LOUD fuel pump....help

[Dubnova]

Hey guys, I have a cpp tank with a new wallbro pump in my 65 C10 ls3 swap and it's LOUD after the pump has been pumping a minute or two. I have swapped out the pump twice and I can't seem to find the problem. Could it be the tank (maybe) mounting or just the factory style pumps? LS3 runs perfect but, the pumps whines like a whipple blower.

[nsb29]

A inline pump is always going to be louder than one in your tank Post a picture of your mounting I put mine in the tank thay run cooler to

[mongocanfly]

my walbro255 is mounted over the tank right behind the driver door...only time I hear it is when the switch is on before cranking...with engine running I have to get really close to the pump to hear it

[BR3W CITY]

Originally Posted by Dubnova

Hey guys, I have a cpp tank with a new wallbro pump in my 65 C10 ls3 swap and it's LOUD after the pump has been pumping a minute or two. I have swapped out the pump twice and I can't seem to find the problem. Could it be the tank (maybe) mounting or just the factory style pumps? LS3 runs perfect but, the pumps whines like a whipple blower.

The higher/farther the pump is from the sump it'll be working harder to draw, which can sometimes cause some noise, but its also worth looking at your lines for any pinch points. What is your filter situation?

[Dubnova]

I forgot to say that its mounted in the tank

[LH Lead-Foot]

My guess is the pump in touching the bottom of the tank. Top referencing fuel sender / pump assemblies hang from the top down and sit off the bottom. A quick measurement will show you the problem. Adjusting the pump slightly higher will fix the problem.

Note: For those with newer vehicles, 94 or newer;
Modular Reservoir Assembly are the newer spring loaded pumps that one has to push down to compress the springs to reference the bottom. This is bottom referencing to the obvious, but because of "Misfire" codes is required. The bucket hold fuel to help cool the pump and lubricate it, but provides an un-aerated supply of fuel to the injectors. This too, wear out a pump quickly.

The problem was so bad that OEM's had misfire codes relaxed by the number or counts of mis-fire needed to turn the CEL on. This was 97. A venturi-valve with second filter was added to correct the problem and keep fuel in a bucket for the pump.

The plastic bucket type (After market w/ metal trays) will have rubber bumpers on the bottom to eliminate tank vibration, making like a loud speakers cone.

If the tank is low or as you go around a corner, gas sloshes off to one side, this causes aerated fuel, volume drops, pressure is reduced, engine goes lean, misfire. Many have a high pressure bleed on top of the pump that feed a venturi oriface that pushes fuel into the bucket again. But in doing so, creates a suction on the bottom to pull fuel in and maintain a level of fuel for cornering.