1975 280 z Fuel Pump has no power

[shadesh]

Thank You for your feedback.

When should the other pins light up.?... upon cranking the engine?

[m4xwellmurd3r]

i'm not too sure, because all the other pins are doing really is picking up the level of resistance created by the movement of the flap.

[zmaster]

I also have a 1975 280z coupe, and I am having the exact same problem as you are with your 280z. The rectangle box under the coil would be called a ballast resistor

1) Do your injectors pulse when you turn the ignition key to the on position, as it would to prime each of the cylnders?

2) Did you check to make sure the EFI fuseable link is in good working order. It is the wire circled in the picture. http://i296.photobucket.com/albums/mm195/hybridzmaster/EFIharness.jpg

3. I was told to read this thing called the EFI Bible, created for the 1975 280z it has everything you need to know about the EFI System. except the amp rating for the EFI harness. It also has the diagnostic tests you can perform on the ecu to see if each part of the efi system is functioning correctly here is the link. READ THIS IT IS VERY IMPORTANT http://www.atlanticz.ca/zclub/techtips/efisystem/280zfuelinjectionbook.pdf

I hope this helps you out. read this memorize this, and print it out if you have to.

[zmaster]

too my knowledge so far that I have learned about the 280z's is that I think after 75 they changed the efi system a little bit.

[shadesh]

I guess when you have an old car, surprises should be expected. I could kick myself just about now. I hope someone will see this post if they are doing what I did.

So... there are two wires at the fuel pump. Per the wiring diagram, one is green and the other one is black. When I looked underneath my car, I saw two wires but one was green and the other was red. .. by the way, this is after I fixed the AFM so that the fuel pump would turn on when I cranked the engine.. . Thanks fellas.

I connected the green wire to the negative (-) side of the pump and the "red" wire to the positive (+) side of the pump and wallah!!, the pump would turn on when I cranked the engine. BUT, there was no fuel flowing out of the pump.

I could not understand why the color of the wiring on the car was different from the wiring diagram. A bulb went on in my brain and I decided to test the wires using a test light. Upon doing so, the green wire lit up and the red wire did not.

Here is the bummer part. The wires at the fuel pump are original. The sleeve on the red wire was originally black. This was the ground wire. Over the years, the black coating wore off to expose the red sleave underneath. So when I was taking the "red" wire, I was actually connecting the ground wire to the + side of the pump and the green to the - side of the pump. This was causing the pump to work but in reverse?

...so the lesson is to use a test light to test the wires before connecting. This was a frustrating experience.. the AFM, the fuel pump, the wiring.... but I want to thank you guys for your input. Now I have a fuel pump that works as it should. Thanks!!!