63 4657 Fuel Pump - Low Pressure

[Harry S.]

Quick one, what would be the symptoms of my fuel pump only having 3.5 pounds of pressure? It's on a 63 with a WCFB.

When starting cold and when hot.

It is not leaking gas.

Thanks

Pressure and hook-up. They are sideways, sorry about that.

[John L.]

[John L.]

[John L.]

[Frank D.]

Re: 63 4657 Fuel Pump - Low Pressure

Don't overthink it - the pump may just be tired...

I have that exact same gauge and they are accurate - attached is the technique for the volume test for the fuel pump BTW...

I have 2 "no frog pad" AC-logo and dated 4657s I rebuilt on the garage shelf and have seen almost all the bad things that can happen with them.

Your pressure is significantly short of what it should be and could be due to many things; a leaky diaphragm, improper assembly after a rebuild or a failing popitt valve. Its time for a rebuild.....

Check your oil for any signs of fuel contamination and even if you remotely suspect this has happened, count on an oil and filter change...

[Harry S.]

Re: 63 4657 Fuel Pump - Low Pressure

Don't overthink it - the pump may just be tired...

I have that exact same gauge and they are accurate - attached is the technique for the volume test for the fuel pump BTW...

I have 2 "no frog pad" AC-logo and dated 4657s I rebuilt on the garage shelf and have seen almost all the bad things that can happen with them.

Your pressure is significantly short of what it should be and could be due to many things; a leaky diaphragm, improper assembly after a rebuild or a failing popitt valve. Its time for a rebuild.....

Check your oil for any signs of fuel contamination and even if you remotely suspect this has happened, count on an oil and filter change...

Thanks Frank.
The gauge is new so I believe the reading is good. I have a pump on the shelf that reads at 5.5 so I'll put that in. First I'm going to install another fuel filter by the tank. While I have the line closed the pump will get changed. No sense taking a gas shower.

I need it to get a bit warmer first.

Cheers

[Dick W.]

Re: 63 4657 Fuel Pump - Low Pressure

Thanks Frank.
The gauge is new so I believe the reading is good. I have a pump on the shelf that reads at 5.5 so I'll put that in. First I'm going to install another fuel filter by the tank. While I have the line closed the pump will get changed. No sense taking a gas shower.

I need it to get a bit warmer first.

Cheers

Filters installed before the pump will lower fuel pressure somewhat

[John D.]

Re: 63 4657 Fuel Pump - Low Pressure

That pump would be perfect for a fuel car. Gail Parsons told me long ago a fuel car only needs a pump putting out 3 to 4-1/2.
My thinking is it could be a tad higher.