I Did a engine swap in my 2008 jk, I installed the same motor just out of a 2010 jk. I used the TIPM, wiring harness, ac compressor, power steering pump, altenator, and starter from my 2008 motor, and am having issues with the starter. Without the key in the ignition the motor started cranking as soon as I connected the battery terminals to the battery, and continued until I unhooked the terminal, which was only seconds later.


HELP PLEASE!!!!

 

check the starter solenoid. as you know it closes with the turn of the key allowing voltage through the big cables. if there is 12 volts before you have the key you have a short in the ignition. if the solenoid is closed without the little wires on the solenoid is bad. it may be even as easy as the starter being hooked up backwards so that as soon as the battery cable gets attached it cranks. get the multimeter out and poke around. good luck.

 

Check the connections at the starter. One is battery positive(big terminal) the other is switched 12volts from the starter relay. If your battery terminal is touching the smaller terminal it will continue to crank untill the battery is unhooked.

FYI. The PCM controls the starter relay.

 

I had the starter replaced and it still did it! Come to find out, the power wire was touching the s terminal when it was tightened down...!!! Boy my mechanic friend felt stupid. Starter needed replacing anyways so no big deal. Thank you guys for the help.