Wiring up electric fuel pump

mbalbritton

mbalbritton

#@$%!
Joined
Mar 22, 2005
Location
Lakeland, FL
I hate electrical and here I am looking at it again.

Been looking around the ole intrawebz for tips, tricks, and such on wiring up a fuel pump. And specifically looking for best option for where to grab power from. Came across many varied ideas and just left me confuzzled.

A good ground being a key feature, some run a dedicated ground back to a good source and not just the frame. Thought being a bad or corroded ground elsewhere on frame.

One guy even spoke about running a relay off the oil sending unit to cut power to pumping the car of loss of oil pressure.

Where would you grab power from?

Are they (me) over thinking it?

Ground it to the frame, check main frame grounds and pick up a fused link to ignition? Do I want the pump to kick on when I crank or at ignition?
 
You want to make sure the pump is running when key is in both start and run, if it's a decent sized pump you'll want a relay, a click clack pump you can just run off the ign switch.
It's also been proven several times that grounding to the frame is a lot better than running a wire all the way back to battery.
 
So… what’s a click clack pump? Guessing that’s nomenclature for a low pressure pump?

Second, I’m going to resort to my statement around “I hate electrical” meaning it pisses me off because it escapes me for some damn reason. Tell me to wire the white to the white, black to black and red to green and I’ll do it it as clean as a professional. Knowing what that white, black or blue wire does…. Ya…. No….

Which of this birds nest of wires is ignition and which is run?
 
I bought an in tank pump from holley and they have a ground to the frame and the battery on their wiring diagram. They also recommend a 12ga wire.
 
So it's a carbed 258? If that's what ya got, no special pump, you just need ~ 10psi. If the pump you have is more PSI than that, make sure to use the fuel filter that has "One in, and 2 out, the 2nd out returns to the tank, to keep you from flooding the engine and in some cased, causes engine damage from the fuel washing down the cylinder walls. As was said, need power in start and run. A ground to the frame is fine... IF.... you take the ground area to bare metal, use some die-electric grease on the connection, and the surface you ground to. I like to use a relay, that way you draw the working power from the battery or another larger source of power, and when keyed ignition throws the relay closed, you'll have plenty of power, no matter the source closing the relay(doesn't take a lot of power to close the relay. ) I'd make sure to put a fuse in the wire from the battery. And also in the wire sending power to the pump. Maybe a little over kill, but much safer.
 
So looking at the under dash fues box you will see the ACC fuse (20 amp) to the right of it should be a spot for a spade connector. I believe this to be "switched" power meaning key on its hot key off it's not. I would use that to a relay under the hood and then back to the pump. The ground is good to go on the frame (mine is that way and my old K5 was like that factory.
 
Monkeynono said:
So looking at the under dash fues box you will see the ACC fuse (20 amp) to the right of it should be a spot for a spade connector. I believe this to be "switched" power meaning key on its hot key off it's not. I would use that to a relay under the hood and then back to the pump. The ground is good to go on the frame (mine is that way and my old K5 was like that factory.
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This right here. Now you're speaking my language. Thanks!
 
So, got the wiring harness today. Looking at the wires for the pump and harness, WTF is the deal with 10ga. Wires on the harness and 16 or 18 ga. On the pump? Connect a 10 ga. Positive wire to an 18 ga.?
 
mbalbritton said:
So, got the wiring harness today. Looking at the wires for the pump and harness, WTF is the deal with 10ga. Wires on the harness and 16 or 18 ga. On the pump? Connect a 10 ga. Positive wire to an 18 ga.?
Click to expand...
Yes.
Wire gauge is a function of the length.
You can drop gauge on really short runs no problem.
And IDK what fuel pump you’re using but it’s unlikely you’re needing 10ga for it. So no matter what it’s overkill. You’ll be fine.
 
Bebop said:
Yes.
Wire gauge is a function of the length.
You can drop gauge on really short runs no problem.
And IDK what fuel pump you’re using but it’s unlikely you’re needing 10ga for it. So no matter what it’s overkill. You’ll be fine.
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This, I always upsize if it's in question
 
Monkeynono said:
This, I always upsize if it's in question
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And then you end up with a giant overkill wire for no reason.
It's like putting tons under a jeep on 35s. Sure, it'll hold but there are cleaner, better and less expensive ways to get there.

Just learn how to size a wire and you'll be fine. It's not rocket science.
 
I need to do this to the 84 Ford. Do you keep the mechanical pump and have this feed it?
 
ghost said:
I need to do this to the 84 Ford. Do you keep the mechanical pump and have this feed it?
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nope. I took a scrap of 1/8" plate and traced the mech fuel pump gasket on it. Cut it out and bolted it in place of the mech pump. Then re routed the fuel lines coming off the frame in the engine bay to a fuel filter and then the carb and return line.
 
Bebop said:
And then you end up with a giant overkill wire for no reason.
It's like putting tons under a jeep on 35s. Sure, it'll hold but there are cleaner, better and less expensive ways to get there.

Just learn how to size a wire and you'll be fine. It's not rocket science.
Click to expand...
It's just a hold over from doing car audio.
 
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