Fuel pump question

[Dan Robertson]

I have a 63 GMC 4000 series truck with a 351c engine. I suspect that I may have fuel pump problems. (It has been in the 20-30 below range for the last week so it could also be frozen but I'm not going to do anything more with it until the weather warms up) I'm not getting any fuel at all at the carburetor. If it turns out that it needs a pump, I believe that I will be converting it to an in line universal electric pump and just plug off the lines and leave the old one in place. My question is how critical is the pressure? I have a PDF repair manual that lists the factory pump at 4-6 psi. Would it hurt anything if the electric pump had a range of 5-7 psi?

[FetchMeAPepsi]

Have you checked the fuel filters? I dont knowif they have 2 in 4000 series but they do in pickups. One after the pump and one before. If youre sure its not the filters you can take off the fuel pump and stick the bottom half of it in a bucket of water then work the pump to see if it's putting out. Dont let it squirt you in the eye though, that first pump is GAS!

[Funky61]

Hello Dan, Some carbs are sensitive to fuel pressure. I had a Holley like that and I've read that certain Edelbrocks are as well.

[Funky61]

Here is an archived post about the conversion.

December 10th, 2011, 07:50 PM
Guest Posts: n/a

Default Re: [6066 GMC] Electric Fuel Pump Converstion ??

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Good idea! I've had manual pump failures as have many on the site. I've made this change using the Carter P4070 electric pump for 2 purposes: as a booster pump (initial start and when switching tanks) plus as a backup if I have a manual pump failure. Some have converted over to electric only putting a blank plate over the fuel pump mounting hole. An electric pump certainly improves reliability. It is simple to install. There is a lot of info on the site. Numerous recommendations, For example: Reference post 31852 ( Lewis Matlin), 4/19/07: " it is simple to install an electric fuel pump on your truck. You need a Carter P4070 pump, some 14 ga. wire, and a fuel pump safety switch. Run the power wire from a run circuit on the ignition switch, through the safety switch, then to the pump. The safety switch must be installed on the oil filter housing, so as to read line pressure. Install a 1/8th NPT run tee in the housing where the low-oil pressure switch is installed, so that both the safety switch and the low-pressure switch operate."
Carter P4070 Electric Fuel Pump and Mr. Gasket 7872 Safety Switch is available from Amazon.com or JEGs.com.
A fuel filter should be installed between the tank and the pump.
Claude O'Tyson- Meridian, Idaho

[Rockdriller]

Run some " Heet " through it....(Fuel additive) after you change out the filters and you may solve your problems.
I have an electric pump and a mechanical one in my 351C that's in my 66 4000.
It sure works nice.