Wont Start Sometimes
 

I have a 89 Cherokee with a 4.0L and automatic transmission.

Lately I have had some problems getting the vehicle to start. It will crank and crank and do nothing. I was able one time it wouldn't start to throw an old spark plug I leave in my vehicle on the coil wire and it had no spark as it cranked.

I don't know if it is getting fuel either as it has only done this while at work, trying to go to and from a meeting, and as I was running behind yesterday trying to go to work. Neither times did I have time to mess with the vehicle though I feel that it could be the neutral safety switch but I am not sure.

Like I just got home from work, yesterday I just borrowed a vehicle, put the keys in the ignition and the Jeep fired right up.

Also, once the Jeep is running it runs great with no missing or anything else like that at all.

Does anyone know what this could be?

I really need to fix this soon as it always happens when I really need it and don't have the time for it not to start.

Make sure the connector to the coil pack is fully plugged in?

Will do I was planning to check the coil wire and check and clean all the connections to the coil.

I would bet on the CPS. I have two jeeps from the 89 class and for some reason the CPS will just give up and die. I carry and extra with both jeeps and the stuff to change them out. It only takes a few mins to do the job.

Both of them have done the same thing you are talking about. You may want to unplug the CPS then plug it back in. One jeep has the updated wiring harness my daily runner does not. If it will not start, I pop the hood unplug the CPS then plug it back in and I am always off and running again. It does it at the strangest time. Overnight, drive 15 miles to work then won't start, drive for parts then won't restart until it has been unpluged.

i had the same problem with my 99, i took all the spark plugs and made sure they were the right spacing, once i did that the car fired right up. if you do that and the problem persists it will probably be the NSS

Ok I will try the CPS trick I didn't even think about the CPS.

If it will crank it is not the NSS. I was having the same problems with my 90 cherokee and now it died and will not start at all. I have been through everything on this truck, so I guess I am going to replace the CPS. The CPS isnt that old though, but I will give it a try.
Thats probably what is wrong with yours to.

Ok, I thought it would crank like crazy if it was the NSS but would have no spark. If it is the CPS can I only check if it is giving me problems starting.

Yeah, I came home from work and it fired right up like nothing was wrong. It also seems if it is the CPS it will stall or something from what I have read from other people with the same problem and mine does not do that.