Zero fuel pressure

[mmvic]

The truck died on me a couple of weeks ago while driving. When I pulled over and tried to restart it my fuel pump didn't prime. I checked the fp gauge on and no fuel pressure. I checked the fuel pump relay and ecm b fuse both good. I tried jumping the pump with the pig tail and nothing. BTW this is a 4 year old walbro pump, and brand new fuel filter.
When I removed the pump I tested it by hooking it up to the battery and it worked. So now I thought it is a bad connection in the sending unit. Bought a new one,installed a new pump and tested to see if it would prime with the key turned. It did, numerous times. Thought the problem was fixed until I bolted everything up and let it idle for 30 seconds... Died again, same problem still, zero fuel pressure, does not prime.
I checked the ground on the frame by the the tank and it looks good same for the one up front under the radiator hose. Fuse and relay are still good.
PLEASE I am stumped and need suggestions on how to track down this issue.

Thanks-Matt

 

[mmvic]

Re: Zero fuel pressure

does the hot wire to the fuel pump go throu the ecm or straight to the pump. Would a bad oil pressure switch effect the pump from responding even when using that hotwire?

 

[jpalmer]

Re: Zero fuel pressure

could be a brand new pump being bad, but take a look at your pigtail near the pump. i had slightly exposed wires on one and when i would push it up they would make slight contact. never blew a fuse, but smoked a couple pumps.

 

[SY2932]

Re: Zero fuel pressure

The fuel pump test connector on the firewall is a direct connection to the fuel pump. If the pump is good it will still run even with the ECM B fuse disconnected... Even though the ground connector on your frame *looked* good, it still may be bad. On my daily driver S10 it broke off when I gave it a little tug when I had to replace mine.

 

[mmvic]

Re: Zero fuel pressure

Figured it out, thank you dave P for your support.
Even though the pump and sending unit are new I reused the wiring harness that connects the pump to sending unit (new one didnt come with one). I kept the hot wire connected and jiggled all the wires and herd it come on when I touched the truck side of the harness. Figures the one thing I didnt change was the broken part. :rotf: