Thread: Fuel supply problems! v8

Also it is EFI with wolf 3D engine management (which appears to be fine)

Fuel pump relay? change it.
Bad connections in power supply to pump,. Hot wire it.
Fuel filter blocked? fit new.
Regards Philip A

I just disconnected the fuel hose at the fuel rail connection point and stuck the end in a coke bottle and turned it over, seems to be a reasonable amount of fuel being pumped through although not sure how much there should be.
The connections were a bit crapped up but cleaned them and seems to be fine - pump turns on and off with relay clicks.

Just done another check and the fuel pump keeps running once I stop cranking and the engine is running and for a second or two after the engine splutters too a stop.

The engine runs for a bit longer if I prime it (key to ign position then off) a couple of times before I turn it over.

Could the pump not getting a good 12v supply cause this? If it was a bad connection and it was getting enough voltage to run, but not run fast enough?

You really need to tee a pressure gauge into the fuel line or something similar. My guess is that the pump isn't producing any pressure due to a loose hose or similar on the pump inside the tank. You may have to remove the pump assembly, immerse it in a 2 litre container of fuel and observe the pump. The hose between the pump and the pump bracket assembly must be of the correct submersible type and capable of holding 40psi approx.

The pump assembly is an off the shelf item so I assume the pipe is the correct grade etc. however I have taken it out and compared it to the one that was in there and there is an extra bit on the old one? Anyone know what it does or what it is for?

Old pump black filter, new has white...



Worth moving the new pump to the old assembly?

That is a teeny weeny pump, probably just a carby or lift pump. I betcha it doesn't come even close to EFI pressure. Just purchase a Commodore/universal EFI tank pump kit, e.g. Bosch part number BFP772 and put it into the old pump bracket. I fit this particular pump kit to lots of LR V8 EFI vehicles, it contains new connector plugs, new hose bit and new filter sock.

if its connected onto the main pipe its a dampening chamber.

if its on the end of moving arm its a float chamber.