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  1. #1
    Join Date
    Jul 2017
    Posts
    131

    Strange voltage and no start with new setup. Need HELP

    Update: adding the ground seemed to fix the issue. As for the strange voltage i experienced after adding the ground, my father in-law suggested i put a load on the wire with high voltage using a test light while using the volt meter. If the voltage on the volt meter dropped to O then i was good, if it did not drop we had a bigger issue. He said volt meters act funny sometimes but this will help determine the problem.




    I'm just starting my car for the first time, it has a new AAW harness and a swap harness for a Gen V motor.



    My power setup on the car mimics Mad Electrical's setup with a trunk mounted battery in my 68 camaro and goes as follows:
    0/1 wire from battery to ford solenoid (Allstar Performance with 4 studs total) It connected to the right stud if that matters?
    0/1 wire from the solenoid to the starter. On the left side stud it it matters
    8g wire from the alternator to a terminal block in the engine bay near the booster then goes to the battery for charging.
    AAW harness gets power from the terminal block
    Crank purple wire goes to Lokar neutral safety switch
    Starter purple wires comes form the neutral safety switch to the starter inlet on the swap harness
    18g or 16g (cant remember) goes from the starter side of the neutral safety switch to the Ford solenoid to activate it.

    Simple right? Kind of but I'm getting strange voltage readings and no crank.
    alternator, battery side of solenoid and all accessories get 12v as they should with key on and cranked.
    The S terminal on the solenoid has 0v with key on and 10v while cranked... not 12
    The starter side of the terminal gets 8v with key on and 10v while cranked. should get 0v with key on.
    The 4th terminal has around 20v with key on and off. Not using this one but worth noting
    All purple wires are at 0v with key on but go to 10v with crank. This includes the solenoid wire.
    Something is up with the neutral safety switch or solenoid.

    I read up on the solenoid a bit and then need a ground, mine is mounted my plastic battery box so I added a ground jumper to the battery directly and out of nowhere it started as it should.

    Now things get interesting... The starter side of the solenoid gets 22v, enough to crank the car but too much volts Im assuming. most everything seems fine but the starter wire keeps power and should not, nor should it be 22v with key on and at crank.

    Any thoughts? I'll try to bypass the solenoid tomorrow and see if that works and or bypass the neutral safety switch.


  2. #2
    Join Date
    Nov 2011
    Location
    Wylie, Texas
    Posts
    179
    Country Flag: United States
    Do you have a good ground (0/1 wire) from the battery to the frame and another good ground from the engine block to frame?

  3. #3
    Join Date
    Jul 2017
    Posts
    131
    Yes. All the grounds are correct and abundant. Thanks for the suggestion.


    Update: adding the ground seemed to fix the issue. As for the strange voltage i experienced after adding the ground, my father in-law suggested i put a load on the wire with high voltage using a test light while using the volt meter. If the voltage on the volt meter dropped to O then i was good, if it did not drop we had a bigger issue. He said volt meters act funny sometimes but this will help determine the problem.

  4. #4
    Join Date
    Nov 2011
    Location
    Wylie, Texas
    Posts
    179
    Country Flag: United States
    With the key not in the crank position then the starter side of the solenoid is not connected to anything so the voltage on that terminal may not be 0V. I think the 8V you are seeing is just stray capacitance in the wiring. If you place your finger on the bare part of the positive probe of the multi-meter while you're taking the measurement you should see the voltage change as the capacitance discharges through your body or your father in-laws suggestion will also work. Likewise terminal 4 is an open circuit so the voltage may not be 0V either.

    The fact that you're only getting 10V on the purple wire while cranking makes me think the battery is not fully charged or is bad.

    I'm confused by the 22V you see on the starter side of the solenoid while cranking as this contradicts the 10V you claimed earlier. The 22V while not cranking could also be stray capacitance combined with you high impedance multi-meter since that is also an open circuit when not cranking. I suspect you may be wrong about that measurement.

  5. #5
    Join Date
    Jul 2017
    Posts
    131
    When i hooked up the ground on the solenoid all the 10v went back to 12v somehow some way. The low voltage could have also came from a low battery like you mentioned, it was at around 70-80% at the time and i was In the process of still charging it. The charger was not hooked up while gathering the volt readings.

    I’ve done two heat cycles and a remote tuning session and everything is fine now. Thanks for the input.