What is this relay????

  • #1

    What is this relay????

    I took out the dash in my 86 300zx NA-T. And found this relay under the dash. It reseted once i pushed the button down. Im also having all sorts of problems with the ignition system. Im not getting any power to the igniter so theres no spark and the injectors are not pulsating, Although im getting power to them. I already replaced the ecu, fuel pump, engine harness, multiple relays, distributor, spark plugs, coil, and igniter. The car turns over but does not start. I have fuel pressure, so i dont know what the problem is. If somone knows please help.
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  • #2
    Its a hold relay:

    Hold relay (only for Canada analog) type combination meter equipped model
    I have no idea what it is for, but it seems like its for the dash display and likely unrelated to your problem.


    page EL-192 of the FSM located here

    http://xenonzcar.com/z31/FSM/1986/EL.php



    Unfortunately, it sounds like you are dealing with an electrical basket case (the worst kind) and an accurate diagnosis over an internet forum is pretty f'n difficult.

    Get cozy with the electrical system related pages of the FSM and use a test light or multimeter to verify that the harness connections between the ECU and the various components are correct.

    Good Luck, maybe reach out on some Facebook groups to see if there is anyone in your area that has a Z31 and is willing to assist.






    84 AE/Shiro #683/Shiro #820/84 Turbo
    • 1 like
  • #3
    That relay is the hold relay for the "Emissions" light aka the o2 sensor timer light.
    • 1 like
  • #4
    what have you swapped and/or have done so far. if the fuel pump primes when the key is turned on the ecu is powering up. if the ecu has no input from the crank sensor in the distributor it will not attempt to fire the injectors or send a spark.

    the fuel injectors do have power all the time even with the key off. the ecu triggers the ground side switching to fire them.

    have you tried getting the codes from the ecu? if you get a code 11 then chances are you are not getting a engine speed.
    • 1 like

    Comment

    • Julez1787
      #4.1
      Julez1787 commented
      02-26-2019, 09:37 PM
      Thanks for the input. i will check to see if the the connection from the crank sensor is good and is getting power. However, i did change the distributor from my other running 85 turbo and still nothing. I replaced the entire engine harness and that didn't do it either. The ecu isn't giving any codes at the time because the ignition system isn't working. I know the ecu is not the problem because I have 3 different ecu's and all work fine on my other car. The fuel pump went out on me yesterday, so I'm waiting for a new one to come in. Hopefully that relay has something to do with it.
  • #5
    Found my problem! Turns out the 15 amp fuse under the drivers side kick panel had some play in it. And it was causing it to not make good contact.

    Now the ecu works and is giving me codes 13,23,24,31. anyone had a crank but no start issue with these codes?
  • #6
    code 13 is for a cylinder head temperature sensor. if its not working and cold out its almost impossible to start with out it. the ecu goes into a programmed curve mode and assumes the temperature is 68 degrees out.

    code 23,24,31 can be ignored for now as they require input from the user to clear them.

    are you getting spark and injector pulse's?