1971 porche 1.7, fuel pump ? Options

[milwlandrover]

I was having a bunch of problems with the car. I took it to a shop with 914 experience and he found several of the cylinders were sticking. Someone had installed an EXTRA fuel filter inline, and the wrong plugs. He sorted it out and recommended I replace the fuel lines with something stronger (I already had plans for that but wanted to get it running first.) It ran great for 2 days then it just quit. Felt like a fuel problem. The pump was working but not getting power. With this Corona virus thing I didn't have many options. I found a relay at a shop that was open and replaced the relay but that didn't do the job. I had it towed back to the shop and he is flummoxed. Figures it is a wire to the fuel pump but doesn't have a wire diagram to trace it. Any suggestions and/or a wire diagram. I think I have a diagram for everything EXCEPT the fuel system (part 2 it the PET manual. thanks in advance and stay safe

[JamesM]

I was having a bunch of problems with the car. I took it to a shop with 914 experience and he found several of the cylinders were sticking. Someone had installed an EXTRA fuel filter inline, and the wrong plugs. He sorted it out and recommended I replace the fuel lines with something stronger (I already had plans for that but wanted to get it running first.) It ran great for 2 days then it just quit. Felt like a fuel problem. The pump was working but not getting power. With this Corona virus thing I didn't have many options. I found a relay at a shop that was open and replaced the relay but that didn't do the job. I had it towed back to the shop and he is flummoxed. Figures it is a wire to the fuel pump but doesn't have a wire diagram to trace it. Any suggestions and/or a wire diagram. I think I have a diagram for everything EXCEPT the fuel system (part 2 it the PET manual. thanks in advance and stay safe

Can you hear the relay engaging when you cycle the key to the "on" position?

If the Relay is clicking then the issue is most likely somewhere between the relay itself and the pump (bad relay board connection, wiring, or pump itself)

Wiring from the relay board to the pump come off of the forward most (T14) connector on the relay board, (pin 13, most forward left pin if facing the front of the car) wire in the harness should be black w red stripe, this runs directly to the fuel pump.

The relay itself is controlled by a ground path enabled via the D-jet ECU (most forward left pin on the 4 pin connector to the d-jet harness) To test the pump you can jumper across the fuel pump relay itself, to test the relay you can ground out the activation pin where the d-jet harness plugs in. If grounding from the 4 pin connector activates the pump relay but cycling the ignition key does not, you have a bad ECU or FI harness.

[JamesM]

This might help

[milwlandrover]

I was having a bunch of problems with the car. I took it to a shop with 914 experience and he found several of the cylinders were sticking. Someone had installed an EXTRA fuel filter inline, and the wrong plugs. He sorted it out and recommended I replace the fuel lines with something stronger (I already had plans for that but wanted to get it running first.) It ran great for 2 days then it just quit. Felt like a fuel problem. The pump was working but not getting power. With this Corona virus thing I didn't have many options. I found a relay at a shop that was open and replaced the relay but that didn't do the job. I had it towed back to the shop and he is flummoxed. Figures it is a wire to the fuel pump but doesn't have a wire diagram to trace it. Any suggestions and/or a wire diagram. I think I have a diagram for everything EXCEPT the fuel system (part 2 it the PET manual. thanks in advance and stay safe

Can you hear the relay engaging when you cycle the key to the "on" position?

If the Relay is clicking then the issue is most likely somewhere between the relay itself and the pump (bad relay board connection, wiring, or pump itself)

I can not hear the fuel pump engage when the key is turned on. I definitively could hear it prior to when it killed. I was driving approx. 40mph in 3rd when it killed on the road

Wiring from the relay board to the pump come off of the forward most (T14) connector on the relay board, (pin 13, most forward left pin if facing the front of the car) wire in the harness should be black w red stripe, this runs directly to the fuel pump.

The relay itself is controlled by a ground path enabled via the D-jet ECU (most forward left pin on the 4 pin connector to the d-jet harness) To test the pump you can jumper across the fuel pump relay itself, to test the relay you can ground out the activation pin where the d-jet harness plugs in. If grounding from the 4 pin connector activates the pump relay but cycling the ignition key does not, you have a bad ECU or FI harness.

[davep]

That relay board often fails also, so some circuit checking is necessary.