JayM

History

1991 Jeep 144,000 miles Never had an issue till now.

Two months ago I was getting a 42 error, low voltage onthe Auto Shutdown circuit. This occured on the way home from a 20 mile round trip, she just shut down in the middle of the road, and would not restart. I replaced the Original relays under the hood, and now I have a new issue.

When I try to start the Jeep, I hear just a click (like not enough amps in the battery), but all electric to the Jeep shuts down.

The only way to get electric back to the Jeep is to disconnect the batteries, ad touch the leads together, then reconnect the batery.

I have replaced all of the black cube fuses under in the engine compartment fuse box, and the one on the fender well.

I have confirmed that the fuel pump is running (also replaced that).

I have inspected the wiring for obvious rub point and found none.

I do need your help, hopefully someone out there can help.

Q. If the started was shorted to ground, would this cause the relay to shut down the electricity?

Q. How do I check for the starter being shorted to ground? ( I guess I could ohm the selonid to see if it is shorted, I guess)

Thanks for you input guys.

okcjeeper

I had this same issue..replaced the relay, checked the sending unit it was ok but relay seemed to fix it then a week later the fuel pressure regulator went out. So that's a possibility. Get a voltmeter and start checking the relays and the sending unit plug.

JayM

okcJeeper

Which sending unit?

BTW my starter selonoid was shorted to ground, just replaced it, and now, same issue, click, and no electricity.

okcjeeper

Now have you pulled the battery and had it tested? Have you tried to jump it? Also you could pull the starter and have it tested.Also could be an alternator since all power shuts down.. I'd start by trying to jump it, if it starts then you need to look at the battery or alternator if no start starter. Anyways just my thoughts..

JayM

I just had the starter test and had a bad selenoid. Replaced starter andselenoid.

My battery is a little old, maybe 5years< I will go try to jump it.

I did find a broken control wire leading to the coil, but I fixed that.

JayM

ok just tried to jump it - no go, however noticed a few things...

The tach does not move while cranking
Cranking is real slow, not what I am used to.
I was jumping off a diesel so voltages were good.
The water temp guage goes max
The fuel gugage reads half tank, and that is what is in there.

The crank position sensor I replaced ith the clutch 7000 miles ago.

Does the tach move when cranking normally?

The battery is wasted but it's old.

JayM

Bump - any ideas?

I could really use the flow chart of the electrical system.
They show the logic the computer uses to allow the start.

BTW, while cranking there is no fuel in the rail, but the fuel pump starts whent he keys is int he iginition.

JayM

Bump

Does the tach move while cranking normally?
Can some one check for me?
Just pull your Fuel pump relay, and crank the engine, see if the tach moves.

Thanks

JayM

Bump - Does the tach move while cranking?

LimitedXJAddict

I don't know if 91's came with the factory security, but my 92 limited has it... and if the battery voltage goes low or get interrupted it will trip and do the same thing, and sometimes doesn't flash the lamp on the dash. Try locking then unlocking your door from the outside with the key in your driver and passenger door. HTH

okcjeeper

Yes 91's have the stupid factory alarm..I hate it, it is the bane of my XJ's existance but can't be bypassed by grounding a wire..

JayM do you happen to have a Haynes or Chiltons? They both have some electrical diagrams..

JayM

Yep got a chiltons, but no factory security system.
I have seen how that acts, but do not have on, and no light on dash for it either.

Does the tach move while cranking?

okcjeeper

I'll check when I leave school..I never pay attention..

LimitedXJAddict

How much is it moving? If its bouncing around a little thats fine, if you flip the key to start and the tach jumps to the other side or goes above about 3k rpms then it could be an indication of a problem. Not a clue what though as I've only seen mine bounce a little while starting normally or peg out when that stupid factory alarm is on... course my tach almost always gets mad and stops working for awhile after I do a water crossing :P

JayM

LimitedAddict
No bounching, no movement at all.
My Speed O stops workign for a while if I reverse then grab first without fully stopping. 5 speed.