Jeepin_On_Ice

Hi all, I’m at a loss with what’s wrong with my jeep so I figured I’d ask more knowledgeable people than myself. This is probably going to be a little long so I apologize in advance, just don’t want to leave out anything that might help.

Alright, so yesterday I went to start up the Jeep, (1996 Jeep Cherokee Sport, AX-15, I6), and the battery was fairly dead, I got a few cranks out of it and that was it. It’s the beginning of winter and about 30 degrees out and the battery is about 4 years old so I figured time for a replacement anyway. I replaced the battery and it fired right up and ran for about 15 seconds, then cut out just liked you tuned the key off. No dash lights, no gauges.

I turned the key off and back on but none of the idiot lights come on. The only light on the dash to come on when you turn the key is the seat belt light. So, upon turning the key I get no check engine light on the dash, no fuel pump running(no pressure at the rail either), no spark (I checked at the distributer) and no attempt to start(just a lot of turning over). I tried to do the key trick, as I’ve done it before on this jeep and it worked, but I get nothing now, the check engine light never comes on. I replaced the alternator about a month ago if that makes any difference. Also, if it means anything, the PCM was replaced by the previous owner in 2006. The jeep is my only vehicle so I’m hoping to get this thing running again soon.

Thanks, and sorry again for the long post!

ezab

Did you check all of your fuses?

N20jeep

check the terminals for loosness or corosion.

you dont get anything on with the key in the "on" position? radio, lights, gauges?

Jeepin_On_Ice

Ive checked the connections and battery terminals and cleaned them all, still nothing.

With the key in the "on" position, everything else works, the radio, lights, gauges, door buzzer. Just no idiot lights on the dash and no fuel pump running when you first turn the key to "on" position.

ezab

You could check for voltage at the pump or jump the fuel pump relay to see if you have a bad fuel pump.

Frostracing

x2

If it's still cranking like it wants to start and nothing else works it seems like your ignition switch died or some junction in your fusebox. I would try the accessories like radio and windows and if those work with the key in the on position I would check the fuel pump circuit with a simple tester. Whatever it is probably killed your old battery.

Jeepin_On_Ice

With the key in the "on" position and in the accessory position, the radio, interior lights and horn all work. The jeep has manual locks and manual windows so i had to use something else I also jumped the fuel pump and it worked, so its just not getting power for some reason. The fuse and everything is good, so as far as i can tell its just not getting power applied to tell it to run. The fusible link and connections in the fuse panel under the hood appear to be good, wiring is in good condition. Will start testing circuits as soon as I can get it someplace warm, aka: out of the wind

Thanks for the help so far

Jeepin_On_Ice

Braved the cold today and did some testing on the Jeep. So far I have found that the ignition pickup, Cps, and tps are all good. I checked the fusible link and it was good to. All connections in the PDC are good and clean and all relays and fuses are good. Still, the only light on the instrument pannel to come with the key in the "on" position is the seat belt light, so I am assuming that the pcm probably the problem? Any ideas?

Frostracing

Definitely a weird problem. If it were my car I would trace the fuel circuit all the way from the pump to the ignition switch and see where power cuts out. Not an easy thing to do without a diagram and because you need someone to crank it every time you check a new spot but necessary. Also, did you check your grounds on the engine block? there are two on the passenger side on my 87 XJ.

MATT 87 CHEROKEE

Hate to say it but it sounds like the computer died... its happened to me 2 times

Jeepin_On_Ice

This is the conclusion I have come to. Checked wires and the computer is getting power but won't connect to and OBD2 scanner.
How bad was it to replace the computer? What has to be done to the replacement computer?

MATT 87 CHEROKEE

The worst part of replacing the computer is paying for it they are not cheap but you can look on craigslist for a cherokee being parted out you will have to make sure it is a year that will work with yours and has the same size motor and same type of tranny I got my last computer for 40$ but they are very easy to install its literally plug and play but it may run a little rough for a week while the computer is "learning"

Jeepin_On_Ice

SO as long as I get a computer from a cherokee that has the same motor,trans and is the same year it should work? Would it have to have the same options as mine does, such as no abs, no cruise, and manual windows and locks? Just want to make sure i get this right, I've never done much work with the computer system in these vehicles.
Thanks again for all the help!

subliminal1284

Check your cat, it may be clogged

MATT 87 CHEROKEE

Your welcome, the only option that should matter beyond motor and trans is the anti theft system ill do some calling around to make sure and post the results