Introduction thread/intermittent breakdown - JeepForum.com
Search  
Sign Up   Today's Posts
User: Pass: Remember?
Advertise Here
Jeep Home Jeep Forum Jeep Classifieds Jeep Registry JeepSpace Jeep Reviews Jeep Gallery Jeep Clubs Jeep Groups Jeep Videos Jeep Events Jeep Articles
Go Back JeepForum.com > Models > Jeep Grand Cherokee & Commander Forums > ZJ Grand Cherokee Forum > Introduction thread/intermittent breakdown

FS: 2007-2013 Jeep Wrangler "HALO" Angel Eye KitTHE NEW! VANCO DUAL MODE 15/16″ Big Brake Kit w/BlaFS: Wranger BRIGHT License Plate LED! Just $3! Great value

Reply
Unread 07-17-2011, 07:10 AM   #1
LinBaba
Registered User
 
Join Date: Jul 2011
Location: Sacramento, CA, CA
Posts: 53
Introduction thread/intermittent breakdown

I have just acquired a 1996 Jeep Grand Cherokee Limited with 126,000 miles on it, it has the 5.2 V-8, it was literally owned by a little old lady who drove it to the store and church (friends grandmother) who bought it new

I am brand new to Jeep but recently restored a 1972 Mercedes 350SL by using a forum similar to this one, I have some -basic- mechanical skills, I can loosen and tighten nuts (a skill I learned from listening to my girlfriend, although she puts mine in a vise before she tightens them)

It has an oil leak, drips from under the oil pan and I am pretty sure 99.9999% it's the rear main oil seal, I have three different "how to" threads saved for changing that in the near future

Now my question is this, the car died while driving (for the last owner) and she had it towed home, she said it would start then only drive 10 feet and die again (didn't ask whether that was later or right then) but the impression I got was she tried again at home and the vehicle wouldn't run

the car sat for a year, since I restored the Mercedes, and her grandson, who purchased the car, was quoted a price of 1500 dollars to replace the rear main seal, he "gifted" me the car on the condition I fix it and get it up and running

OK, I put a new battery in it, it started right up, and has run fine since, I drove it around 2-3 miles, let it idle in my driveway for 20 minutes, drove it around some more, took it up to 65mph for 2 miles, I have let the engine -thoroughly- heat up, but haven't "abused it" yet, like log on some serious driving time, just little neighborhood stuff

My suspicion after reading these forums is the Crankshaft position sensor, as it seems to "fail" intermittently pretty commonly, my second "suspect" is the Powertrain module, although that is pulled outta my butt as well from reading these forums, it just seemed to be mentioned a lot in failures of this type

since hooking up the new battery, all the computer says is 0 miles to next service, would the computer inside alert me of problems or do I have to run diagnostics in a box under the hood?

Is there a way to check the CPS while it is actually functioning correctly? I saw one way to test it when the car wont start by unhooking it and voltmeter testing, but if the car is running it will read as good, hence "intermittent" failure

my question is this:

Are there any other likely suspects that would cause the car do die and then "fix itself" that are -common-, I understand I/we can't be certain of why the car died, but is it worth throwing in a new CPS (or whatever) for 75 bux and some skinned knuckles

I'd rather be pre-emptive and not get broken down by the side of the freeway, recently (2 days ago) the points in the mercedes fouled 100 miles away from home, didn't get home until 3AM, 2 months ago, my 4runner burst a rad hose on the freeway and the head blew instantaneously....also 100 miles away from home, it was a replacement for my Suzuki that had recently died 100 miles from home after many many years of faithful service, I am getting tired of this tow truck thing and driving around just waiting for my car to blow up underneath me, especially since I do commute over 100 miles a direction a few times a week, this is getting tedious

Is it worth replacing the CPS or should I drive around waiting for the boom to lower and then see what the problem is? How likely is it that the CPS is the culprit? is there any way to actually see if it is failing, or is it truly intermittent?

LinBaba is offline   Reply With Quote
Unread 07-17-2011, 07:23 AM   #2
ZeeJay1997
Registered User
1997 ZJ 
 
Join Date: Dec 2008
Location: Sweet Home, Alabama
Posts: 6,171
Check to be sure your oil leak is not at the oil filter adapter oring.

The battery could have been the only problem. Pay no attention to the VIC (the screen above the console) at this point.

Drive it and see if the check engine light (CEL) comes on or if you get stalls, skips, misses without CEL. I wouldn't start changing sensors just to be changing. You can wiggle the plugs at the PCM and everywhere else in the engine bay while it is idling to see if something is going on there.

Things you need to do - Be sure all battery connections and posts are shiny clean. Be sure the the grounds on fender by the battery and the engine block grounds are clean and tight.
ZeeJay1997 is offline   Reply With Quote
Unread 07-17-2011, 07:37 AM   #3
LinBaba
Registered User
 
Join Date: Jul 2011
Location: Sacramento, CA, CA
Posts: 53
Quote:
Originally Posted by ZeeJay1997 View Post
Check to be sure your oil leak is not at the oil filter adapter oring.
will do

Quote:
Originally Posted by ZeeJay1997 View Post
The battery could have been the only problem. Pay no attention to the VIC (the screen above the console) at this point.
would the battery dying cause it to die? as in plenty of juice to turn the engine but not enough to run it? I...haven't seen this before, would the PCM cause it to shut off or something? she could start it, go ten feet and then it would die again, I don't see that as being battery related

Quote:
Originally Posted by ZeeJay1997 View Post
Drive it and see if the check engine light (CEL) comes on or if you get stalls, skips, misses without CEL. I wouldn't start changing sensors just to be changing. You can wiggle the plugs at the PCM and everywhere else in the engine bay while it is idling to see if something is going on there.

Things you need to do - Be sure all battery connections and posts are shiny clean. Be sure the the grounds on fender by the battery and the engine block grounds are clean and tight.
will do, have been driving it around a bit, runs like a top so far, I will try and log some more miles on it today, ...I hate driving a car and just -waiting- for it to break down, I didn't trust the 4-runner (rightfully so the bastage) and -knew- the mercedes would die after sitting for ten years, something was -bound- to mess up in a 40 year old car, so driving to work propelled by a combination of butt puckers and stomach clenchings as I mutter through gritted teeth it is (Peet's coffee helps this phenomenon)
LinBaba is offline   Reply With Quote
Unread 07-17-2011, 07:45 AM   #4
ZeeJay1997
Registered User
1997 ZJ 
 
Join Date: Dec 2008
Location: Sweet Home, Alabama
Posts: 6,171
Quote:
Originally Posted by LinBaba View Post
so driving to work propelled by a combination of butt puckers and stomach clenchings as I mutter through gritted teeth it is
Lol. I carry a spare PCM with me on my daily drive to work. When you suspect a bad PCM, just be sure to carry the tools to disconnect and reconnect the battery if you need to. If that fixes it temporarily, you can bet the PCM is bad. There is something about 3 warm up - cool down cycles that causes the PCM to change modes and start acting up... sometimes. The gremlins in these things are tricky.
ZeeJay1997 is offline   Reply With Quote
Unread 07-17-2011, 07:49 AM   #5
ZeeJay1997
Registered User
1997 ZJ 
 
Join Date: Dec 2008
Location: Sweet Home, Alabama
Posts: 6,171
Quote:
Originally Posted by ZeeJay1997 View Post
Check to be sure your oil leak is not at the oil filter adapter oring.
Duh on me, you have the 318 and I don't know if it has an adapter... sorry bout that.
ZeeJay1997 is offline   Reply With Quote
Unread 07-17-2011, 07:52 AM   #6
LinBaba
Registered User
 
Join Date: Jul 2011
Location: Sacramento, CA, CA
Posts: 53
Quote:
Originally Posted by ZeeJay1997 View Post
Lol. I carry a spare PCM with me on my daily drive to work. When you suspect a bad PCM, just be sure to carry the tools to disconnect and reconnect the battery if you need to. If that fixes it temporarily, you can bet the PCM is bad. There is something about 3 warm up - cool down cycles that causes the PCM to change modes and start acting up... sometimes. The gremlins in these things are tricky.
OK, THAT might turn out to be helpful info if it saves my bacon

truth is I have -zero- idea what might be wrong, seriously, driving around and waiting for it to die seems to be the plan at the moment....
LinBaba is offline   Reply With Quote
Unread 07-17-2011, 08:28 AM   #7
ZeeJay1997
Registered User
1997 ZJ 
 
Join Date: Dec 2008
Location: Sweet Home, Alabama
Posts: 6,171
The ZJs are very picky about the battery and charging systems so the battery could have been it. There's not a problem until there is a problem. You can throw a tremendous amount of time and money away trying to fix these things because one symptom can be caused by several factors.

Just remember that a bad sensor will not always turn on the CEL, and that fuel delivery and secondary ignition are not monitored by the PCM, other than causing misfire codes. So you can have no spark and no fuel without a CEL. The idea behind this comes from EPA requirements. If it's not running, it cant pollute!
ZeeJay1997 is offline   Reply With Quote
Reply
Thread Tools


Suggested Threads





Jeep, Wrangler, Cherokee, Grand Cherokee, and other models are copyrighted and trademarked to Jeep/Chrysler Corporation. JeepForum.com is not in any way associated with Jeep or the Chrysler Corp.