What is best way to add an electric fuel pump to early 240z?

[240260280z]

I am considering going electric on the restoration as I will otherwise have to drill out the N47 head to allow the clacker arm to enter the head. (At least the stud holes for mounting the pump are there and they are threaded).

So rather than do this, I am considering the following:

1. Fuel Pump Relay controlled by 12V signal from a pressure switch on the oil sensor

2. Fuse and 12V lead to pump motor via the relay

3. Maybe a cut-off switch to the relay control for security.

Any recommendations?

Is 280zx oil pressure sender/switch same thread as on l24 block?

Edited August 6, 2011 by Blue

[tlorber]

On my '73 I have an electric fuel pump on my car that was on when I got it. I also have an N 47 head and the pump is mounted on the right front fender. It is currently powered off the distributor circuit (vampire tap near the ballast resistor) which I'm not crazy about. I believe there is a circuit near the glove box that is heated up with the ignition switch. I plan on tying into this with a manual kill switch and a relay so that the pump is powered directly off the battery. I've heard that it is better to push the fuel than pull it, and that the pump should be near the gas tank. My car is actually wired for an electric pump, but I have an internally regulated alternator with the zx plug. Rather than risking a conflict I think I'll keep the pump where it is and just reroute the circuitry. Keep in mind that your wiring may differ.

[hogie]

I temporarily used an electric pump on my 72. There is a circuit in the center of the dash that you can fuse to send power to the wires already by the fuel pump. A quick search should be able to point it out for you. I actually ran a ford fuel pump cut-off switch and a relay in line with that instead of an oil pressure switch. I found a threaded hole in the rear cross member that I was able to bolt the pump to.

[SteveJ]

Phil,

Look at the EF section of the 74 FSM, in particular pages EF-7 and EF-8. I think it's a great way of wiring the fuel pump in a car with an externally regulated alternator.

[240260280z]

Thanks Steve! That is good info.

[240ZGL]

My 73 has the electric pump mounting in the rear near the tank and the wiring is also there with the fuel level sender wires. I'm running a Facet low pressure pump, I had to cut the yellow wire going to the relay under the dash on the passenger side and then install a Bosch relay that is tripped from the on wire coming from the ignition switch. Works great, all automatic. And yes you want the pump to push rather than pull. I just got thru pulling the mechanical pump off the engine and blocked off the opening. The mechanical pump was leaking fuel into the block and I was not getting much flow to my triples. I'm now looking to do a dual pump setup in the rear, maybe as a backup in case the main pump were to fail.

[240260280z]

Well I am fond of the clacker as I love mechanical technology but I never liked it when it lost its prime.

I was always thinking that a bulb primer by the tank would have been good addition for emergencies with its one way valve to boot. Hey I guess you now know I used to run outboards in the Canadian back woods .

[SteveJ]

Phil,

While I'm thinking about it, keep in mind that if you put in an internally regulated alternator, this won't work (unless you install a high power diode). A lot of us found this out when we put in internally regulated alternators because the batteries would run down due to the fuel pump relay being constantly energized. I found the connector that was responsible for that and took it out. My battery stopped draining after that.

For anybody who is curious, I recreated the drawing in the FSM since the scanned copy is on the light side.

[240260280z]

For my current plan:

Control:

The signal to energize the relay would come from the ignition circuitry. When the key is off the energy draw from the battery would be off. As well this control signal would also go through the oil pressure switch so even with the key turned to on and the car not running, the pump would not run. The pump would only run when cranking AND oil pressure OR when running AND oil pressure. It may have a switch in series for theft protection.

Power:

The pump would draw from a separate circuit that is fused and is connected as electrically close to the battery send and return as possible. It would also go through the main contactors in the relay.

OR

Drill out a hole in the Maxima N47 head where the fuel pump goes then die grind the triangle.

Edited August 7, 2011 by Blue