Starter can be jumped ONLY when key is 'OFF'; Key 'ON', starter direct jump fails
 

Jeep wasn't starting so after some test I replaced battery/terminals. When I turn the key the radio turns off and when I release the key I hear a click.

I've brought the starter in to get tested and starter/solenoid work on the bench.

The interesting part (to me):


TEST ONE

-Key Off
-Battery terminals connected
-Battery ground to starter housing direct
-Battery positive to starter motor positive (directly to lead, not through bolt)
----------------------------
RESULT: The starter motor spins up


TEST TWO

-Key 'On' (not accessory, not held forward at ignition position)
-Battery terminals connected
-Battery ground to starter housing direct
-Battery positive to starter motor positive (directly to lead, not through bolt)
-----------------------------
RESULT: The starter motor does nothing, and the positive terminal lead I am holding (jumper cable connected to starter positive) is smoking and sparking a lot.

NOTES:
• Manual transmission
• Fuses seem fine
• Have checked SOME grounds

What's weird to me is that having the key in the ON position somehow overrides my ability to jump the starter motor directly. This makes me think that somewhere I have a bad ground or am somehow powering my chassis, but I don't know enough to be sure about that.

Does anyone have any ideas?

Thanks, Kevin

when i had start trbl with the starter mounted and wired properly i could jump the hot bolt on the starter to the small ignition/start connection. it always cranked.
i might sometime get a click from the start relay but no crank. took the reman starter back for a NEW one.

no more trouble , starts every time
mount and wire normally, then test.

.

OK, I think I see your point, that it could be bad even though it tests ok? I'll keep that in mind.

Any thoughts on why having the key at 'ON' would stop me being able to jump the starter motor? I described it a bit in the original post.

Before I buy a new starter I want to make sure it's not just a bad ground or something unrelated to the starter itself.

? on that,,i have no ign sw trouble,,now!
you need to check it for proper output,,??
i think you should be able to jump the starter anytime like i did,the hot wire to the small start connector should crank without the key.even my reman would usually crank that way. thats how i had to start sometime. i could put key in the on/run position and go out and screwdriver jump it and it ran.

i was thinking of adding a jumper and pushbutton but that got crazy! lucky me i got the new for same price,even swap. good store.

starter is grounded when bolted in. check batt neg cables, it should jump crank anytime.

"When I turn the key the radio turns off"
If the headlights also turn off, then you still have a bad battery or bat cable connection problem.

Go thru all your grounds,esp. battery and starter cables,check and charge the battery.

sounds like the batt is ok

If the bench test was good then you need to check your wiring to the starter. Something is not right and most likely shorted which is why it's smoking.

Odd one alright. So...jumping to the solenoid terminal makes it crank, key off, but smokes key on. If a power wire to the switch, or the switch it's self is grounding that could ground the power you are jumping to the solenoid. (Key on)..

Why are you grounding at the starter it's self is a question.

Power to the switch goes through a fusible Link, pretty sure. IN here you might find something helpful

> A BUNCH OF JEEP WIRING DIAGRAMS. (THANK YOU TOM!)> http://oljeep.com/gw/elec/cherokee/edge_cherokee.html

Haha because I'm still working out all this mechanic stuff, first car to work on after working on vintage motorcycles. I suppose I tested it that way to rule out a bad vehicle ground causing trouble. Meaning, to test the starter directly without depending on anything other than my own jumped hot and ground.

Thanks for all the answers and help, I got home from work today, cleaned up and reinstalled the starter and the Jeep fired up fine. I suspect I either had a bad ground (doubtful, I barely adjusted the ones I checked) or grease/grime build up was causing troubles with the starter contacts. We'll see though, could be the starter or relay is beginning to fail.

Cool, glad you got her runnen!