00silver Posted December 20, 2013 Share Posted December 20, 2013 OK, I'm new to CC, but not jeeps so I have a working knowledge of TJs XJs Zjs & other models, but not so much on an MJ & older xjs(pre 90). I bought my first one last week, and it's got some issues to say the least. I've searched naxja quite a bit, but the MJ section is limited, so here goes. I have a 1988 long bed lerado with 4.0 & aw4 auto & 4x4 (rust free). I have no interior lights or stop/ brake lights. I have checked at the fuses & replaced any that were blown, so that's out of the way. The turn signals half way work when the emergency flashers button is pulled out (I have no idea why). It seems as though some one at some point had amps & speakers in the truck due to the rats nest running from the fuse panel to the rear of the seat. I fear that's where most of my problem is. Next is the idler pulley, the belt routing on this 4.0 is different than any 4.0 i remember so maybe I'm missing something with older models. it has factory A/C so the idler pulley sits between the A/C clutch & top of thermostat housing. I can't get this thing to stop screaming. I have replaced the water pump, idler puller(twice), belt, and checked all the other pulleys & they turn smooth. The belt is not to tight or lose. If I spray PB blast on the back side of the ilder pulley it shuts up for a minute & then right back at it. Anything advice would be helpful. Thanks again. Link to comment Share on other sites More sharing options...
yxmj Posted December 20, 2013 Share Posted December 20, 2013 With the lights the first thing I would check is make sure all your grounds are good (look on here there is a post from a guy who is very knowledgeable on how to check and refresh the grounds) The pulley is a puzzler....since you say you changed it.....because with the way you describe it (quite when oiled then back to squealing) it sounds like a fried bearing.....but :dunno: Link to comment Share on other sites More sharing options...
00silver Posted December 20, 2013 Author Share Posted December 20, 2013 Thanks YXMJ. I did buy the cheaper belt, could it be the cheaper belts don't hold up as well, or stretch. I know the routing is different on the older 4.0's than the newer ones. Link to comment Share on other sites More sharing options...
yxmj Posted December 20, 2013 Share Posted December 20, 2013 What year is yours....Pre-90 with air ....Try this drawing....http://www.cherokeeforum.com/f2/4-0-belt-routing-140267/ The top idler in the pic would be your air Link to comment Share on other sites More sharing options...
sloride Posted December 20, 2013 Share Posted December 20, 2013 ^^^^agree Use a screw driver or ratchet extension for a stethoscope, put one end to the suspect part squeaking and the other end to your ear. This way you know for sure. Maybe more than one thing is squeaking on you. I've seen it before. As for the wiring? Good luck there. Find a good copy of the wiring diagram for your truck and start investigating what belongs and what doesn't. Link to comment Share on other sites More sharing options...
00silver Posted December 20, 2013 Author Share Posted December 20, 2013 Thanks sloride, but already tried that. I'm sure it's the idler, just not sure whats causing it. I think I'm going to exchange the belt for the more expensive one. it's the only weak link here. It can't be the pulley, I've replaced it twice & checked all the other ones. Link to comment Share on other sites More sharing options...
cruiser54 Posted December 20, 2013 Share Posted December 20, 2013 Thanks sloride, but already tried that. I'm sure it's the idler, just not sure whats causing it. I think I'm going to exchange the belt for the more expensive one. it's the only weak link here. It can't be the pulley, I've replaced it twice & checked all the other ones. Loosen the belt and spin the idler by hand. It should be smooth, not lumpy or catchy. If it is, you can replace just the bearing. As for the lights, I would do a complete ground refreshing, as can be found in the link in my signature, along with the connector refreshing. Also address the C101 connector which is also in the link. Please report back. Link to comment Share on other sites More sharing options...
87MJTIM Posted December 21, 2013 Share Posted December 21, 2013 Welcome to the addiction. Here is a link to the 88 wiring. Download it to your computer and refer to it often. http://comancheclub.com/topic/12083-electrical-manual/ As for the squeal, check the harmonic balancer. Mine had a nasty squeal. I tried all the same things you have tried. My mechanic diagnosed the HB and replaced it. Squeal gone. Good luck. Link to comment Share on other sites More sharing options...
HOrnbrod Posted December 21, 2013 Share Posted December 21, 2013 If the noise turns out to be the idler pulley bearing (it often is), the replacement bearing number is 6203-2RS. They are everywhere online and easy to replace. Cost about $2-$3 each. Link to comment Share on other sites More sharing options...
Jeep Driver Posted December 21, 2013 Share Posted December 21, 2013 Welcome to the addiction. Here is a link to the 88 wiring. Download it to your computer and refer to it often. http://comancheclub.com/topic/12083-electrical-manual/ As for the squeal, check the harmonic balancer. Mine had a nasty squeal. I tried all the same things you have tried. My mechanic diagnosed the HB and replaced it. Squeal gone. Good luck. Yep, happened to me too. Link to comment Share on other sites More sharing options...
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