4.0 won't start (Neutral safety switch??)

Ok, my 4.0 won't start, its an 87 Renix. I had these kind of problems with it before. When I turn the key, it just clicks the starter switch relay, it dosn't engage the solinoid. This exact same problem happened about a year ago. I had the starter out of the truck, it worked fine, and nothing has hapened to it latly to lead me to belive that its cooked. Right before this happend the Jeep was coasted down a hill (about twenty feet, probably less) into my garage. It may also be the battery, which has enough volts to start the car, but I haven't had it load checked (its a 2 year old battery I got for free with another Jeep) but it has started my Jeep many times before. The last time this happened, it just worked its self out, the problem went away and it ran fine.

That does NOT sound like the NSS causing the problem.

try another battery, but also disconnect and clean the CPS wire at the back of the valve cover. Some CPS (Crankshaft Position Sensors) are known to build up corrosion inside the connector and it will show symptoms almost exactly as you described. Cleaning the contacts often resolves the sporadic, minor problems but if it persists, the CPS should be replaced.

check for damaged CPS wires as well. They often get burned through over time from engine heat.

the_bandit87 said:

The last time this happened, it just worked its self out, the problem went away and it ran fine.

Click to expand...

Maybe a semi-dry battery or poor cable connectivity to the terminals ?

Just a thought ... at times, I've experience random problems depending on the age of these components and the temps outside.

Batteries tend run dry during the hot summer months ...

Good luck.

If it were the NSS, it wouldn't click at all. If it were the CPS, it would crank normally but just not fire. I think Bchulett is on track here.

I have had this happen before to on my 92 w/240,xxx miles. It starts for me when I put it halfway between park and reverse.

xtremepyro12 said:

I have had this happen before to on my 92 w/240,xxx miles. It starts for me when I put it halfway between park and reverse.

Click to expand...

Yes, but does it click? I agree with Matthew Currie and bchulett here.

xtremepyro12 said:

I have had this happen before to on my 92 w/240,xxx miles. It starts for me when I put it halfway between park and reverse.

Click to expand...

That's the neutral saftey switch ... when it finally goes get ready to call a tow truck or a cab.

bchulett said:

That's the neutral saftey switch ... when it finally goes get ready to call a tow truck or a cab.

Click to expand...

Or keep a little piece of wire handy, with which to ground terminal 30 of the start relay. You can sneak it into the relay socket, then push the relay on over it. The other end goes to any convenient ground.

Disclaimer: Emergency only. Remember it's a neutral SAFETY switch.

Ok, I though I'd give you guys a bit more info that could help you. When you turn the key, all you get is click. Every time you turn it, it dosn't turn over, the solinoid dosn't engage, just a single click. Latly the motor has been running week, stalling once or twice after start up, and not ideling smoothly. My XJ hasn't been road worthy for almost 6 years, but for the last couple months, its been driven out of the garage about three or four times a week. The last time it was driven out, it was coasted back in. Just recently we have replaced the Fuel filter, and added more gas to the tank. I took my battery down to my other Jeep (the one the battery came with), now that one won't start either, but the battery does have enough power to work the fuel pump and crank the motor. Somthing on my good jeep is broken and stopping power from getting to the starter. I may take the starter out to make sure its not broken, but I can't think of any reason my starter would be gone, because this time last week it worked fine, and it never made a noise since the Jeep stopped running. Oh, and the fuel pump has power, it engages once I turn the key to on. I'll try the things you guys mentioned and see if it gets me any where. Thanks for the help!

Battery problem, or Grounding problem. I would definately check that you have a good strong connection to the battery, and the chassis. Go get a new battery from (Place random auto parts store name here) and try it out. If the problem is gone, keep the new battery, if it's not, return the new battery and say "It isn't quite what I wanted"


Most likely it's the battery. I had the same kind of things happen to my Durango and my Cherokee. Had enough juice to start it usually ,but rough running after start, stalling, etc. etc. etc. Replaced the battery, and it was goooood to go. Now I have a 1400CCA battery, and I could start a lot full of Freightliners.

Sorry I'm late getting back to you guys. I got my 4.0 running by putting a new - battery cable, and replacing the end on the + cable. Looking back though, I probably didn't need them. I guess the last guy who had the starter out put the + cable on a bit loose, because it had backed off and wasn't making good contact with the starter, but when I tightened it back on, it still wouldn't start. The problem was, the wire that goes from the ignition relay to the starter was on wrong. The way the clip on the wire is, it has to be on the left, if u put it on on the right, it dosn't go on right, and it eventually loosened off. After putting on the new parts and tightening the loose connections, it ran great. It still stalls on start up about once every 3rd start, but it runs much stronger. Thanks for the help with getting my engine going.

the #30 on that relay is a positive 12v...if you put that to ground you burn stuff up...