. Also vent didn't have a hose so I put one on and extended it up the side of the filler neck - appx 1/8" line - I used black plastic drip irrigation tubing.

 

TwoGun,,, any fix yet.

I have replaced everything from tank to VP, new LP, new 3/8 fuel line, new 2001 fuel filter housing, intalled an under hood pre filter pressure gauge. removed an checked the VP return check valve, Fishin2Deep4U is right, there is a small hole built into them so no way they can ever keep prime.

Next for me is replace all return fuel line, then remove and check the injectors and the little rubber o rings, then i guess a new VP...

When someone figures this out, please post in a sticky..

 

I replaced the return fuel line from the VP overflow valve to the T. Put air pressure to it and found a small pin hole at the banjo fitting. Replaced the line and truck starts like it should......