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Technical 39 Pontiac electrical help

Discussion in 'The Hokey Ass Message Board' started by fyrffytr1, Aug 8, 2020.

  1. fyrffytr1
    Joined: Dec 20, 2016
    Posts: 834

    fyrffytr1
    Member

    I started my 39 Pontiac this morning and it ran for about 15 seconds then died. There is no power to the electric fuel pump or to the coil. I couldn't find a fuse panel nor any fuses anywhere. Battery is good and fully charged. Anybody here have an idea of what I need to look for? It's still a 6 volt system and it ran last week for the first time in 50 years. I even drove it around the backyard.
     
  2. squirrel
    Joined: Sep 23, 2004
    Posts: 55,942

    squirrel
    Member

    first thing to check is the the battery cables. First clean the terminals at the battery, then where the big fat cables connect to the terminals, then the other end of the big fat cables, where they connect to the engine/frame/body and the starter solenoid. 85% of the time this is the problem with a sudden loss of power.
     
    6-bangertim, VANDENPLAS and fyrffytr1 like this.
  3. fyrffytr1
    Joined: Dec 20, 2016
    Posts: 834

    fyrffytr1
    Member

    I have new cables that I will install tomorrow. Thanks for the help.
     
  4. squirrel
    Joined: Sep 23, 2004
    Posts: 55,942

    squirrel
    Member

    Did you get the correct cables? 6V systems use thicker cables than 12v systems...if the cables are undersized, it might have trouble spinning the starter motor fast enough.
     
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  5. David Gersic
    Joined: Feb 15, 2015
    Posts: 2,730

    David Gersic
    Member
    from DeKalb, IL

    Electric fuel pump, in a 39 Pontiac. Sounds non-stock...

    Guessing you didn’t build this. So what do you know about it? Does anything electrical in the car work? Headlights, horn, dome light?

    If it was rewired, there should be fuses somewhere. Follow the harness and find the fuse panel. Could be that you’re looking for a fusable link, not an actual “fuse”.

    If it wasn’t rewired, you may be in for more trouble down the road, depending on the conditions the wiring, and what has been done to it.



    Sent from my iPad using The H.A.M.B. mobile app
     
  6. Start at the battery and follow the cables back to where the power stops.

    muse a multi meter to check actual voltage as you could have a bad or loose connection somewhere.

    anything else not working?

    your car likely did not have a fuse box from factory and the electric pump is an add on.

    not slot of wiring on your car really so tracing it all back from the battery or ignition switch should not be an issue.
     
  7. fyrffytr1
    Joined: Dec 20, 2016
    Posts: 834

    fyrffytr1
    Member

    Thanks for all the tips. This car has been sitting for 50 years. I have had it about five. I took the entire front clip off to gain easier access to the motor. All original wiring except for what I have already replaced. I went back out to the car today and still no power to the electric fuel pump I recently installed just to get the motor running. But, when I step on the starter button the starter spins. I am leaning towards a bad switch or maybe an inline fuse somewhere. I'll try to get my 70 year old butt up under the dash tomorrow and check things out.
     
  8. For 6 volts. An Ultima 6 volt and 00 battery cable made up works wonders. It would make it turn over like a 12 volt.
     
  9. squirrel
    Joined: Sep 23, 2004
    Posts: 55,942

    squirrel
    Member

    you could use a test light or volt meter to find where the voltage stops...
     
  10. The fuse panel for those early GM cars usually consisted of a couple of fuses mounted on or near the headlight switch. You can always disconnect the input to the fuel pump and wire it direct to the battery to get you going. Don't forget to put in some sort of safety switch in case of an accident!
     
  11. fyrffytr1
    Joined: Dec 20, 2016
    Posts: 834

    fyrffytr1
    Member

    I am not getting spark to the plugs and nothing to the coil. I will check out the car this afternoon if I can get my other chores done.
     
  12. fyrffytr1
    Joined: Dec 20, 2016
    Posts: 834

    fyrffytr1
    Member

    I found my electrical problem. The entire wiring harness under the dash is mostly bare wires! I unhooked everything from the ignition switch then added a new 10 gauge wire with an inline fuse holder from the battery to it, and then ran a wire from the switched side to the electric fuel pump. The coil wire actually comes out of the center back of the switch and is enclosed in a metal cable so I left it alone. The car cranked and ran but I found another problem that I am going to post in a new thread because it is carburetor related. Again, thanks for all the help.
     

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