unexplainable starting problems

[serenagold]

1051814

I am baffled!! I have a 1988 Jeep Cherokee Laredo with aprox. 190,000mi and a 4.0L straight 6 engine. I love this Jeep (how could you not?). However, over the past few months I've been experiencing some engine problems when attempting to start the truck. Noone I've presented this problem to has any ideas on what it might be, so now I'm here asking the Jeep enthusiests for help!!



My problem appears in two forms. 1) When I go to start the engine, the engine races to 2-3000rpms and doesn't go down. I have to shut off the engine and try to start it again. Sometimes it takes several tries before I can turn the ignition and have it start normal. 2) Sometimes I go to turn the ignition and it doesn't start at all. Oh, there's power, the battery isn't dead, the ignition works, but it won't turn over. Its like it's dead, only it isn't. Although, I will go under the hood when this happens and jiggle the wires (not that i know what any of the wires I'm jiggling do) and then, sometimes after a few tries, it will start. Could it be a coincedience? Maybe. I have no clue.

If anyone has any suggestions I would be more than happy to hear them.[addsig]

 

[judge09]

1051826

Sounds like its time for a tune-up. Replace your spark plugs and spark plug wires.[addsig]

 

[dingus]

1051843

and have your computer scanned to see if a sensor is failing. something similar happened when my crankshaft position sensor took a crap on me.[addsig]

 

[seanwheelz]

1052107

Your problems sound very similar to ones that I was/am experiencing. One of the problems, the starting issue, I figured out for me. My problem was a starter relay that had gone bad. If you track the smaller of the two wires coming off of the positive terminal, it should go to a relay box approx. 6-8 inches back from the battery. It sends a signal to the starter to engage when the key is turned. The haynes book really doesn't mention it, neither did any of my parts stores in the area. What you would need to do is take out this relay(marking the wires to there position because there should be several) and bring it to a parts store and have them match it up in their relay book. There is a slight difference, being that there is an extra plug, but the one you have should be marked and as long as all the plugs are in the exact same position, it will be ok. Now, according to most literature, the relay isn't mentioned. I don't know if this was done by a home mechanic, or just not made note of by Jeep. I've seen situations like this before so I wasn't too surprised. Where changes are made at the factory and no one is told about them. If you do have this relay in yours, it's real cheap, 7-8 bucks, and is a easy fix. As for the idle problem, mine does the same thing. Haven't figured it out yet, hope to do that this weekend. Good luck

Sean[addsig]

 

[XJeep]

1052348

Is it an automatic? If so, the "dead" issue could be a bad switch in the gear selector. Over time the contacts wear down in the "Park" position since it is used so often. It's hard to diagnose since it's so sporadic. Next time it's dead, try starting it in "Neutral". This works on my 93 XJ. I'm to much a tight wad to replace my switch. or maybe it's laziness. Good luck!![addsig]

 

[dingus]

1052363

there's an article on jeepin.com about cleaning that neutral safety switch... you don't have to replace it, apparently you can just clean the contacts.[addsig]

 

[XJeep]

1052369

Great tip Nate!! I now know what I'll be doing this weekend.



Thanks again[addsig]

 

[dingus]

1052370

here's that link...



http://www.jeepin.com/features/nss/index.asp



<TABLE BORDER=0 ALIGN=CENTER WIDTH=85%><TR><TD><font class="pn-sub">Quote:</font><HR></TD></TR><TR><TD><FONT class="pn-sub"><BLOCKQUOTE>Next you'll need to pull the NSS off the transmission. It's rather stubborn, and you can't 'twist' it off -- it's got to come straight off. Using a great tip I got from the JeepsUnlimited Cherokee forum, I threaded the retainer nut back on a couple of turns, then used a flat head screw driver to carefully pry the NSS off, using the lip of the transmission pan for leverage. This worked like a champ and didn't damage the unit.</BLOCKQUOTE></FONT></TD></TR><TR><TD><HR></TD></TR></TABLE>



this seems to be the only confusing part of the article, and i'm assuming that i'll understand it once i get it apart and look at it. i'll probably get around to doing it one of these days

...

[addsig]

 

[XJeep]

1053463

Great instructions!!! Took about 1.5 hours with no surprises. I now have reverse lights and it starts in "park!!!!!

Thanks again[addsig]

 

[Tug-n-pull]

1053466

I am not genius but but could you have an auto choke giving you a problem? Tug
:-? [addsig]

 

[MudderChuck]

1053485

Just a few other things to look at. If you turn the old key and the starter doesn´t engauge, sometimes a good wack with a solid object (on the starter), will reseat the brushes and get things going (and you´ll know it´s time for some starter service).
Many times when you get high idle, it´s the O2 sensor getting to much air. A vacumn leak somewhere. Often the intake/exhaust bolts become loose (or break), a close look and/or re-torquing might help out. Have also seen cracked exhaust manifolds, that suck air (venturi effect) instead of expelling exhaust gases, also messes with the O2 sensor and causes high idle.[addsig]