Oh no! What'd I do?!
Seasoned Member

Joined: Sep 2013
Posts: 280
Likes: 1
From: Santa Clara, CA
Year: 1987
Model: Cherokee
Engine: 4.0
CF Veteran
Joined: Oct 2011
Posts: 1,268
Likes: 1
From: Bakersfield CA
Year: 1990
Model: Cherokee (XJ)
Engine: 4.0
You can have a no start with spark if the switch will allow the engine to crank w/o firing up(it acts like a bad MAP sensor). Have you not had one of our wonderful ignition switches short out yet?
trace the wire you shorted, where does it go? get a wiring diagram.. if you shorted a injector 12v feed wire, that voltage feeds everything, it has to be the feed wire, as the other wire is a computer trigger / ground, grounding it wouldn't do anything, except fire that injector if it was plugged in.. that 12v feed wire comes from the ASD relay, (at least if its like mine) it also feeds the alternator, and some other things.. I suspect nothing is fried past a fuse, the wire, or possibly the ASD relay.. if you were to manage to short both injector wires together that could fry the triggering transistor in the ECU for that injector only, but I wouldn't see it do much else.. take a test light and probe all the fuses, they should have power on both pins when plugged in with the ignition on the run position. Just looking at the fuse isn't good enough at times..
Last edited by Oddballmotorsports; Nov 30, 2013 at 06:44 AM. Reason: a lil more helpful...
Seasoned Member

Joined: Sep 2013
Posts: 280
Likes: 1
From: Santa Clara, CA
Year: 1987
Model: Cherokee
Engine: 4.0
Well, like I mentioned earlier, I can't speak for anything other than a Renix, but on the renix, the Ignition and ECU etc are all fed off of one wire from the switch. The way mine's is wired, it would very unlikely that it wouldn't start if it did have spark and was cranking (assuming the ECU etc. is working).
Thread Starter
Senior Member
Joined: Nov 2013
Posts: 503
Likes: 0
From: Jax, FL
Year: 1998
Model: Cherokee
Engine: 4.0L
Here's a pic of your Power Distribution Center. Note the fuse marked IGN RAIL COIL FUEL INJECTORS. Check to see if it is blown.
Also PCM and ASD. Check these as well.
Edit: The fuel injector driver in the PCM for that fuel injector you sparked may be smoked. These FI drivers are touchy and can be smoked even with a low impedance fuel injector.

Also PCM and ASD. Check these as well.
Edit: The fuel injector driver in the PCM for that fuel injector you sparked may be smoked. These FI drivers are touchy and can be smoked even with a low impedance fuel injector.

Thanks again for all the posts! This site is great
CF Veteran
Joined: Aug 2010
Posts: 8,357
Likes: 103
From: Canton, MI
Year: 1999
Model: Cherokee
Engine: 4.0
Thread Starter
Senior Member
Joined: Nov 2013
Posts: 503
Likes: 0
From: Jax, FL
Year: 1998
Model: Cherokee
Engine: 4.0L
Sorry, long night. The fuel injector/coil rail. I said "that one" because I feel so dumb. I went to the fuses first but used the wrong tools so I thought they were fine. By dead, I meant blown.
Got really lucky that I didn't do more damage, or spend more money trying to find the problem.
Got really lucky that I didn't do more damage, or spend more money trying to find the problem.
CF Veteran
Joined: Aug 2010
Posts: 8,357
Likes: 103
From: Canton, MI
Year: 1999
Model: Cherokee
Engine: 4.0
Sorry, long night. The fuel injector/coil rail. I said "that one" because I feel so dumb. I went to the fuses first but used the wrong tools so I thought they were fine. By dead, I meant blown.
Got really lucky that I didn't do more damage, or spend more money trying to find the problem.
Got really lucky that I didn't do more damage, or spend more money trying to find the problem.
Thanks for the follow-up.
Cheers


