alpinewhite

ok guys, my 89 Laredo (4.0, auto) has been cutting out on me lately. seemingly random. ill be driving along at about 30mph or so and the engine will just shut off, no warning lights, oil level/psi is normal. the only thing that seems odd is that as soon as the engine shuts off the temp needle starts climbing quickly. if i pop the hood and let it sit for a few moments with the heat on it will usually fire right back up. little background:

312k miles
has an oil leak (rear main or pan maybe? leaked about a 1.5-2 quarts since february)
coolant is in less than stellar shape- has lots of rust in it.
tranny seems fine (dont know where to check fluid level)
not driven daily
runs fine otherwise- engine doesnt struggle, tranny shifts strong
only mod is a short ram intake.

im thinking that it may be a thermostat or something. any clues?

alpinewhite

bump for ideas... :/

BamaXJ

Check for frayed wires near the firewall. My '89 Limited did the same thing, although I'm at 160k miles. It could just be a simple wire, so thoroughly check everything and hopefully you'll find it.

alpinewhite

nothing obvious with the wires, im wondering if its just getting too hot, this only started happening as the weather got warmer around here.

JeepingDan

put some tools in that thing for the next time it does it since it's a interment problem. check for spark and signal to the injectors if none exist change the crank sensor.

alpinewhite

hmm thats getting a little advanced for me; i dont have the tools for that. a crank sensor might make sense... ill have to bring it to my mechanic if thats the case. my diagnostic ability is limited to OBD2 V6 hyundais. although i think it may be more of a cooling issue... the thing heats up quickly, almost to near the red zone, but when the fan kicks on it pulls the temp down quickly; i think the fan might not be coming on quickly enough, or coming on too often? im going to start with a coolant change/flush and go from there.

the other thing of note is that the vacuum hose attached to the vent at the top front of the engine ( seems to be a valve/crank case vent?) is only held on with a zip tie... although it doesnt seem to matter if the thing is off completely, the engine still runs.

alpinewhite

ok crank sensor is really starting to make sense. i took it out today to force it to die and sure enough, she crapped out at a stop sign, only thing was when i tried to start it, it would sputter violently, lots of banging and clunking. i let it sit for 5 minutes, and it started up fine and brought it back home.

COSXJFAN

No worries on the OBD2, you have a Renny, and they don't have them. Before you replace the CPS, try cleaning the connection at the plug, they will get crudded up sometimes. It will be near the fire wall, on the DS of the Jeep, towards the rear of the intake manifold. You can also look up from the bottom, DS of the Jeep, and see the actual sensor. It is about 2/3s of the way up the bell housing on the DS. You should be able to trace the wire from there if you can't locate it from the top. One thing to keep in mind when you change it out, is to make sure that you route it in such a way that it does not come in contact with the exhaust manifold. That will kill it quickly, and that is what made me have to replace mine. I zip tied mine to the speedo cable, and it has plenty of room there!! The DAPO didn't route the wire properly. HTH!!

CrawlnCoupe

thats what went wrong on my previous jeep. as soon as it would get up to temp, it would suddenly die and wouldnt fire until it cooled down. ended up being the crank sensor

alpinewhite

thats exactly whats happening.
ah ha, i will check it out asap. thanks for all the helpful info! do you know a good site to find replacement parts if it turns out i need a new one?

alpinewhite

quick update: brought it to my mechanic cousin and we replaced the ignition coil just out of suspicion it died while he was checking the wires around it... it was not the culprit, but i dont mind having a new coil on there, it was old as hell anyway.

the real culprit was my exxon valdez style oil leak. the oil had eaten away at the CPS harness (plus the usual corrosion at the bellhousing issue). replaced the sensor and voila! 313k and still kicking! lent it to my buddy to get to work for a few weeks while is '00 XJ was getting a new head.

so heres my next dumb question: the death shake. is there an inexpensive way to be rid of it? i dont think its the balance on the tires since it comes and goes at any speed above 50mph.

coyote121403

I have the same exact problem you did. Thanks for the info. On the death wobble there are tons of posts about it but the checklist goes: Check bushings under front, alignment, balance, change track bar, if you want to fix it temporarily for cheap throw a new steering stabilizer on it. Thats what I did till I had the money to change the track bar and it brought my DW to nothing.

alpinewhite

hey thanks for the ideas! can anyone point me in the direction of a new steering stabilizer?