This jeep is possesed....1990 2 wheel drive straight 6cyl. 4 ltr cherokee with auto,,,,,,,Drove it home and no problem. Next day dead. Checked and had corrosion on possitve battery post. Cleaned cable back to clean and replaced head. started and ran. Left running to help chg batery and then went to bed. Next morning dead again. HERE'S THE WEIRD PART. wont jump..tested battery perfect. was going to do tune up anyway so...replaced plugs, wires, cap and rotor and COIL...still wont crank BUT if you pull wire from top cap to rotor, the engine tries to turn over!!!!!!! Jeep dealer is scratchin his head too. I am so twisted over this. Any help would be great.

 

bad alternator?

 

Bad starter.

 

X2 bad starter and alternater

 

Ok update. .. starter and battery replaced. . Now will turn over but not fire. Checked fuel pump.when I bypassed ignition it will work and jeep will run.
Now, where do I look? Relay or fuse link or ecm....aaaaaaaaaa
Tired of throwing money at it

Ideas?

 

I had sort of the same problem with my jeep cherokee. Most likely your starter or alternator in this case.

 

could be your cps so i would try cleaning it and putting a meter to it. I would also reset your ecu (google how to its easy). If not id start from the basics, good fuel pressure? Air filter and throttle body clean? getting spark to the plugs? All engine grounds clean and on good connection point? Also try starting it in neutral instead of park (friend of mines did that a few times for whatever reason). keep us updated

 

How did you bypass the ignition?

Renix ECUs are not resettable.

You have spark but not fuel?

 

good call forgot it was a 90