Engine/Transmission (1998.5 - 2002) lift pump

[Moe]

I need to know what causes the lift pump to get its voltage to turn on. I turn the key on and sometimes the pump doesnt run at all. I opened up the drain on the filter and no fuel comes out. Keep turning the key on to pump up fuel and eventually it gets power to the pump and fills up and runs fine till the next time. Any ideas?

 

[cerberusiam]

The ECU determines when it runs and how long. Unless the engine is running it only cycles the LP a short time to keep from over pressuring the VP-44 and causing hard\no starts. Just have to keep doing the key on\off or rig a seperate power source to the pump.

 

[JR]

Im not positive about the in tank lift pumps but the original block mounted pumps should not cycle on until you bump the key. At least thats the way my 98 and my 00 have been. The reason your not seeing any pressure at your filter is because as soon as the lift pump turns off, the pressure will bleed back down. The pump will not maintain pressure if it is not running.

 

[NIsaacs]

I would say your lift pump is gunnysacked.

Nick

 

[Moe]

Went out this morning and it fired right off. Went to the store and the tach quit and cel came on. Ran a gauge test and all gauges checked ok including the tach. Checked for codes with reader and no codes set. Fuel pressure stayed at 12 to 13 lbs. Starting to P. M. O.

 

[JR]

Sounds like it could be a crank sensor going bad, but its odd your not tripping any codes. Does your cel come on as a preliminary check with all the other warning lights when you first start your truck?