Need Help With 97 4.0, Very Strange Problem

[Jeep Driver]

As stated in my other thread, the MAP sensor went out in my wifes XJ, high idle.

 

Bought new one and installed it when the wife got home.

I touched nothing else but the MAP itself.

 

When I got in to start it I got one click from the starter and the head lights came on, everything else went completely dead. No instrument lights, no dome light, no radio......nothing.

 

I disconnected the battery, reconnected, turn key to on and everything is normal, turn to start and one click, head lights come on, all goes dead.

 

I moved relays around, checked every fuse.....

 

 

Rinse........repeat.......same result.

 

Any ideas?

Thanks.

 

 

Also.....battery is good but I hooked up charger in start position with no effect.

 

And.....head lights stay on with drivers door open.......close door........head lights go out.

[Jeep Driver]

Narrowed down to this-

 

 

If I disconnect the battery for 15 seconds and reconnect, I can reach in and turn the key on and everything appears normal, idiot lights light up and fuel gauge comes on (no head lights but I can turn head lights on and off that the switch).

 

Once I turn the key to start, I loose everything and head lights come on.

[Jeep Driver]

Solved my problem.

[johnr]

:popcorn:well

[Eagle]

Solved my problem.

Please post the explanation so if anyone else encounters it, we'll all know.

 

That's how these forums share information.

[Jeep Driver]

Sorry, had a hungry family that was waiting to go out to eat.

 

 

Here's the deal-

 

Wife and I left separately for work this morning, I ran into her at the post office just as she was leaving, that was the first time the XJ acted up with the high idle. I unplugged the MAP and told her to drive the two remaining blocks to work.

 

Tonight she calls from a block away from work, the XJ won't make it with the MAP unplugged, I run there and plug it back in.

 

She pulls up to the garage and I replace the MAP.

Get done and I tell her to start it up, that's where the problem began.

 

 

 

I'm usually pretty good and figuring out this kind of thing on my own.........but the head lights coming on......that through me for a @#$%ing loop.

 

 

At first I thought that by running with the MAP unplugged then plugged in, then unplugged......well........maybe I caused it to go into automatic shut off mode, that's why I began to disconnect the battery.

 

The XJ at one time had an alarm system, so then I thought maybe I somehow sent it into a no-start anti-theft mode....again, with the head light coming on and no start, so then I go pulling panels off looking for the module.

 

Stumped.

 

Next I decide since the car would act normal with the key in the on position, I would go ahead and see if I could trigger the starter and turn the engine over to see if it would run independent of the ignition switch. When I connected the trigger wire to the Pos side of the battery......again.....nothing.

 

 

 

 

Several months ago when the XJ needed a new battery, the original battery clamps were destroyed and being in a rush at the time I got a pair of the wire clamp style post connectors. As much as I rail against using them.......again, we were in a rush to go somewhere as is always the case.

 

 

As many times as I disconnected the battery tonight the wires never appeared to be loose, clamped tightly to the post connector........but something told me to really wrench them down.......I did and the problem was solved.

 

 

 

I'm still stumped over why the head lights would come on........cannot for the life of me figure that one out.

 

 

Next project......new wires and soldered lugs, just as I did for the MJ.

[Automan2164]

I'm coming in here late as have just read this post for the first time, but as you were describing it in the first few posts I kept thinking battery connections or battery... Having operation until the large draw of the starter was a red flag for me.

Glad you figured it out.

Rob :cheers:

[jeephack]

I recently purchased a '97 ZJ for $250. The PO had been having problems wiith the "fuses & relays" in the fuse block behind the battery and could

never get it figured out.  I brought it home and replaced both battery cable ends and now I have a really good clean Jeep for $250!