Fuel Pump Wiring Tips

[ForeverDriven]

Hello again,

I'm sure a few of you are used to my username by now, but I've got yet another question. I've had fuel issues for a while now and I've just found out that there are less than 10 amps of current making it to my 340 LPH pump. I assume this is from my control pack's 10 gauge fuel wire going to the factory, what, 16 gauge wire? through two of those disconnectable spade connectors at different points.

For those of you who did high flow pumps, what are your tips? I want to keep my inertia switch in the circuit but I don't need to. Did you just buy a wiring kit? Exactly what things are important to getting 13-14ish amps to the pump?

Any help is appreciated. Thanks!

 

[ttocs]

how did you measure the current? Which pump do you have?

 

[ForeverDriven]

how did you measure the current? Which pump do you have?

Well I put an inline 10 AMP fuse in between the second set of spade connectors near the trunk grommet, ran the car for a few and the fuse never blew. So thats how I figured out the pump isn't getting enough juice

Its an Aeromotive 340 Stealth pump otherwise

 

[ttocs]

so this was at idle? Draw is minimal then but either way it is better to run a thicker wire to it but it may or may not be necessary as some of the higher flowing pumps still do not draw that much current. If you want to use the stock inertia switch then that will be your limiting point in the circuit since it has 16 awg wire in/out of it. But then you might also want to check what the current output is on that system you have to decide if you will need a relay or not.

 

[Adfalenski]

Run a larger wire through a relay from the battery to the fuel pump. Use the old fuel pump power wire to control the relay. That will leave all other parts of the fuel pump system like normal be sure to put a fuse on the new power wire.

 

[ttocs]

for some reason I didn't think about the fact the inertia switch could be used to interrupt the relay supplying power to it and not limit current at all. The stock switch could still be used.

 

[ForeverDriven]

so this was at idle? Draw is minimal then but either way it is better to run a thicker wire to it but it may or may not be necessary as some of the higher flowing pumps still do not draw that much current. If you want to use the stock inertia switch then that will be your limiting point in the circuit since it has 16 awg wire in/out of it. But then you might also want to check what the current output is on that system you have to decide if you will need a relay or not.

I see what you're saying but with these return style systems I thought the pump was running 100% all the time, didn't think putting it under load would be necessary to see accurate draw

 

[ForeverDriven]

Run a larger wire through a relay from the battery to the fuel pump. Use the old fuel pump power wire to control the relay. That will leave all other parts of the fuel pump system like normal be sure to put a fuse on the new power wire.

For sure. Do you know if it is better to solder or use connectors (does either choice reduce current more than the other?)? Also, what should I do about the wiring at the fuel pump plug, is that wire already thick enough or have you had to replace it before?

 

[ttocs]

the system needs to keep the fuel pressure at as steady of a pressure as it can, but as the rpms increase fuel flow increases to supply the additional fuel needed.

As for solding/crimp connectors that is a bit of can of worms among wiring experts. I have been reading from more and more people that I respect the opinion of that proper crimp connectors are better than soldering. The reason they say this is because when you solder there is a spot on the wire where it goes from solid/soldered to movable loose wire and if there are vibrations that allow the wire to shake even a little after time it will break at that point. If the correct crimp connectors are used current is not limited and the wire is less prone to breaking. Now the correct crimp will be waterproof if its exposed to the exterior and big enough to support the current draw that is needed.

 

[ForeverDriven]

the system needs to keep the fuel pressure at as steady of a pressure as it can, but as the rpms increase fuel flow increases to supply the additional fuel needed.

As for solding/crimp connectors that is a bit of can of worms among wiring experts. I have been reading from more and more people that I respect the opinion of that proper crimp connectors are better than soldering. The reason they say this is because when you solder there is a spot on the wire where it goes from solid/soldered to movable loose wire and if there are vibrations that allow the wire to shake even a little after time it will break at that point. If the correct crimp connectors are used current is not limited and the wire is less prone to breaking. Now the correct crimp will be waterproof if its exposed to the exterior and big enough to support the current draw that is needed.

I really think you're thinking of returnless fuel systems and not return style. In return style the regulator simply sends back excess fuel while the pump is at full power all the time. Returnless style is where the computer modulates pump power to meet fuel needs because obviously there is no line back to the tank. I'm pretty positive I wouldn't have load problems with a return style because of this. The pump still takes a full 14 volts at idle like I would assume from how a return style works.

But on the other hand I appreciate the opinion on crimp connectors. I understand these systems pretty well but in terms of power/current delivery through wires I'm still learning. I'm gonna get to putting in larger wire this week.