'96 Jeep Cherokee sport won't start

rapunzel · #1 01-31-2007, 07:57 AM

The above vehicle left me stranded for about two hours before my husband could rescue me. We replaced the battery and all was well...for a week. My husband then replaced the alternator, pick up head and coil- the engine would turn over, but no spark. I did some on-line research and,thanks to your forum, discovered that the problem was the crank sensor. All was well when my husband replaced that...for 2 weeks. Now, it is back to not starting, acts like the battery is dead, will start with difficulty after being on the battery charger. My husband had to rescue me again last night and I am sure tired of being the damsel in distress; I don't think he's real happy about it either since it was about 20 degrees outside. Pleeease help!
Rapunzel

fredjacksonsan · #2 01-31-2007, 08:26 AM

I'd suspect the battery cables are corroded; check them, if corroded then replace.

rapunzel · #3 01-31-2007, 09:39 AM

I realized after I had put this in this am that I had omitted some vital info. My husband repalced the bateery cables with the alternator, etc.
The alternator gauge reads that is charging at slightly less than 14, unless I have the blower motor set on high. Then it reads about halfway between 14 and the lowe red zone. Any ideas?

fredjacksonsan · #4 01-31-2007, 09:45 AM

I'm not the electronics guy (he'll be along shortly I think) but if the fan on high is dropping your voltage by that much, it would indicate the problem is there. I'd think that at that level, it's slowly draining your battery.

Try this as a temporary fix: when it's running, get the fan switch to a speed at which the voltage stays near to 14. It should keep running.

rapunzel · #5 01-31-2007, 10:18 AM

Thank you for your reply fredjacksonsan. I have tried decreasing the fan to low once the interior is warm, it doesn't seem to make a whole lot of difference. I am very frustrated, I know my husband is, too. Any suggestions would be appreciated.

fredjacksonsan · #6 01-31-2007, 10:46 AM

Welcome. Like I said though, I'm not the electronics guy so wouldn't know where to start.

I know it's cold out, but running it without the heat on will likely let the battery stay charged until it can be figured out.

rapunzel · #7 01-31-2007, 11:34 AM

Could it be a starter? My husband thought maybe a cylanoid was bad on the starter, causing it to only turn over after the battery had been on the charger due to higher amperage.

fredjacksonsan · #8 01-31-2007, 11:36 AM

I'd think that if it's the starter you wouldn't have had it running fine for a week. To me at least, it points to a slow drawdown on the battery from the fan switch.

rapunzel · #9 01-31-2007, 12:11 PM

OK, I was talking with my husband. He pointed out that although the engine would not turnover, the other electrical components (headlights, radio, etc.) were fine. I have also noticed that the shifter indicators do not line up correctly. In addition to this, I have to hit the button on the shifter a couple of times after putting it into park to extract the keys from the ignition. Could the neutral/safety switch cause this? If so, why would the crazy thing start after being on the charger?

fredjacksonsan · #10 01-31-2007, 01:09 PM

The NSS could be an issue, but I'd be more concerned with the fact you have to push the button on the shifter to get the keys out. THAT would cause the starter to not engage - if the shifter isn't all the way in park.

I had an older car that you had to hold in park in order to get it to start.

rapunzel · #11 01-31-2007, 01:17 PM

I tried that-I even took it out of park and put it back in (more than once and no I did not slam it into park-but I thought about it!)). I just don't understand why the battery charger would make a difference. My husband is not convinced that is the problem, either.I did persuade my husband to take it to the parts store where we purchased the alternator. They said they can check both the alternator and the starter. Maybe we got a bad alternator(rebuilt with life time warranty). Who knows. I guess we'll go from there. In the mean time, I look forward to any input and will let you know what they found. My husband is usually pretty good at this stuff, but we have never owned a jeep before. Future ownership is looking rather bleak at this point.

rapunzel · #12 01-31-2007, 06:02 PM

Well, the parts people said that the alternator is producing the correct amount of amperage. The problem is the regilator is not telling the alternator to kick it up a notch when the blower motor is on high, the headlights and wipers are on. OK-makes sense. Unfortunately, in this particular model the amperage output is externally regulated by a computer. So for a nifty $280(plus $70 core) hopefully this will be fixed. The part is supposed to be in tomorrow AM. Can anyone tell me where to find this part on the engine?

fredjacksonsan · #13 01-31-2007, 08:37 PM

Sounds good, hopefully that will be the fix.

fredjacksonsan · #14 01-31-2007, 08:57 PM

...and hang in there. These are good vehicles, just have some odd issues once and awhile.

QuietErp · #15 02-03-2007, 04:43 PM

I have been having the same problem recently. I started by replacing the battery, checking cables, alternator etc.. I assumed I had a short in the truck but after measuring milliamps when the truck was off that was not the culprit. The one effective method has been slamming the drive selector into park. I thought this was silly but after seeing this post i'm not so sure and I will explore the NSS theory.

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