Electric Fuel Pumps

2101 Views 15 Replies 9 Participants Last post by alwill923, Nov 25, 2021

Molon Labe

Discussion Starter · Nov 20, 2021

I've had two Carter P4594 electric fuel pumps fail within 300 miles. The first one ran for 50 miles and just quit making any pressure. The second one would run ok then start making a really loud howl - you had to yell over it in the car. What can you guys recommend for a reliable and quiet pump?

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BogiesAnnex1

· #2 · Nov 20, 2021

First off where are you mounting it. Rotary vane pumps need to be mounted low equal to the tank bottom or lower. They do not pull very well so they need essentially to be primed. Most fuel feeds come off the top of the tank. If yours is like this you need to initiate a syphon before connecting the inlet hose to the pump.

Also these pumps work best as close to the tank as you can get them.

Likely if it makes the noise you hear it’s having trouble feeding on the inlet side. Not that pumps don’t fail, but you need to verify if your meeting the requirements in the first paragraph. Carter instructions show several mounting locations at close to more distant from the tank. In the case of these type pumps closer to the tank and low is the better solution.

Bogie

Reactions: 1

Molon Labe

Discussion Starter · #3 · Nov 20, 2021

BogiesAnnex1 said:
First off where are you mounting it. Rotary vane pumps need to be mounted low equal to the tank bottom or lower. They do not pull very well so they need essentially to be primed. Most fuel feeds come off the top of the tank. If yours is like this you need to initiate a syphon before connecting the inlet hose to the pump.

Also these pumps work best as close to the tank as you can get them.

Likely if it makes the noise you hear it’s having trouble feeding on the inlet side. Not that pumps don’t fail, but you need to verify if your meeting the requirements in the first paragraph. Carter instructions show several mounting locations at close to more distant from the tank. In the case of these type pumps closer to the tank and low is the better solution.

Bogie

Pump inlet is slightly above the bottom of the tank. It's rubber mounted about 16" from the tank outlet which is on the bottom. There is a filter between the tank and pump. The pumps that failed are identical. The initial one never made the howling sound and the one that howls made no odd sounds for about 100 miles. Now the howl comes and goes.

ericnova72

· #4 · Nov 20, 2021

what's the line size and micron rating of that filter used before the pump inlet??

Too small and too fine can both be restrictions.

Reactions: 1

Molon Labe

Discussion Starter · #5 · Nov 20, 2021

ericnova72 said:
what's the line size and micron rating of that filter used before the pump inlet??

Too small and too fine can both be restrictions.

5/16" line and 40 micron inlet filter. 10 micron after pump.

ogre

· #6 · Nov 21, 2021

9psi pump, why do you run an electric pump when oem stock pump will work?
unless your motor has the need for electric pump
58 truk has efi and needs 45psi, i run an oem gm in tank pump, available from everywhere in stock for $35

Reactions: 1

ericnova72

· #7 · Nov 21, 2021

Molon Labe said:
5/16" line and 40 micron inlet filter. 10 micron after pump.

Could be a big part of the issue.
5/16" is small for any kind of performance engine, i know GM in the muscle car era anything over 250 HP got a 3/8" line.
As far as filter, 10 micron is for fuel injection after the pump, 40 and 100 micron is a pre-filter on EFI.
For a carb, 100 micron pre-filter, 40 micron after the pump.

Carter pumps were always a go-to for quiet street electric pumps for carb use without breaking the bank, but maybe something has changed in this new "global economy"?? IDK

Mallory Comp pumps are quiet, but also expensive. Same with the Holley HP series pumps, and Weldon's. All these are gerotor design, and not the noisy vane style pumps.
The inline HP pumps are turbine style and also quiet....but also $$$.

Don't even think about the inline "buzzer" plunger/flapper pumps.(Holley Might-Mite and similar)

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Hotrod46

· #8 · Nov 21, 2021

How is the pump mounted? With the motor up or down? Carter pumps have to be mounted motor down. Supposedly they fill with fuel to lubricate and cool the motor kind of like a modern EFI in tank pump. Unless Carter quality had gone away, I have had great luck with them mounted motor down.

jagco

· #9 · Nov 21, 2021

What kinda car this is in, i would run 1 off the motor, Mallory is my pump of choice for electric. 2nd thing i would not run a dead head, run it with a return line. 3/8 lines/6an, I had this for 12 years just rebuild it.

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2old2fast

· #10 · Nov 21, 2021

No one has mentioned adequate electrical supply ..I run 30 amp relay with 10 ga. Wire , same hollley black pump for 18 years , plus or minus 45k miles , deadhead 1/2" line tank to pump to filter ,3\8 line filter to reg to carbs .fram canister pcg 1. Yes , it's a bit noisy but I know its running

Reactions: 1

cerial

· #11 · Nov 21, 2021

My 87 V10 chevy pickup with a stock 5.7 TBI. Has been running a Walbro 225 style inline pump.

These pumps are strong and very reliable while still being affordable.

The 87 has three 3/8" lines at the bottom of a in cab tank that converge into 1 before going through a pre/post filter. Both filters use a steel mesh screen and I run them with 30 or 40 filters. The return line is not filtered and goes to the bottom of the tank (using the old pickup with sock ripped off).

Including the high pressure fuel line and the tank I have under $300 in the entire fuel system. Its overkill for tbi but just right for a LS later.

The 87 v10 is my backup drive it during a ice storm with temps in the -20's truck. I would not trust any other pump except the walbro to keep the wheels moving.

Reactions: 1

Molon Labe

Discussion Starter · #12 · Nov 21, 2021

The line is actually 3/8" and I really don't think my installation has anything to do with the problem. Just looking for recommendations for quiet, reliable pump. Has to feed a 351W making a little over 400 hp that is basically a cruiser and I won't be wringing it out very often - never on the strip

Tire Wheel Automotive tire Vehicle Car

.

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cerial

· #13 · Nov 21, 2021

Your pump is above the bottom of the tank and (it looks like) it needs to pickup the fuel. It may work. but if you can mount it below the tank it might solve your issue.

That rubber your using for isolation also looks a bit on the thin side.

2old2fast

· #14 · Nov 22, 2021

Molon Labe said:
The line is actually 3/8" and I really don't think my installation has anything to do with the problem. Just looking for recommendations for quiet, reliable pump. Has to feed a 351W making a little over 400 hp that is basically a cruiser and I won't be wringing it out very often - never on the strip View attachment 620294
.

That 90° fitting cuts the flow by up to 50%

Reactions: 1

jagco

· #15 · Nov 24, 2021

Just me mind you i would run a Mallory 110 remove that 90 you have and run a more rounded 90 , I have use holley's pumps freaken things loud had few go bad. I do no for me having a return line makes the pumps I used last longer. this setup I have 2 fuel pumps and 2 tanks. I have my return line in the gas filler neck low part. the return line not pushing against gas in the tank. Maybe the carter pumps you have, is weak from the factory. The mallory pumps seem to me last longer. Pics of the pumps and return line.

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alwill923

· #16 · Nov 25, 2021

++ for Walbro

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