Markcld7

I'm having intermittent starting and delayed starting. I have tried different keys, resetting the wcm, bumping the shift lever, and checked grounds and battery. Initially I place the key in ignition turn to start all the lights and dash lights will come on, but engine (starter) will not turn over. You can hear the relay click. Tried to start several times. no luck. Jumped off with no problem and worked fine all day. Next morning same thing. Next day I got my voltmeter checked everything cleaned grounds no luck. Then when checking a couple more lines I had tried to start with no luck. I got out of the Jeep walked around to front of Jeep and just like magic it cranked. help! 2009 wrangler 3.8l. Battery and starter is less than 1 year old.

Mr.T

I'd start troubleshooting by checking the voltage between the two wires on the starter motor and the motor case, when the problem occurs.

The large red wire comes from battery + and should always be reading battery voltage, less a bit of voltage drop when the starter is actually cranking.

The smaller wire (Yellow w/ Gray) comes from the TIPM. It should go positive to run the starter motor.

The motor case is (should be) grounded to battery negative. You can check that by putting a voltmeter from the starter motor case to battery negative, it should always read around zero volts except during cranking -- guessing less than 1 volt drop while cranking.

If it passes all these tests and doesn't crank, it's a problem in the starter motor. And if you bought a rebuilt starter motor before, that's what I'm betting on.

Here's a diargram I plucked off the internet, not exactly what's in my manual but close enough.