1996 Jeep Grand Cherokee Laredo - ticking/clicking sound - shaking

Home  \  Repairs & Maintenance  \  1996 Jeep Grand Cherokee Laredo - ticking/clicking sound - shaking

Hello everyone...My name is Jeff and I am, unfortunately, vehicle-maintenance impaired.

OK, I have a 1996 Jeep Grand Cherokee Laredo, V8. 101,000 miles on it.

Problem Description:
About a week ago, I noticed a very subtle shaking to the car as I was driving on the highway (I drive an hour to and an hour back from work). We have been having some bad weather (windy) of late, so I thought it was just the wind shaking the car or, because I only noticed it on the highway, I thought it was just the roads on the turnpike might be lumpy.

This morning, as I got off the highway, and closer to work, the shaking was very noticeable and the engine light came on.

On break I checked oil, transmission, and coolant fluids. All were fine.

As I had the hood up and the engine on (for checking the transmission fluid) I heard a clicking/ticking sound (like what you might hear from an electrical shock).

Looking around, I noticed a spark coming from a wire that connects to, what I think is a spark plug (but it was not located with the other spark plugs, more to the front, but with the same kind of wire). The spark was going from that wire to the compartment that holds the oil.

After checking the internet, I found a couple places that state that it could be that the wire is bad and the electrical charge is going to ground.

I then went out and checked the wire, and sure enough, it seemed distorted and there was a crack in it. So, I moved it away from the oil compartment and started the car. I didn't notice the spark anymore, but I still heard a ticking/clicking sound (no noticeable pattern).

Checking the internet again, a couple places mentioned valves.

Checking my manual, it says the engine light coming on means an emission problem.

So, my questions are as follows:

1) Would a clicking/ticking noise be related to an emission problem?

2) Could the engine light be coming on for another reason? (possibly letting me know that the engine isn't getting enough power because the insulation wire is going bad)

3) Could the wire problem for a sparkplug cause the engine/car to shake and the check engine light to come on?

4) From what I have described, does anyone have an idea of what else it might be?

5) My commute is an hour away....will it be safe to drive it home tonight, or I am out of luck?

Thanks SOOOO much in advance for any help anyone can offer me!

posted by  jeffcravener

1) You have the 5.2Litre Chrsyler 318 Cubic Inch V-8 in that truck and the computer system is running on an OBD II interface. You probably were seeing arching from the "plug" wire that connects the distributor to the coil in the engine. This also explains the ticking sound. Ignition coil output in an automobile is between about 40-60 thousand volts so if it is arching, you're gonna hear it. Here's a simple explaination: The coil powers the distributor such that when the rotor spins around inside, it makes a contact to each plug wire at a specific time thus firing that cylinder. This is called engine timing. If that coil to distributor wire was loose, frayed or degraded, your engine could be experiencing a loss of power, intermittent power interruption based on jarring from bumps, etc. Due to this, I hypothesize that the check engine light is on due to something such as a "multiple cylinder misfire" code detected by the coil or pickup in the distributor and sent to the pcm. I think it was 1998 that Chrysler starting installing direct ignition on these vehicles including the ones that have the 4.0 litre I-6. This system eliminated the distributor and changes completely over to a coil pack over each spark plug. Direct Ignition.
** You need to have the computer scanned for DTC's and tell us where they are. If that MIL is on, there is a reason and the computer scan will tell us. That is the first thing to do.
Also if you have a cylinder missing due to this, YES the O2's could be picking up raw emissions in the exhaust gasses and throwing the check engine light too as sort of a secondary effect scenario whereas the coil to distributor connection being loose or worn or arching.

2)I've addressed this above :mrgreen:

3)The answer is yes. The car shaking is probably due to the engine not running on all 8 cylinders and you are running unbalanced. The light will come on possibly for one of the reasons that I have highlighted above.

4)Without seeing it and from what you've told us, I think that I am pretty close to the problem. Any other thoughts???

5)Check these things before leaving work. Open the hood and make sure that the wire running from the coil to the distributor is tightly snapped in place at the coil end and at the distributor end. Make sure the ticking is gone and that the engine idles and acelerates smoothly and that there is no slight vibration from a misfire. If there is not, drive it and see if the vibration is gone and that you have plenty of power.

6) Report back :thumbs:

posted by  cmeseadoin

Thanks for taking the amount of time you did to explain it.

OK, on lunch I went and inspected the wire as much as I could, there were three splits in it, so I bought some electrical tape (I am doubting now if it will be enough, with as many volts as you said that wire takes) and wrapped it around the wire where the splits were.

The ticking/clicking stopped, and I didn't see any more arcing. I drove it around as much as I could (with the lunch time limit) and i didn't notice any shimming/shaking. However, the check engine light was still on.

I am going to print out what you mentioned and give it to my mechanic tonight (well, as long as I make it home).

Someone here at work mentioned that it could be oil leaking into the engine, causing a problem with the valves?

From what you said, and what else I have been able to find on the web seems to point to that bad wire.

posted by  jeffcravener

You're welcome!! :thumbs: I think you need to discredit anything the person told you about the valves, LOL. You've said NOTHING here that would lead me in the direction that your engine is having a problem mechanically and it sounds like that person either is car illiterate or seriously misinformed as to what the problem is. You need to explore that wire and replace it. Now that it is not arching, drive it home and see how she does. If all is well then problem solved. You will have to have the check engine light cleared at the shop. They will hook up the computer, scan it and determine the codes (I bet it points to what I previously explained) and then clear it out. I think you've got a very simple issue going on and it sounds like you're on the right track...at least from all I can do online....Good luck, let me know! :thumbs:

posted by  cmeseadoin

Cmessadoin- I'll bet he will find a P0300 series random or specific cylinder misfire

If you find that is true, go ahead and clear them since you probably fixed the problem when you replaced the bad plug wires

Some auto parts places can read the generic OBDII codes and clear codes and will do it at little or no charge

posted by  tbaxleyjr

Well, when I got home I inspected the wiring more carefully, and sure enough, 6 of the wires had cracks in the coatings.

I ran to autozone and replaced all the wires (my first 'working on a car'). IT was surprisingly EASY...I would have been very mad had I paid someone to do that, and then found out how easy it is to do after.

When I started it up, the check engine light DIDN'T come on! I was so happy.

So, I guess that they sometimes reset themselves?

Driving to work was great. Itm ust have been like that for quite awhile. I had forgotten how powerful a V8 is supposed to be!!

Also, for the last couple months, my sub woofer had been 'thumping' sporatically. It idn't do it at all today. I guess there was some kind of feedback from the arcing going o the sub?

Thanks again for the help everyone! What I thought was a car replacing problem, turned out to be a simple fix. thank god for the internet!!!

posted by  jeffcravener

Yep, you nailed it......plug wires are SIMPLE and yes, I would never pay someone either. You were simply dealing with a worn out wire-set......Yes the sub was receiving electrical impedence feedback from the fact that your coil was arching to the engine thus to the frame and sensitive electronics like radios and amps will pick that up, especially when it is many volts such as from a coil. You learn something everyday don't ya. :hi:

So let me ask you......have you checked those valves out yet to make sure they are ok.....might wanna pull the engine down like that co-worker suggested :laughing: :laughing: I'm JUST kidding! ;-) Enjoy a smooth V8!! :thumbs:

posted by  cmeseadoin

Oh and I forgot.....yes the check engine light is probably off because the vehicle has been driven enough "good trips" to cause the computer to no longer see the error condition so it has de-illuminated the MIL on the dash. I am sure there probably is a history code in the PCM though but if the light is off, you're fine. The pcm reads errors by determining "good trips." In simple terms, if the computer experiences a problem from one of the systems it sends a red flag up called a pending code. That pending code is remembered and then the vehicle runs itself through was is call a "trip." If that trip or set of trips commonly called cycles, depending on how the system is made to function by the design engineers of that auto manufacturer, comes back clean, the pending code is forgotten and erased from memory. If the vehicles still sees an error or fault, it is called a bad cycle or bad trip and it says to itself, hmmm better alert the driver and therefore the MIL is close-circuited to illuminate. Now, all this and how it works is very complex but the basics have been explained. Some vehicles requier X amount of cycles before it will set a code.....others set a code when it sees something bad happen. Some Check engine lights will come on and if the problem goes away they will still stay on for longer as the metrics that are used are more intense to make sure that the problem is no longer there before it will shut off the light. All cars are a little different but that is what happened here. You eliminated the problem, a hard code was not set in the pcm, so when it cleared and the pcm saw that, it said BYE to the light and shut it off! :-) Enjoy :thumbs:

posted by  cmeseadoin

pretty good explanation

posted by  tbaxleyjr

Your Message