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Electrical problem no power anywhere

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  • Electrical problem no power anywhere

    Ive rebuild most of my s14 over the last number of years and will hopefully soon be finished but i have ran into an electrical problem and im an idiot when it comes to auto electrics and no idea how to read wiring diagrams

    atm the ecu loom is connected up and the loom to the fuse box is connected bar the section that runs along the front of the car to the lights etc. I connected up a charged battery to confirm everything was working and to get some lights on the dash for the first time in years but cannot get it to work. I first assumed it must be a grounding issue anf found a few small grounds that were not connected and connected them to the nearest bolt for now. Any of the grounds front the loom along the front of the car were grounded directly to the battery neg terminbal as that part of the loom was just sitting loose. the alternator bracket is off being powder coated so i connected up the alternator and ran a heavy cable from the housing to the engine block in lieu of the housing being bolted straight to the block. I have used an alternator and checked continuity for all the earths and they are all good. the big earth that goes to the fuse box only connects with the ignition turned on all the rest seem to be permanent. When checking voltage Im getting slightly over 12v across the battery terminals and the same checking the positive against any earth.

    with all that it still doesnt work. when i connect the terminals im not getting that tiny spark you would normally expect and no sign of power to anything else.

    can anyone help

  • #2
    Troubleshooting an electrical problem on our end is difficult. You really need to learn how to read a wiring diagram and use a multi-meter to see if you have continuity/voltage where you need it.

    Start from the battery and work your way down the line of power distribution. Check to see that no fusible links (the large ~80A) and fuses are fried in the main power distribution box. If a fusible link is burnt, you may have a major short somewhere. Make sure the starter and alternator cables are where they need to be.

    The wiring diagram will also show you which pin to check on the ECU harness for 12V. Again, you should make an attempt to familiarize yourself with them.
    Core4 Motorsports
    CLICK HERE for Wilwood FSL6R Radial Bracket & Rear Wilwood BBK GROUP BUY
    S14 VQ AER Endurance Racing Team


    • #3
      check you grounds. should be one wire from the battery terminal to the chassis and to intake manifold. the other is on the engine harness that connects to the exhaust side of the cylinder head.

      check your power cable. should be 2 wires (on s13 atleast, not sure how many on the s14) going to your battery terminal and a fat one going to the starter from the battery terminal (this one will not stop your instrument lights from lighting up)

      check all your engine bay fuses.

      if all of that is fine then the next step is to start looking at the wiring diagram to verify your relays are fine.