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View Full Version : Fuel Pump Noise Fluctuating with other electrical



Caleb
03-02-2011, 12:24 AM
I've noticed since installing the Holley Blue Fuel Pump in my '85 firebird, when i turn on my turn signals or turn on my headlights, I noticed the humming sound from the fuel pump lessens or fluctuates with turn signals. Any idea's? I read into it and some people say the ground wires are shit on the pumps. I've tried improving the ground on the pump by splicing in a larger gauge wire with a heavier bolt on solid metal but, to no avail, its still doing the same thing. I've got the pump also hot wired into my fuse box on a hot "turn key on" spot where it kicks on when turn my key to the on position. Do I need to wire it directly to the battery? Idk. I'm not tearing it apart to put in a new ground wire and void the warranty on it. Maybe I have an electrical short somewhere.

On a side note, that shop that checks out electrical for $35-40, isn't it behind the tic tac somewhere? Maybe I should hit them up for the hell of it?

EDIT:

Maybe I need to wire how this guy is doing it:


I have had a blue pump on my car for years. Recently switched to a black pump when the blue finally wore out. Stayed with this design since all the plumbing /brackets /wiring was in place.

You need to use a relay. Running a hot wire all the way from front to back for the fuel pump is not good, amperage draw goes up. Using a relay lets you run just a small wire all the way back. The small wire only throws the internal switch in the relay, so it doesn't have to be large. Get one for about $5 at a parts store. I use the kind like they seel for use with off-road driving lights. 30amp, heavy duty.

Wire it like this:
10ga wire from battery terminal (or better yet the emergency cutoff switch for the battery) to the + terminal on the relay.

Small 16-18 ga wire from the ignition switch wire (or seperate switch) to the switch terminal on the relay.

Orange wire from the blue pump to the load terminal on the relay (good idea to use an inline fuse holder in between here)

Ground terminal on the relay grounded to the same place as the black wire from the pump.

I use crimp on connectors, but also solder them in place and then cover the joint with heat shrink tubing.

Later,

David Cole

slow ride
03-02-2011, 06:43 AM
Use your current power wire to power a relay and power the pump with a line from the battery. This way your current wiring isn't taxing your fuse distribution box and you get full battery/charging voltage to the pump.

AutoMods
03-02-2011, 07:56 AM
also you could leave it alone, as long as your fuel pressure looks good. i think its somewhat common, just can here it more with louder pumps and also the larger pumps dram more amps.