How to check fuel pump voltage ?

[rastaz]

Can anyone tell me how to check voltage at the fuel pump? I do have a voltmeter.

 

[Quick6'n'-K.C.]

tan with white strip wire at the quick connect at the rear of the car-
you will see it at neat the driveres side rear bumper area

probe the tan with white with your pos lead
and use the frame as the ground

try it with the car running

post back what you find-- im up for a good laugh to see what they are stock

 

[Steve Wood]

Use the sheet metal as the ground as the frames are not routinely grounded in our car.

 

[rastaz]

Thanks guys,

So what kind of voltage should I be looking for? The pump is hotwired.

 

[scottyb]

Don't know if it is the norm, but mine went from 12.9 to 14.1 when I hotwired it.

 

[Quick6'n'-K.C.]

it should be over 12+ when its hotwired

why would you be checking it by the way?

 

[rastaz]

I'm checking it in relation to my other post in which I was trying to ascertain if my current XP pump is no longer enough to supply my motor. I just wanted to rule out any other problems before I upgraded pumps and found out that it really wasn't the pump.

I would also be interested in opinions if I need to upgrade if I should go to a single walboro 340 or a double pumper. Check my sig for the motor buildup. I think it should run low 11's.

 

[Steve Wood]

The XP should be fine as long as it has not gotten old and weak.

 

[no rice]

My voltage was really low until I hotwired it.

 

[rastaz]

Originally posted by Steve Wood
The XP should be fine as long as it has not gotten old and weak.

Well its an original XP pump which I believe was just a shimmed stocker. It is 6 years old and has 70,000 miles on it so I'm thinking that it is past its prime...

 

[Steve Wood]

Yes, I would think it is due again...Ihad one of the early ones as well...I replaced it a couple of years ago as I recall.

 

[Racetronix]

Originally posted by Quick6'n'-K.C.
...probe the tan with white with your pos lead
and use the frame as the ground

BZZZZZZTTTT!

The voltmeter's ground wire should be placed on the fuel tank's body not the frame of the car. This reading will not be 100% accurate as the pump is not at WOT fuel pressure and the vehicle voltage is not where it would be under WOT either. This test point does not factor in the line drop through the sending unit's harness.

Jack
Racetronix

 

[PaulRV6]

Jack's hot wire kit ground?????

This is a question about the Racetronix hot wire kit, does the ground wire get mounted on the same gas tank strap bolt as the relay gets mounted?
Jack, what level voltage can I expect with your kit. Thanks

paul

 

[Racetronix]

Hi Paul,

All the info you need is at this link:

http://www.racetronix.com/Manuals/RX-G7-FPWH/RX-G7-FPWK.html

The spiked ring terminal goes onto the same tank strap bolt that the relay mounts to as shown in the install procedure.

The metal clip slides onto the edge of the tank.

The voltage at the connectors should be within 2% of the alternators output voltage under normal vehicle operating conditions. This % may increase if your battery's charge is low or many high power accessories are on as the harness can not make up for losses in the vehicles grounding system. This is why it is important to install the body ground upgrade as it helps to minimize this voltage drop.

Jack
Racetronix

 

[PaulRV6]

Jack, what is "The metal clip slides onto the edge of the tank" for?
Does this come in the kit?

When I installed the wire to the front of car, I ran it thru a hole in the bottom of the frame rail and pushed it right up and around the wheel well through the frame well. It came out right at the fuel filter and up to the front. No problem going right thru the frame rail, hidden and out of the way.
Thanks, now that I'm done. Didn't know ya had directions up. Oh well.

paul