How much voltage does the fuel pump run on ?

[reflex26]

Can anyone please tell me how much voltage the fuel pump needs to operate properly and also how you check it with a voltmeter at the tank connection?Also the Haynes manual say to remove the tank ground strap when dropping the fuel tank.Does the tank have a ground strap? Does the tank need to be grounded for the fuel pump run? I'm pretty sure I need to replace my fuel pump but want to be sure before I drop the tank.Thanks for any help.

 

[my98nnj]

12 volts

 

[90ranajo]

Can anyone please tell me how much voltage the fuel pump needs to operate properly and also how you check it with a voltmeter at the tank connection?

The fuel pump should be running at the vehicle's system voltage bus of 12VDC +2.4VDC -0.5VDC. If I remember correctly the fuel pump has three wires on it. Ground, Power & Fuel Level Sender.

Also what are the symptoms that you are having?

 

[reflex26]

The truck won't start,It acts like it sure wants to.I cheked the fuel pressure at the schrader valve with a small screwdriver and it has nothing.I have 12 volts at the inertia switch so I jumped it , still no fuel.I want to check the volts at the connection by the fuel tank to see if the pump is getting 12 volts.I have a voltmeter but don't know how to test this, I'm pretty dumb on using voltmeters as I haven't used one much.Thanks for any help.

 

[Opera House]

If you pull the pump fuse and put an amp meter in its place you should measure about 4-5 amps. Below 2.5A the engine will not run. I did some tests a while ago and found the pump will run an engine down to about 7V. remember this is a high bypass system with about 80% of the fuel going back to the tank at idle. Continuity is best test for pump since computer only turns power on for 5 seconds till engine starts. Likely fuel pressure is a bad read. I dont trust any reading unless valve is removed.

 

[90ranajo]

Have you checked the Fuel Pump Relay?

 

[reflex26]

Update

Hi, I pulled the connector apart by the fuel tank and I get 12 volts from the shutoff switch at the connector by the tank.Also there is good ground going back to the front at the black ground wire from the fuel pump and the tank has good ground so I guess it's drop the tank time and replace the fuel pump.Thanks so much for your advise.