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  • MarkyR
    MarkyR

    Fuel Pump Confusion

    Hello!  I'm a first time car restorer (late 1977 280z), and struggling mightily with the wiring of the fuel pump.  I have put a lot of research into this, and attempted to recreate wiring diagrams, but it doesn't seem to be working for me.  To my (limited) understanding, the fuel pump has to be integrated into a circuit with the oil pressure switch, air flow regulator, and some combination of the EFI, Fuel pump relay, or Fuel pump control relay.  I started doing research into the different pins, and had found that pin 87 powers the fuel pump, so i rigged a wire into that, and connected it to the positive terminal of the pump, and grounded the negative.  upon cranking the engine, i noted that the fuel pump was not turning or taking in fuel.  If anyone knows a way to "jump" the pump to get it to run, or how to actually wire the fuel pump, it would be greatly appreciated!! I'm so eager to see this thing run, and all I need is fuel delivery!

    P.S. I have gotten the fuel pump to turn using 9v batteries, so I know that it works, and is not the problem.  

    I included a picture of my probably horribly wrong rigged up fuel pump.spacer.png

    Greatly appreciate any help!  Thanks!

     


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    First, your picture didn't show up.

    Second, the 280Z did not always use the oil pressure switch in the fuel injection. That only happened in the 78 model year. If you have the oil pressure sender that came with the car, look at the connector. If it is a bullet connector, it is a 77.

    77 and earlier Oil Pressure Sender.jpg

    If there is a T shaped connector it is a 78. 

    78 Oil Pressure Sender.jpg

    It looks like the 78 model year cars started around August 77. What is the build date on the door jamb plate?

    Once you can tell us which model year you have, then we can start to help you.

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    Hello,

    Apologies for the picture not showing up.

    I  had confused the oil pressure switch with the oil pressure sender, the pictures you had attached is what I was referring to.

    The door jamb plate says that the production month and year was 8/77, and upon further inspection my oil pressure sender has the T shape connection (I'll try and link that image).

    Thank you for your response!

     

    oil.jpg

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    Thank you so much, your explanation of the different colored wires and what they do is very helpful, and makes sense.  I will reattempt to wire the pump the right way and repost any problems I may run into in this thread.  

    As a side note, I have read about a way to hard wire the fuel pump to the battery to get it to run? Is there anything you could explain about that?

    Again, thank you so much.  Very helpful.  

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    8 hours ago, MarkyR said:

    As a side note, I have read about a way to hard wire the fuel pump to the battery to get it to run? Is there anything you could explain about that?

    You would have to provide a link. I don't like going straight to the battery for power without fusing. Without a fuse, a short circuit could cause a fire in your car.

    By placing a jumper between the two green/blue wires at the fuel pump relay, you at least have the fusible link to provide some protection.

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    Right, I was thinking that I would need some type of resistance to not burn something out.  

    So to my understanding, if I connect the green/blue wire to the fuel pump from the fuel pump relay, and place a jumper between the two green/blue wires as well, the fuel pump should run?

    Thanks!

    Edit: got the fuel pump to run hardwired to the battery, and had engine cranking and fuel going through it but it still didn't run.  Now going to check if I have a spark and if my injectors are firing correctly. 

    Edited by MarkyR
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    Use starting fluid. If it fires, you know you have spark. If it dies immediately, you probably aren't getting the injectors to fire.

    Don't be afraid to check for corrosion at the ECU.

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    Ah, I was actually using starting fluid while cranking it, and it didn't fire, and never ran; so I assumed there was an issue with the spark.  Guess this confirms my suspicions.  That or I have many more problems to find lol.  But for now, at least I have fuel running through my system.

    ECU looks to be fairly clean.

    Thanks!

    Edited by MarkyR
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