On third fuel pump now...can't be that many bad pumps!... Info..pro systems 440 gph pump. Bypass regulator...alky fuel. Car wasn't running right. Could only get 6 lbs press at track no matter where you put regulator...figured pump was bad. Put on new pump and regulator from pro systems. Then only could get 3 lbs. put old pump back on and had 6 lbs. defective pump?.. Patrick at pro systems agreed. Sent me another pump. New pump came today...can get barely 6 lbs now. Cleaned tank, blew out lines, switched return line,made it supply line, bypass into fuel jug, same results. No matter where I adjust regulator can get no higher than 6 lbs. tried a different gauge also. 12.5 volts at the pump...help!

Liquid filled or dry fuel pressure gauge?

No filter? All tests using the same regulator? Tested the output directly from the pump outlet? Take care. Tom Worthington

Liquid filled gauge. If it was bad gauge I should be able to put pressure high enough to push past needle and seat?... New and old regulator tried.

No filter in system.

The gauge is your problem. Throw it in the weeds and replace it with a dry gauge.

can you connect the fuel pressure gauge to the output of the pump?

quote:

Originally posted by 1320racer:
The gauge is your problem. Throw it in the weeds and replace it with a dry gauge.

This!!!

If it was the gauge that was off...wouldn't I be able to turn pressure up to push past the needle and seat?

Sounds to me like regulator, do you have another you can swap it out with and try?

quote:

Originally posted by jay giles:
If it was the gauge that was off...wouldn't I be able to turn pressure up to push past the needle and seat?

No.

pump pressure, float setting and needle and seat all are part of the equation.

Bottom line is your gauge is a problem. May not be the only problem but must be replaced.

Have 2 regulators....original one a new one.

Change the gauge!!!

could the inlet be constricted somehow ?colapsed hose ,something in tank ect

quote:

Originally posted by rusty:
could the inlet be constricted somehow ?colapsed hose ,something in tank ect

This was also my first thought, collapsed hose on the inlet or maybe just a flap inside the hose.

Inlet line is a #10 line. It's only a foot long. I've checked it and it's ok,checked the tank also. No one in this small hick town has a gauge...lol

Summit/Jegs overnight.

Two things I have not seen mentioned yet.

What is the fuel pressure at the outlet of the pump and/or at the input to the regulator?

Have you done a flow test into a gallon can to verify the system can flow what it should?

3 pumps no.There is some form of restriction. Flow test into a container. Any foam in the tank?

3 pumps same liquid filled gauge that shows different fuel pressure based on the temp/viscosity of the glycerin in the gauge. If you can’t get a dry gauge then drain the liquid out of yours.

quote:

Originally posted by Joe Burkleo:
Have you done a flow test into a gallon can to verify the system can flow what it should?

A meaningless test created nearly 40 years ago to sell fuel pumps.

This message has been edited. Last edited by: 1320racer, July 18, 2020 02:17 PM