73 412 Type 4- Fuel injection problem

[raygreenwood]

Stop!.....do not start adding wires. Do not change anything! You have no idea if there is anything wrong yet.
Unless you added something new......there is nothing wrong with your fuel pump fuse in the fuse block.

If the fuel pump relay under the dash "clicks" when you turn on the key....then your fuel pump has power.

There is a single "+" wire coming from the fuel pump relay under the dash....that goes straight to the pump. The other wire to the pump is "-" and goes straight to ground.

So if your fuel pump relay clicks.....and your pump does not run.....it's because either the "+" wire between the relay and phmp is broken or not connected.....or the negative wire plugged into the pump is broken somewhere in the harness.

How did you hook up the new fuel pump?
Ray

[Najemnikarmy]

I put the negative wire on the negative port to the fuel pump and the positive wire to the positive port on the fuel pump. I followed the directions from the fuel pump manual.

[raygreenwood]

[Najemnikarmy]

Okay I’ll try that either today or tommorrow. I didn’t add any wires to the car. I just put a small cable on the battery at one end and put the other end of the wire to the positive side of the connector on the fuel pump just to see if it pumps the gas which lead me to 5 leaks in the fuel hoses so I pretty much replaced every fuel hose under car.

[Najemnikarmy]

So #9 and #7 fuse is getting power but when I texted the positive and negative wire down at the fuel pump I got 0 power for both. I tested al the wires behind it and they all light up as well.

This is my current setup

I found these wires but I’m 90 percent sure there from the radio under the backseat

I thought fuse 7 is for fuel pump.

[raygreenwood]

No......those are factory connectors and there is no "radio" under the back seat.

There are no extraneous wires in this car. Well....actually one....that went to the battery electrolyte tester.

Fuse #9.....does not go to the fuel pump. It goes to the fuel pump relay.

So with the ignition on to position 1....check terminal 30/51 on the fuel pump relay to see if it has power. If so.....the problem may be inside the relay.

The power to "switch" the relay on...to "operate it".... comes from one source ( its transfered by the ignition switch) and the power the relay...."relays" or supplies to the pump...comes from fuse #9.....actually....the wiring diagram says fuse #7.....so trace it from the relay to be sure.

If its hooked up right.....the relay gets power from the fuse block at terminal 30/51.....constantly....even if the key is off. Its only when the key is on....that the relay gets power to make it CLICK to transfer power from terminal 30/51 to terminal 87....which goes to the fuel pump.
Ray

[raygreenwood]

Where are those wires you have in your hand in the picture?

The red one looks like the power feed that goes to your EFI relay under the right hand rear arm rest. The brown one looks like the ground wire to terminal 8 or 17 of the diagnoatic test network....and the yellowish one looks like test terminal 7 that used to check battery electrolyte level.

Check that red wire with a volt meterto see if it leads to terminal 30/51 on the relay under your right rear armrest.

If thats where it goes...thats why you cant start. Ray

[Najemnikarmy]

The red line is a trace of the bundle of wires. The tubing leads up into the backseat area and it’s covered by carpet. It seems like it is leading sort of into the direction of the backseat arm rest relay.

Would that be the reason my fuel pump connections for the positive and negative aren’t getting any power from the wires? I’m going to try and trace them tomorrow and see if there disconnected or broken.

[raygreenwood]

Yes. I am going off memory here....so I cant remember the exact order of events.. I will try to post the wiring diagram in the morning. But.....the fuel pump relay and the fuel injection ecu....that thing under the armrest.....are connected together by a black and yellow wire going between terminal #87 on both relays.

The fuel injection power relay should have a wire going straight to the poistive terminal at the battery. So if the rear relay is missing power the fuel system is miasing power. Ray

[Najemnikarmy]

[Najemnikarmy]

Connected the red wire to the positive terminal and nothing happened than how it was before.

[raygreenwood]

[Najemnikarmy]

Ok. Manual came in today, I’m gonna see if I can find anything about it