Aftermarket EFI and wiring questions Options

[jmargush]

I am in the process of installing CB Performances EFI system.

I have a few questions in regard finding wires from the front of the car to the engine bay.

Fuel pump - Do the two wires that connect to the pump up under the fuel tank, run back to the engine compartment? I need to find a place to tie in the wires form CB's harness instead of running new wires all the way to the front.

Tachometer - Is there a wire that goes to the tach that I can connect to their drop for the tach?

Ignition - There is a drop labeled ignition is there a wire already back in the engine bay or do I need to run this up to the ignition switch?

[Root_Werks]

Depending on the year of your 914, there should be a wire than runs from the relay panel to the fuel pump if it was located in the front trunk (75' and up I think?)

Get a Haynes manual or similar, knowing the colors of the wires helps a lot. Then test to ensure you have the correct wire.

[worn]

I am in the process of installing CB Performances EFI system.

I have a few questions in regard finding wires from the front of the car to the engine bay.

Fuel pump - Do the two wires that connect to the pump up under the fuel tank, run back to the engine compartment? I need to find a place to tie in the wires form CB's harness instead of running new wires all the way to the front.

Tachometer - Is there a wire that goes to the tach that I can connect to their drop for the tach?

Ignition - There is a drop labeled ignition is there a wire already back in the engine bay or do I need to run this up to the ignition switch?

The tach is black with a purple stripe. Found at the distributor and at the rear fuse panel harness connector. The early cars ran the wire for the fuel pump into the right side of the engine compartment.

[GregAmy]

https://tgadrivel.blogspot.com/2020/03/on-m...914-part-1.html

Yeah, it's long. But the wiring answers are in there (including wiring diagrams)...

[bkrantz]

I ran new power and ground wires to the front when I rebuilt my wiring harness (out of the car).

I also used the stock relay board to connect the new EFI wires to the stock system, and created a new cushion wire harness that uses the stock 12-pin plug. That connects to the fuel pump power, ignition, and tach.

BTW, the Dubshop EFI kit includes a tach signal modifier box.

[JamesM]

Fuel pump - Do the two wires that connect to the pump up under the fuel tank, run back to the engine compartment? I need to find a place to tie in the wires form CB's harness instead of running new wires all the way to the front.

Yes the 12v wire to the pump runs back to the stock relay board in the engine compartment. This relay is normally activated by the stock ECU grounding the appropriate pin on that 4 pin connector at the driver side rear of the board. Not sure how the CB system is wired but on my Megasquirt builds I just connect the fuel pump control wire to this pin and use the stock relays and wiring for the pump.

Tachometer - Is there a wire that goes to the tach that I can connect to their drop for the tach?

Yes, tach signal wire comes off the ignition coil. If the signal from the CB system is low voltage you will either need a tach signal adaptor or a small modification to the tach itself for it to work.

Ignition - There is a drop labeled ignition is there a wire already back in the engine bay or do I need to run this up to the ignition switch?

Yes, (assuming its just looking for a 12v ignition on source) again off that 4 pin corrector on the relay board that powers the stock ECU.

Everything you should need is already in the engine bay.

[jmargush]

Thanks so much guys this gets me goin in the right direction.