Jeep has weird starting habit!

Discussion in 'Shop Talk' started by r.h. in okla., Apr 21, 2005.

  1. I can get in it and it will start just fine. If I drive it 2 miles or less and turn the engine off it will not start. I have to crawl underneath the jeep with a screwdriver and short two post on the solenoid to start it. If I drive it more than 2 miles, stop, turn it off then it will start right up with no problems. So whenever I drive it I have to make sure I travel more than 2 miles before turning it off. It has been doing this for about a year now. When it does start on its own there appears to be no problem with the solenoid at all. So do you think it I need to replace the solenoid or do you think it is some other problem? I would think if it was the solenoid it would get to where it wouldn't start at all no matter how many miles its droven.
     
  2. agmantoo

    agmantoo agmantoo Supporter

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    RH, a stab in the dark! My best guess is that it is a voltage related problem. Batteries will recover some on their own in some situations like over night. For example, you can discharge a battery to the point it will not crank the engine over, let it rest for a duration (over night) and in the morning it will again crank the engine over. That said and going back to your problem, it cranks, runs, but then refuses to crank on brief trips. The battery was discharged with the initial start and the short trip does not allow the alternator to "rebuild" the charge that was taken from the battery at initial startup. After driving for a longer period the battery has had sufficient time to recover from the original crank and the voltage is back up. When you jumper the terminals on the starter solenoid the coil in the solenoid is bypassed and whatever current is in the battery is delivered to the starter and the vehicle cranks. The coil in the solenoid is voltage sensitive and the starter is less sensitive. I would first substitute the battery for a trial test. A spent battery could cause this unusual condition. A bad starter solenoid could also behave in this manner IMO.
     

  3. farminghandyman

    farminghandyman Well-Known Member Supporter

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    why do you think my son and son in law call there Jeeps Heaps, LOL

    try the battery if you have a spair, and then try a solenoid (they usaly are not to expensive) it could also be heat related problem, something could be getting hot and expanding and breaking contact, check all connections, check from the key switch all the way to the solenoid, and then down to the starter,

    check the ground wire for tight on the battery and the motor block, check the battery terminals for clean and the cables,

    does sound odd tho,

    just for the information my son did buy a "Found on road dead",as his jeep was getting to act like the other acronym for "Ford". "Fix or replace daily",
     
  4. John Hill

    John Hill Grand Master

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    Agnman could be right but there are other possibilities.....

    For example, when started with the key the coil is fed full battery voltage while the key is in the 'start' position. When starting by shorting the solenoid the key is in the 'run' position and the coil is getting feed via the ballast resistor. Maybe the resistor has a temperature problem? Maybe the coil is installed incorrectly? Usually reversing the primary connections to the coil will make no appreciable difference except starting problems when hot, maybe this is related?
     
  5. Rick

    Rick Well-Known Member Supporter

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    Hi RH

    Here are a couple of thoughts. You can use a multi-tester to determine the voltage of the battery the morning after a long drive, after turning the engine off after a 2 mile trip, and after turning the engine off after a longer trip.

    In terms of general efficiency it is best to avoid such a short trip; I'm sure you know that. We can't always arrange things that way though.
    It is also best to not drive less than 5 miles or moisture will sit in the system of exhaust pipes, encouraging rust and corrosion.

    Rick