Cool bean

I'm ditching the mechanical fuel pump for an electrical on and am adding return style regulator. Here's what the wiring will include: power source/10awg wire, circuit breaker, inertia switch from ford Taurus, relay. The relay, inertia switch, circuit breaker will be mounted in jack storage compartment behind passenger seat in my 74 coupe.
My two questions are

1. For the power supply: does it matter if I run a 10 awg from a fused subpanel in my engine compartment OR is it a best practice to supply power from battery (fused of course) due to short length and related voltage drop?
2. What should I use for an ignition positive trugger wire for the relay? Is there a wire under dash I can tap into or do i need to plug into ign terminal of stock fuse panel?

Thanks.

Richard454

For the power supply: does it matter if I run a 10 awg from a fused subpanel in my engine compartment OR is it a best practice to supply power from battery (fused of course) due to short length and related voltage drop?

Go right to the battery- makes no sense to run a large gauge wire all around the car. The jack compartment is a great place for the Ford inertia switch and relay/fuse- that's how I did it. I also wired mine w/ the fuses that light when it is blown- and wired the normally open side of the Ford switch switch to a blown fuse. That way, just by looking at the fuse- I'll know if the switch is tripped or if the fuse is blown for the pump.


inertia switch not tripped-

DSCN5036

Tripped- fuse lights up
and just because in the picture I have used a wire nut - Doesn't mean that's how I wired it AFTER I tested the system...just sayin...

DSCN5038


What should I use for an ignition positive trigger wire for the relay? Is there a wire under dash I can tap into or do i need to plug into ign terminal of stock fuse panel?

Even though you have a fuel shut off for impact and rollover- there are times when you could accidentally run the pump (if going w carb) have a float stuck open and set the car up for a fire....

I'm running an ECU and fuel injection- that primes the pump- then does not turn the pump on again till it sees the engine turning over a settable RPM ( in my case about 500RPM-about twice the engines cranking speed)


In your case w/o a controller- and just being me- I'd wire it so turning on the ignition AND touching the brake petal or clutch would engage the fuel pump- by using a latching relay or a TR7 module.
That way you have less of a possibility of setting the car on fire or filling the engine w/ gasoline.

I'll be glad to draw up a wire diagram for you if you want.

Richard

Cool bean

Thank you; I'm clear on the power supply. I used marine terminals on the new 2/0 battery cable so jumping from passenger side compartment to battery box won't be an issue. I like the light-when-blown fuses, thats what i have for radiator fans, headlights/relay, vac pump, stage solenoid in engine subpanel. I'll get an inline fuse or maybe a smaller panel for pump.

On the topic of a fuel pump shutoff: the car was originally an L48 / automatic trans. I put in a motor ('still have the orig L48, thats a topic for another post.) and moved the oil pressure sending unit to the top port of block because side port above filter was plugged. I could plumb a "T" into the1/4" brass tube for the sendingunit and add a fuel pump switch along with an override switch in the dash. It would be easiest to do that now while interior is out. If i abandon the oil pressure safety switch, my fallback plan is an override switch in the dash.

i'm guessing tapping into fuse box "ign" is the way to go for positve trigger wire for relay.

I'd like to set it up so fuel pump still primes, but stops until oil pressure switch "allows" it to run continuously. So yes, i'd like to take you up on your offer of a schematic. Thank you, Richard!

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