89 kenworth starting problems

Discussion in 'Kenworth Forum' started by wyatt earp, Jul 13, 2011.

  1. wyatt earp

    wyatt earp Bobtail Member

    Jul 13, 2011
    Hello all, started my cabover 2 days ago and it started fine. Now i have to unhook my batteries when not in use or it will drain my batteries. NO big deal since this truck is only used for a farm truck to haul my 7300 horse trailer.

    Today i went out to pull it forward to get the trailer up on a ramp to change the tire and it will not start. It just wants to CLICK and that is all. I knocked on the starter and it still will not start. I need this truck for this weekend. What else could be wrong besides the starter, I could see the bedix engaging but the starter was not spinning. any help would be great
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    DAVERAMIREZ3406 Bobtail Member

    Jan 3, 2011
    Make sure all your cables are tight ,if one is loose and not clean they wont get a good contact to the starter.
  4. Sparkz

    Sparkz Light Load Member

    Jul 10, 2011
    New Zealand
    I assume the starter is a 12volt Delco 40MT, 42MT, or 50MT.
    Battery positive on large stud on top of the solenoid.
    Battery negative on the large stud on the rear of the starter. Also earth wire from here to a small stud on the solenoid.
    Starter energising wire on another small stud on the solenoid. This wire goes to a starter slave relay, usually nearby on the chassis or firewall etc. This relay has a positive cable on its other stud. The start button operates this relay which closes its contacts and powers up the energising wire to the main starter solenoid. The starter will then crank the engine.

    To test the system connect a voltmeter to the main positive and negative studs on the starter. Voltmeter should read at least 12volts.
    Press the start button and see if the voltage drops. If the starter doesn't work, but the voltage drops substantially you have problems in the main battery cables, isolation switch, or batteries.
    If the voltage doesn't drop by much, move the positive voltmeter lead to the solenoid energising wire.
    Press the start button again.
    If the voltmeter reads about 12volts with the start button pressed, the starter is faulty.
    If the voltmeter doesn't show any voltage it means that the relay is not working. This could be a faulty relay or wiring to it from the start button.

    Check for dirty connections on the copper link from the solenoid output stud to the starter fields. I have also seen this link break on Cummins engines.
  5. cessna5354

    cessna5354 Bobtail Member

    May 9, 2010
    Southern NJ
    You can remove the stater solenoid, inside there is a contact disk which makes contact at 9:00 & 3:00. You can rotate this disk one quarter turn to engage new contact surfaces to get you going.

    Good Luck
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