Electric Fuel Pump Install

[CDL1542]

Hi, 11/70 Z converting from a mechanical to a electric fuel pump for my stroker with triple carbs. I have a couple questions on the wiring that I was looking to get some help with. I've consulted various different builds, threads and diagrams and am planning on wiring in a Holley Red Electric fuel pump. I have grounded the wire and the positive side will be going to a relay (which I have figured out already). My questions are firstly: Should I want the fuel pump to turn on when the key is in the ON position or the START position (Will it still be on if in the start position)? My second question is: Of the Wires going to the ignition switch, which one of these would be the correct one for the ON or START position respectively. I have looked at a handful of wiring diagrams and none of them specify which wire is which. Thank you!

 

Chris

[CDL1542]

Did it the old fashioned way with a multimeter and wound up with a choice of either the black/white OR green wire so I went with the thicker of the two and hooked it up to my relay. Fuel pump works fantastically. My only complaint is that it's a bit loud...

[CDL1542]

For future use. If anyone is attempting to replicate this, I drew up a diagram to clarify some things not mentioned in other posts and attached it for your convenience.

[Jarvo2]

Here's the approach that I took with my '72 240z.

[Chickenman]

Edit: I missed seeing the Inertia switch in Jarvo2's wiring diagram. Always a very good idea.

Another good idea when wiring in  an electric fuel pump for carburated cars is to incorporate a " Crash switch " that cuts off power to the electric fuel pump in the event of an accident. Ford makes a Fuel Cut Off switch that is cheap and can be bought new ( Ford, Napa, Autozone, Summit Racing )  or found in about any wrecking yard. Simple Inertia switch that could save your life. Raw fuel being pumped unto Red Hot exhaust with an unconscious driver is not a good scenario...

 

Edited February 6, 2016 by Chickenman

[cssulliv]

Question - I just wired mine up the way Jarvo2 describes and the pump runs all the time, even with the car shut off. Wondering why this might be the case, or which wires need to be switched around.  Thanks in advance. The diagram has been a great help.

[Zed Head]

33 minutes ago, cssulliv said:

Question - I just wired mine 

Your 240Z?  Where did you get an oil pressure switch?

[cssulliv]

Yes, it was my 240z.  Same one Jarvo2 is using. Saw it on another thread, I believe.  Anyway, I figured it out. I had both the 30 relay and the S terminal on the oil pressure switch both going to the top terminal on the solenoid. I didn't realize there were two terminals. 30 should go to the top and the S terminal should go the lower terminal. Corrected that mistake and it appears to be working as it should.

[w3wilkes]

I wasn't sure from your description... Are you using the original wiring that Datsun put in for an electric pump? That's what I used on my 12/70 built car. The pump comes on when the key is in the run and start positions, but not in ACC.