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Just Bought a '84 Z31, Fuel pressure regulator bad?

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  • Just Bought a '84 Z31, Fuel pressure regulator bad?

    Hey guys, this is my first post to the forum. I got a Z31 (NA) off of craigslist and it has several problems.
    First, it will start and run off of starting fluid. That clearly says that little or no fuel is being injected into the motor.
    I took the bottom hose off of the regulator to see if it was just sending it all back to the tank when I turn the key and sure enough it was.
    None is coming through the vacuum line on top as some do when the diaphragm ruptures.
    The fuel pump is always making noise, it never builds pressure and stops.
    Does this mean that it is broken or is it normal for it to do this?
    (also, the digital dash, radio, and pop up headlight motors aren't working and resoldering the PCU did nothing)

  • #2
    Also, it is NA


    • #3
      do you have/can you borrow or rent a fuel pressure gauge? I would buy a new FPR and replace the fuel filter while you've got the hoses popped, it's 60 bucks in parts for both but then you can test the fuel pressure and if you don't get 37PSI at the rails when cranking, you know you're dealing with an issue at the fuel pump. Resist the temptation to slap in a cheap adjustable FPR while you're still trying to get the car running.

      for the other stuff, this sounds like a silly thing to check but are the appropriate harnesses plugged in inside the dash? that's all stuff that wouldn't be working if someone pulled the dash and then just slapped it back in since they couldn't get the car to start anyway.


      • #4
        Thank you for the response FrozenZ. But I have realized, this forum sucks. I've never had to wait for longer than an hour for a reply (unless i posted late at night).
        Within the time frame of me starting this thread and getting my first reply, I pulled PCU for the dash, resoldered it, re installed it, put in a new FPR, removed and disassembled the ECU, found some fried components, went to a pull-a-part in another state, pulled an ECU, realized it was from the wrong year so I didn't buy it, found one online for $30 and ordered it, stripped and repainted the plenum cover, cleaned the engine bay, installed a new steering wheel, cleaned every square inch of glass on the car, pulled the stock radio and figured out why it wasn't working.
        I'm never posting on this forum again.


        • Bates Z31
          Bates Z31 commented
          Editing a comment
          You are posting regarding help for a Z31. The bastard Z of the Z family. There aren’t many of us enthusiasts left. And when you act like an ass, like you currently are, you will certainly not receive help the next time you are in a bind. Also, forums have been dead for years thanks to FB. You want help 15 seconds after posting? Go buy a S13 then and let a bunch of know it all kids flame you.

          Personally, with your attitude, I doubt anyone would want to help you.

      • #5
        Dude, if you think there are other forums you can get help your mistaken, these are older cars with a small following. Geez


        • dbruce
          dbruce commented
          Editing a comment
          yeah wow ,,,