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93 Jeep Cherokee won't start

The jeep is V6, auto. It ran fine every day till I let it sit for a month, now I can't get it started. Never had a starting problem. I have talked to three mechanics, and tried many things. I tried a new coil, new plugs, new distributor, new rotor, new CPS (crankshaft position sensor). I don't get it, after I put the new CPS in it started, then I shut it off, and tried to start it again, and wouldn't. I pulled it out, made sure there was a good ground, nothing, just cranks and cranks. I tried the ground thing, made sure the block had a good ground using jumper cables still nothing. I unplugged all the connectors to everything and replugged them in, tried to start it, and it started, then shut it down and it won't start again. I did the same thing, unplugging everything, and still nothing. I got yet another CPS and tried that, still nothing, so I don't think it is that. The plugs are not firing. The timing belt is fine. Those are the only two times I have gotten it to start in over 100 tries. I have plundered the newsgroups looking for advice, the two main things I tried (grounding and CPS), and all the obvious stuff. What else could it be? When it did start up, it started up instantly. I also tried starting fluid, and am pretty sure it is not the fuel pump.

Please help with advise, I hate to take it in the shop after trying all this stuff, since they will do the same stuff, or I am afraid it will work for them.

Reply to
Ray
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First, there is no such thing as a V6 in a 1993 Jeep. It is either an I-6 or a V8. The CPS seems to be the most common failure point, but you have other components to consider. If the automatic shut down relay (ASD) is not working, the engine will not start. The overall brain of the engine is the Powertrain Control Module (PCM.) If that is faulty nothing works. The PCM drives the ASD relay. The PCM takes special equipment for diagnosis. Sounds like you should take it to a Jeep dealer, not an independent.

Dick

Reply to
Dick

Before Mike R. say's it.. have you checked the ground wire from the engine block to the fire wall?? if that cable is shot it will cause similar symptoms. To check this, run a jumper cable from the negative terminal on the battery to the engine block, if jeep starts then that the problem.

Snow...

Reply to
Snow

I think he has covered that issue according to the OP.

: > >started, then I shut it off, and tried to start it again, and : > >wouldn't. I pulled it out, made sure there was a good ground, nothing, : > >just cranks and cranks. I tried the ground thing, made sure the block : > >had a good ground using jumper cables still nothing. I unplugged all

Another notable item prone to failure is the neutral safety switch.

-Brian

Reply to
Cherokee-LTD

You say "the plugs are not firing" ... do you mean no spark? And if that was just a typo, maybe rethink the fuel pump ... mine intermittently failed a few times untill it finally failed for good with the symptoms exactly as you have described.

Reply to
bowgus

Please READ my post, as I stated in my post that one of the things I tried was checking the ground wire and running a jumper from the block to the battery. I also changed the CPS twice.

Ok, new info, I got the computer codes, and I had 12, 54, and 55. So it seems like 54 is probably my problem. Is there a way to reset the codes so I can make sure I get the same code. Would the Hall effect sensor under the rotor cause this? I am going to pick this part up tomorrow and try this. I did play with all the relays, swapping the positions with the starer, and checked the fuses, so I am pretty sure is is not a fuse or relay like the ASD.

Yes the PCM could be gone, but why would it have started those two times? Well thanks for you help so far, I will keep looking.

Reply to
Ray

I would yank a pcm from a wrecking yard to test it. It sounds like you have spent plenty on it already! KH

Reply to
Kevin in San Diego

Can't resist, neither one of you two can read... ;-)

The ground that 'can' cause those symptoms is the mesh one from the engine block to the firewall. If that goes ratty, the PCM doesn't turn on.

I would run the jumper cable from the battery to the firewall to check that.

Other than that, maybe the pickup in the distributor, but usually when I see those go, they are just plain gone.

I have also seen the hold down foot on the distributor get rusty and not connect the distributor to ground.

Mike

86/00 CJ7 Laredo, 33x9.5 BFG Muds, 'glass nose to tail in '00 88 Cherokee 235 BFG AT's

Ray wrote:

Reply to
Mike Romain

Yeah could be a fuel delivery problem, what kind of pressure are you getting? And what was that about plugs not firing?

Reply to
Greg Ladigin

Don't know if you're following this thread still but...

I have a 1990 Cherokee LTD 4 L I had the exact same problem. We tried relays plugs, wires, cap, rotor, coil, crank sensor, and ballast resistor for the fuel pump. We had fuel pressure. It turned out to be the computer, or rather the computer connector ( yes I bought another computer to find out the hard way ) Mine's mounted beside the steering column under the dash. I grabbed the connector and gave it a good push and it started right up. Seems like one (?) of the wires in the connectors wasn't all the way in and the computer was loose on the bracket. I haven't had a problem since. It's been about a year. Hope this help.

Jeremy

Ray wrote:

Reply to
riceman

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