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Hot Rods Perplexing electrical issue, runs for a minute then completely dies...

Discussion in 'The Hokey Ass Message Board' started by xadamx, Sep 28, 2015.

  1. xadamx
    Joined: Apr 18, 2003
    Posts: 1,170

    xadamx
    Member

    It's been a while since I've posted here, still lurking though. My '31 Ford coupe just died on me after running perfectly fine for years. It started and drove normally for about 90 seconds and...idling at a light, it shut down. Everything. No lights, no electric fuel pump, no starter. I pushed her to the side of the road and a minute later, I had complete electrical power again and was able to get to work. I tried again in the parking lot...started and ran for a minute or so then, same thing. No power of any kind. I checked the battery and grounds, all fine. It's fully charged. Bad cell? Starter switch? Solenoid? I don't know, thought I'd ask some experts before I tear into it. Here are some details:
    -8BA flathead
    -12v with a Powergen alternator
    -Battery in trunk
    -Grounded from battery to frame, transmission to frame
    -Electric fuel pump

    Thanks a lot!

    Adam
     
  2. squirrel
    Joined: Sep 23, 2004
    Posts: 55,931

    squirrel
    Member

    Did you take apart all those battery cable, and ground connections? searching for corrosion, loose bolts, etc. This is the most likely culprit.
     
  3. xadamx
    Joined: Apr 18, 2003
    Posts: 1,170

    xadamx
    Member

    Indeed...thanks for the reply. I will be going straight to those culprits as soon as I get home!
     
  4. abner36
    Joined: Nov 5, 2014
    Posts: 77

    abner36

    Do you have battery disconnect switch ? maybe corrosion there?
     

  5. xadamx
    Joined: Apr 18, 2003
    Posts: 1,170

    xadamx
    Member

    No disconnect switch...but it feels like I have one that doesn't work! Ha.
     
  6. I keep thinking something like a relay that's failing or a circuit breaker that's getting weak and tripping and resetting itself. But that would tend to affect maybe just a single circuit and not shut down everything electrical.

    Keep us posted on what you find... This could be a doozy! :eek:
     
    loudbang likes this.
  7. xadamx
    Joined: Apr 18, 2003
    Posts: 1,170

    xadamx
    Member

    As Squirrel suggested, I looked at the ground from battery to frame...it was a tad loose but grungy. I just cleaned and sanded the areas and made sure there was good contact. I'll report back when/if I get home! Thanks, all!
     
  8. xadamx
    Joined: Apr 18, 2003
    Posts: 1,170

    xadamx
    Member

    Nope. That wasn't it. It still totally died after 25 seconds. It always starts back up after 5 minutes or so. And as I said before, it's been perfect for 7 years and never had any symptoms like this.
     
  9. Fedman
    Joined: Dec 17, 2005
    Posts: 1,163

    Fedman
    Member

    Can you switch out your battery and rule that out?
    They can cause stuff like this if they are shorting out internally.
     
  10. xadamx
    Joined: Apr 18, 2003
    Posts: 1,170

    xadamx
    Member

    Something at the hot side of the starter solenoid? The smaller hot wire that comes to the same post as the + battery cable runs through a blue 60A fuse that seems to be ok. No access to a battery right now, Fedman.
     
    Last edited: Sep 29, 2015
  11. RAW
    Joined: Dec 13, 2009
    Posts: 4

    RAW
    Member
    from Maryland

    What kind go fuse box are you running? I had a truck that the main harness bolted together through the firewall and it came lose cause similar issues
     
  12. Engine man
    Joined: Jan 30, 2011
    Posts: 3,480

    Engine man
    Member
    from Wisconsin

    Without knowing how it's wired it's difficult. It almost sounds like there is a circuit breaker in the system that is tripping out and resetting when it cools off. The ignition switch could be bad and switching it off and on brings the power back but that should work right away. There might be a relay that gets hot and drops out.
     
  13. VOODOO ROD & CUSTOM
    Joined: Dec 27, 2009
    Posts: 1,287

    VOODOO ROD & CUSTOM
    Member

    I have had Battery cables corrode internally and cause all kinds of weird electrical
    stuff as you describe. It may be worth testing the cables for resistance. You mentioned that
    one connection was "crusty". I'd check that cable for corrosion "inside" of the wires.

    VR&C.
     
  14. hacknwhack
    Joined: Jan 25, 2006
    Posts: 481

    hacknwhack
    Member
    from mass

    My thoughts exactly.

    Is that"blue fuse"actualy a circuit breaker ?

    Placing test lights and meters strategically around this area may help finding the open circuit under load.
     
  15. xadamx
    Joined: Apr 18, 2003
    Posts: 1,170

    xadamx
    Member

    OK, just got home, it started right up. I only had to drive a short distance, so I kept the RPM's up. I got in the garage and let her idle, she did for about a minute and then I noticed the voltage was dropping and she was starting to die until I gave her some gas, and the gauge shot up to 16 volts...back below 12 when I let off the gas. I shut it off and went to restart, nothing. No juice anywhere. An hour later, full juice and started right up as usual. That's where I'm at, now. Sorry if overly detailed, just trying to describe the symptoms.
     
  16. 57countrysedan
    Joined: Oct 28, 2012
    Posts: 370

    57countrysedan
    Member
    from NY

    If u are losing everything then I'd have to guess bad battery connection. If when it dies and u still have headlights or some other circuits then I would thing ignition circuit. Because I would think if it was the alternator/generator then u would have to jump it to get it running again.
     
  17. I'm going to make the assumption that you have certain circuits wired so they are hot all the time, regardless of whether the ignition switch is on or off. Things like the lighting circuits and horn and cigarette lighter (if you're so inclined).

    Then there are other circuits that are hot only when the ignition is switched on. Things like the ignition, wipers, radio and (probably not so much in your case) heater fan.

    If everything is truly going dead that should pretty well eliminate a problem being in the "always hot" circuit only, or in the "hot with ignition on" circuit only. Which pretty much just leaves the battery and battery cables that feed those two circuits.

    Do you have a conventional battery or one of those fancy gel cell jobs? Any sort of anti-theft shut-down system or any kind battery isolator?

    And as usual, please feel free to prove me wrong. Many folks do... :rolleyes:
     
    Last edited: Sep 29, 2015
  18. xadamx
    Joined: Apr 18, 2003
    Posts: 1,170

    xadamx
    Member

    Thanks for the response, ClayMart. It truly goes dead...no lights, gauges, or fuel pump. 5 minutes later, it's full of life and ready to go...for another 30 seconds. It seems to want to stay running at higher rpm's, but at idle it suddenly shuts down with no power to anything. It is a conventional battery and the date on it is 7/14...only a year old! There is no anti-theft system, it is wired VERY simply...elec. fuel pump, headlights/tailights, brake lights, brights, and three gauges. I'll be heading out to the garage soon to test the battery, alternator, loads, etc.
     
  19. squirrel
    Joined: Sep 23, 2004
    Posts: 55,931

    squirrel
    Member

    The charging circuit should keep it running at higher rpm, even if the battery is disconnected.

    This will be fun to watch....when you finally figure it out.... :)
     
  20. Dan Timberlake
    Joined: Apr 28, 2010
    Posts: 1,530

    Dan Timberlake
    Member

    I'd be armed with a voltmeter to start probing for voltage the next time it dies, starting at the positive battery post, then bat terminal, then opposite cable end, etc. Repeat for the ground circuit. Maintenance cleaning and Visual inspection of connections and cables does not rule out defects. Bad connections etc, can not hide from a voltage drop test.
     
    bct likes this.
  21. abner36
    Joined: Nov 5, 2014
    Posts: 77

    abner36

    From what you described it sounds like the alt is going out over charging at high rpms and dragging or shorting at idle but it doesn't explain the let it set for a bit and all power comes back.
     
  22. Jalopy Joker
    Joined: Sep 3, 2006
    Posts: 31,174

    Jalopy Joker
    Member

    age of battery, or many parts for that matter, does not make any difference. yep, knowing voltage at battery before start up, after starting up and after it dies will tell a lot - that is with a tester, not your dash gauge. the big fluctuation in voltage readings aims to alternator - internal regulator style? may be that alt is not functioning properly along with a marginal battery.
     
  23. you should have a simple system in your car.....if there is anything i.e: relay, solenoid or circuit breaker in the starter, battery circuit then that is the problem. I have run into a similar problem where the battery cable was so corroded inside the insulation it had high resistance and cause starting and running problems.

    40truck.jpg
     
  24. rfraze
    Joined: May 23, 2012
    Posts: 2,008

    rfraze
    Member

    How about connecting a multi tester with jumper wires to the coil+, fire it up, and watch to see if voltage drops before engine quits. Try it again at battery. Alternator. Key.
     
  25. xadamx
    Joined: Apr 18, 2003
    Posts: 1,170

    xadamx
    Member

    OK, I did some multi-metering. With the engine running and the meter hooked to the alternator(Powermaster Powergen), it put out consistent charge but after a minute or two, voltage started jumping all over the place. Now my multimeter appears to have broken! I shut the car off and, once again, now there's no power to anything. When I drove home last night, about 1 mile, I kept the rpm's up and made it home. It idled for a while and then started to die. When it did, I turned the key back on...nothing. No headlights(not even dim) or fuel pump. I'm starting to think it's alternator associated. Possible? I checked all grounds, they are perfect.
     
  26. David Gersic
    Joined: Feb 15, 2015
    Posts: 2,730

    David Gersic
    Member
    from DeKalb, IL

    Sounds like something that works when cold, but fails when it warms up. A voltage drop test should show it. You'll see a little drop initially, but it will rise as the resistance heats it up, until it goes infinite and kills the car.
     
  27. Black Panther
    Joined: Jan 6, 2010
    Posts: 2,133

    Black Panther
    Member
    from SoCal

    I'm thinking it's the alternator too. Disconnect the alternator ...jumper wire your ignition straight to the battery...and run the engine off the battery....the battery should last long enough for you to isolate and test the alternator to see if it's the culprit...
     
  28. canning
    Joined: Jan 22, 2012
    Posts: 72

    canning
    Member

    Batteries do strange stuff. Can't borrow one from another vehicle for a test? Start with the easiest. Then look for a short.
     
  29. 57countrysedan
    Joined: Oct 28, 2012
    Posts: 370

    57countrysedan
    Member
    from NY

    If it is a defective alternator not charging then the battery should stay dead. Do u have a top post or side post battery? I've seen the side posts build up a lot of corrosion between the bolt and terminal. Just a thought. But it really sounds like a connection issue to me
     
  30. stimpy
    Joined: Apr 16, 2006
    Posts: 3,546

    stimpy

    pull the battery and give it a full charge first before trying to test it ( biggest mistake is trying to find a problem with low voltage) , after charging the battery do a load test on it ( use a milton toaster box style one ) , batterys can go bad in a year some in several days in a car from vibration and bumps knocking the lead paste out of the cells and shorting or causing intermident shorts in the plates ) after the batter passes a load check then recharge it and test the alternator . you need current to make current , when you start the car the alt should read in the 14.8 v area and then slowly trickle back to the 12.8- .12.5 range , if it dips below that its bad .
     

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