Jeep Cherokee Grand Cherokee Engine and Performance Problems

jmousseau44jmousseau44 Member Posts: 3
Hi, I'm new here and looking for some advice on my Jeep Cherokee Sport. I'm not very mechanically inclined so please try and bear with me.

I recently took my jeep in because the engine began vibrating really bad during cold starts (in the morning) and after hot starts (?) after it had been running for over a half an hour, turned off then started again within say 15 minutes. When it would begin to vibrate the jeep would almost appear to be on the verge of stalling but never did. I ended up taking it in to a dealer and after looking at it determined it was the timing belt (mechanic told me it was set ten degrees ahead) and reset it. At first everything seemed fine but after 3 weeks now the vibrating seems to be returning (but no way near as bad as it was before). I'm also noticing that fan seems to be always running (though the heat gauge never goes over half) and what sounds like a pump (water pump maybe?) constantly working. I'm looking for some opinions on what could be going on before I take it back in again. My jeep has about 115,000 miles on it and I've been good about the maintenance. Like I said earlier I'm not really mechanically inclined so I apologize in advance if this seems to not make sense. Any advice is greatly appreciated.



  • charlene2charlene2 Member Posts: 1
    My daughter has a 92 Jeep Cherokee in which she was told the engine contol module was bad. I bought a manual for the jeep, but there is no information about the module. Can anyone tell me where the module is, what it looks like, where to get one and how to replace it?
  • mullins87mullins87 Member Posts: 959
    The ECM is located under the hood. I don't have an older Cherokee, but on my '01 it is located in the driver side front corner near the air cleaner. The ECM on my '95 Wrangler is located, still under the hood, on the drivers side rear corner near the brake booster.

    The ECM will be a black box approximately 6" tall by 8" long and will have a large wiring harness connected to it. The harness should be fairly easy to trace. I don't know how you can check yours without having another Jeep you could try it on.

    You should be able to go to ebay and find some. Be sure to check with a professional first, but I'm thinking you can use any year ECM from '92 to '95, just so long as the engine and transmission are correct.
  • mullins87mullins87 Member Posts: 959
    I just did a quick search for you on ebay by typing in "jeep computer". BTW: I am in no way connected to this auction.

    link title

    I'm not telling you to buy this one. I only provided this link as an example of what you might look for.
  • mullins87mullins87 Member Posts: 959
    Well? How'd it turn out?
  • gardmangardman Member Posts: 1
    i just replaced my 94 cherokee's 4.0 engine with a new rebuilt engine by hesco. new plugs, wires, rotor, dist cap, gaskets etc. the engine runs great at speed but exhibits a very rough idle. i've replaced the cam sensor, the o2 sensor, and cleaned the throttle body and idle air control. no improvement at all. any ideas
  • mullins87mullins87 Member Posts: 959
    Have you ruled out a vacuum leak? The timing could be set too high.
  • howie56howie56 Member Posts: 21
    I have a new 2005 grand cherokee w/ the 5.7 hemi and 4400 miles on it and within the last month the engine is starting to surge when not under load and the dealer says chrysler said this normal - - Ya Right - - - I t surges up to 200 RPM's when going 68 miles an hour and with cruise on - - anybody else having this problem ??? This is very dangerous . . . . .
  • tidestertidester Member Posts: 10,059
    You may want to try the main Jeep Grand Cherokee: Problems & Solutions discussion.

    tidester, host
  • jlando22jlando22 Member Posts: 1
    Hello maybe someone on here can help me , I currently own a 1998 Jeep GC 5.9L V8 limited delux and it is overheating and cant seem to fix it i tried the thermostat so we were thinking that it could be the water pump or somthing but i came to find out that the fan is not turning on can someone tell me what is wrong with that please and thank you !!

  • pliskinpliskin Member Posts: 5
    I have a 2001 Jeep Grand Cherokee 4.0L
    I noticed the temp. gauge was in the red and the overflow bottle was filling up.I checked all the fuses and they are good. I turned the heat on to get rid of the prob.; but I noticed that the radiator fan is not coming on at all. What should I check for or do ???
  • ancjeepancjeep Member Posts: 6
    your problem could either be the cooling fan relay which is
    located under the front bumper cover on the passenger side,
    or it is the cooling fan itself. both parts are known problems.
  • spurlockspurlock Member Posts: 1
    Two falls ago my 95 Jeep Grand Cherokee V8 had a cracked radiator no problem i replaced the radiator. Later that May 2005 i had an overheating problem, the radiator fluid would get hot and boil over more or less through the reservoir tank (sound familiar jeep owners>?) So i replaced the thermostat (keep in mind this is with no AC running at all) i had to replace the hoses, i replaced the water pump. The fan and belts work properly. Now when the weather is 75degrees F and under on the highway cruising at 75mph no problem. Any hotter then that, Jeep overheats!
    In my opinion as a jeep owner, a 1 owner none the less where is this problem coming from. i have around 135k mi and have done all the basic maintenance required.

    Did this raditor shop put in a raidiator for a v6? i never had problems like this before that factory radiator went out, or is it a Bad Jeep design flaw because that grill shure is small to house any type of air flow for a v8 comapred to a like a v8 housing on a truck? hmmm Hopefully we will all find the answer to our needs? (should i install an electric fan) PLEASE HELP US!
  • roger44roger44 Member Posts: 4
    My battery is being drained while setting in driveway. I unhook the negative terminal, hook voltmeter between post and battery cable and get reading of 5 volts. I pull the 30amp engine control fuse and voltage goes to zero. Is this normal? Is problem in ECM box or in the circut? Whats recommended action? Any help appreciated.
  • mullins87mullins87 Member Posts: 959
    Is that the only fuse that causes the tester to go to zero? I would try all the fuses next to see if I could isolate it better.
  • roger44roger44 Member Posts: 4
    I have pulled every single fuse...under the hood and under the dash. When I first hooked up the volt meter between the negative cable and the post, the meter read 8 volts drop. I pulled the dome light fuse under the dash and the voltage then read 5 volts. I pulled the 30 anp engine control fuse under the hood and voltage went to zero.There is no fuse under the dash that goes to the ECM that I can see. I reversed the process and same results. I have done my best to look at the wireing going to the ECM but that is almost impossible without stripping the harness covers. I appreciate your help. My question is: can something go wrong inside the ECM that would cause this reaction? Whats the chances of finding a good ECM at a junk yard? Worth a try if the cost is right?
  • mullins87mullins87 Member Posts: 959
    Well, it's possible the ECM is not turning off the power to one or more sensors eventhough the key is switched off. ECM's for your '92 should be pretty darn cheap.
  • mullins87mullins87 Member Posts: 959
    You can use an ECM from a '91 to a '95, I'm pretty sure. I know you can use a '92 to '95. Just make sure it's the same configuration as the Jeep, 2wd vs. 4wd, auto tranny vs. manual. Do a search on ebay for a Jeep 4.0 computer or ECM. Here's one I found:

    link title
  • longfellowlongfellow Member Posts: 8
    Just a thought and a question.
    Did you put this radiator in during cooler season months and then later when warmer weather came along with it came overheating problems?
    If this is correct' than radiator installed may not be
    correct radiator for v8 needs to keep car cool.
    Recheck radiator size or radiator part number to see if this is the correct radiator. Also if it is' then completely flush cooling system so it,s cleaned out. Could be a flow restriction somewhere. All I could think of.
  • gghostgghost Member Posts: 4
    Have had recent intermittent problem with Jeep Overheating am getting the following diagnostic codes 0031, 0051, and 00136
  • nateffnateff Member Posts: 1
    I had the same problem just about a month ago. If I sat to long with the engine running it would overheat, once I stated moving again it would cool itself down. The problem was that the cooling fan relay was faulty. Have a diagnostic test preformed on the cooling fan. Replacement part cost $195.00 for Jeep dealer.
  • jeff12851jeff12851 Member Posts: 1
    I have a 92 Jeep Cherokee with 275K miles that I have owned since it was new. It runs great, but recently it has totally cut off 2 times while driving, the 1st time I was able to restart in neutrall in traffic, the 2nd it would not restart and had to be towed. The dealer had it for a week and got no spark the first day. Day two of tests, it started imediately as if nothing were wrong and they could not get it to stall again. I got it back, drove out to eat, as I was attempting to shift into reverse to leave the parking lot, it stalled dead again. It would not restart in park; I shifted into neutrall after a few minites and it started imediately and drove fine home. Could this be the neutrall safety switch going bad on the transmission?
  • joshtayljoshtayl Member Posts: 1
    I have an ’89 Cherokee and I’m experiencing a similar problem. It starts fine and runs fine for about 15-30 minutes then starts “cutting out,” similar to the engine being turn off and then immediately back on. As long as I keep the RPMs up (1 foot on the brake and 1 on the gas), it doesn’t die (but still cuts out). But, if I let the RPMs dip below 1K (stopping at a light), it will die and not restart. I usually have to let it set for about 1 to 2 hours before it will start again. I’ve replaced the rotor, distributor cap, and spark plug wires, then the ignition coil, and finally the fuel pump and still have the same problem. Have you had any luck fixing your Cherokee? If so, how did you fix your problem?
  • gauthiergauthier Member Posts: 1
    I have started having this same problem . I re-did my entire cooling system and my Jeep still gets hot 210 so far. I am going to run without a thermostat , flush the system again , and try some " Royal Purple " and wait and see what happens .
    I had this problem once before with a Thunderbird in the early 80's . This problem seems to occur after 100k .
    I never could solve the problem on the Tbird , it just kept getting worse . PS both vehicles were purchased new and were well maintained .
    If any body has a solution P L E A S E let me know .
  • lildavidjaxlildavidjax Member Posts: 68
    crankshaft position sensor, see post 2103.Mine never threw a code.(check engine light)
  • jcampionjcampion Member Posts: 3
    I have a 99 Jeep Grand Cherokee Laredo which I inherited from my son. My son replaced the water pump once before giving it to me. I have had to replacae the water pump twice. Both times I was told the water pump needed to be replaced when the "low coolant" light came on. Now the low coolant light is coming on again. It seems like every two years we have been replacing the water pump. Could there be something else causing the low coolant light to come on. Even when we refilled the coolant it still comes on. Any suggestions.
  • mullins87mullins87 Member Posts: 959
    "Both times I was told the water pump needed to be replaced when the "low coolant" light came on."

    I've never heard this. However, when a water pump goes out, many times it will start leaking coolant and will cause the light to come on. Just because the light comes on, doesn't mean the pump is bad. You could have a leak elsewhere. Have your mechanic pressure test the cooling system. If the leak isn't obvious and the pressure gauge is going down, then check the heater core and engine oil. If it's the heater core, you'll smell the anti-freeze inside the Jeep. If it's the head gasket, then coolant will leak into the engine oil and will turn it into a sludge resembling chocolate milk.

    How many miles are on this Jeep? Three water pumps sounds like too many.
  • biz87biz87 Member Posts: 1
    My 1993 jeep grand cherokee has been having problems with the oil pressure gage for about 6months it doesnt seem to be causing any problems with my jeep. But latly since its gotton below 70 most days its gone from just having high oil pressure to randomly up and down. It doesnt seem to matter if im on the gas or off it. any ideas.
  • bluesun99bluesun99 Member Posts: 16
    I had a similar problem on my 2002 GC Limited. A slow but continual loss of coolant. It wasn't a water pump problem. I have the split system for heating and cooling. Drivers side would warm up okay but the passenger stayed cold. A test revealed that the passenger heater core had a slow leak. I never smelled fluid nor did the carpet get wet. Core replacement fixed the problem. Just glad I bought the extended warranty. Have the dealer pressure test the system.
  • jeeps2jeeps2 Member Posts: 45
    I'm back, Need some help from the experts on here. Trickster, you still around? Yesterday leaving work, stopped at a light and my check gage alarm went off. Noticed the oil pressure dropped to 0psi. No tapping, just no pressure recorded. As I began to take off, the pressure went to around 40psi. Stopped again and same thing, no pressure. Thought it might be the sending unit. R/R the old switch, and now the pressure goes to between 30&40 psi under a load, and down to 20 at idle. Is this a good pressure for a 4.0 96 JGC? Thanks for any help. :)
  • jcampionjcampion Member Posts: 3
    Thanks for your email. I will definetly keep that in mind, because coincidently just this morning, I went to start the car and also turned on the heater (low) and it made a popping sound and then the check engine light came on and stayed on. I was able to drive it but it drove rough and jumpy. I will have to check it out later today. If you have any suggestions I would appreciate them.
  • navigator30navigator30 Member Posts: 2
    My oil pressure dropped to zero on my 2001 Jeep Grand Cherokee Laredo, but didn't seem to cause any problems and actual oil pressure was good. The dealer said the oil pressure sending unit was leaking and causing impedence. It was replaced.
    Nine months later, the oil pressure gauge drops to zero when the engine gets hot and the RPM goes low when pulling up to a stop sign. Comes back to normal at highway speeds. Now the dealer is saying the "pig-tail" connecting the sending unit to the gauge is leaking and causing erroneous readings.
  • purceld2purceld2 Member Posts: 1
    I seem to have the same problem with a 97 Model

    Lossing coolant, funny smell, running rough, how much is a heater core?


  • navigator30navigator30 Member Posts: 2
    The oil on the "pig-tail" to the oil pressure sending unit apparently came from the oil filter which had not been properly tightened. This can happen when the oil change technician doesn't properly snug the filter when changing.
  • ddowie0206ddowie0206 Member Posts: 1

    I am experiencing the same problem on a 2000 GCL. Have you gotten any results to fixing your problem?

  • charleytampacharleytampa Member Posts: 43
    I just changed the oil on my 1993 4.0 Cherokee. Put in mobil 1 the oil pressure gauge is at zero. No problems with the engine, but I do not wish to drive it! Engine is actually much smoother since the oil change, but hte needle is on zero psi. ANy thoughts? Perhaps I busted the gauge on accident when replacing the filter? thanks

  • jeeps2jeeps2 Member Posts: 45
    I would suggest that you check your connection at the sending unit first. It is located at the bottom of the distributor. If that is plugged in, then I would replace the oil sending unit. Just unplug the unit and unscrew off. Check to see if it is a 1 or 2 connector unit. The 4.0 calls for either one in the book, so you will have to match it up. My guess is , it will be the 2 prong. Easy fix, and cost around 30-35.00 to replace. good luck
  • jeeperz1jeeperz1 Member Posts: 1
    Last year I replaced the entire dual-range heater controls due to a fan switch being inoperable to the tune of $700.00 at the dealer. The switch is fine, now I don't have any heat. I just replaced the thermostat and topped off the coolant and still no heat. I have heard it could be a "stuck" flap or director in the heater assembly. Any help will greatly appreciated. Thanks.
  • bostonstevebostonsteve Member Posts: 3
    Hmmmmm. I was under the impression that the 00 sport had a timing chain (not belt) and didn't need replacing.
  • jmousseau44jmousseau44 Member Posts: 3
    That is strange but that's what the dealer said, "the timing belt was set ahead."

    And it is a 2000 Cherokee Sport 4D/4WD 6cyl.

    So far it's been running ok but with winter coming I'm a little concerned. I keep up the maintenance on it but you never know.

  • jeepachejeepache Member Posts: 8
    Ok here goes I have a 1987 jeep cherokoee with straight 6 Biggest problem is that it will run but has no power(wont even move) the throotle when depressed kills the motor or bogs it down even more then it already is. My attempts to fix this are new timing gear and chain cap and rotor the timing is set but yet the motor just sits there and barely runs and I want to emphasize when I move the throttle it either kills the motor or bogs it down. Where is the next place I should look for a cure? TPS? IAC?
  • mullins87mullins87 Member Posts: 959
    Is it getting enough fuel and air? My guess is the fuel pump isn't pumping enough fuel, or the fuel filter is so clogged that enough fuel can't get to the engine. Is this engine injected? I thought it would have a carb.
  • mullins87mullins87 Member Posts: 959
    It DOES infact have a timing chain and NOT a timing belt. It is possible that your timing chain could have jumped time, but usually it will fall behind, not jump ahead. There's an ignition pickup where the distributor used to be - older engines had the distributor while your newer engine just has a small module mounted in that spot. This module IS mounted on a shaft just like the distributor and it could be slowly rotating in its mount if the hold down bolt is somehow working loose.

    Checking the timing again would be my next move. If it's off, retime the engine and put some Lock Tite on that bolt.
  • jeepachejeepache Member Posts: 8
    yes its MPI I used my fuel pressure tester and im getting 39 psi constant at the fuel rail no matter if I have the regulator vacuum on or off. I also replaced the fuel pressure regulator. fuel filter is also new
  • mullins87mullins87 Member Posts: 959
    Have you checked that pressure with the engine revved up? Sometimes a bad fuel pump will pump just enough fuel to keep the engine running at idle, but not enough to do anything else. You might try disconnecting the return line to see how much fuel is being sent back to the tank. Should be a considerable amount.
  • mullins87mullins87 Member Posts: 959
    With it being injected, the TPS could be the culprit. When you depress the throttle, the TPS tells the computer to send more fuel through the injectors. Well, if it's not doing its job, then when you crack open the throttle plate the engine leans out and dies.

    A repair manual should give the acceptable range of resistance for an operable TPS. Using a Ohm meter, test the sensor to see if it's bad.
  • mullins87mullins87 Member Posts: 959
    You started the Jeep, heard a "pop", the check engine light came on and now it's running rough??? You probably have a blown head gasket.
  • jeepachejeepache Member Posts: 8
    ok ill try that but would it make the motor at idle speed run really rough? shouldnt it be limited to whe you use the throttle? Mine idles really rough and sometimes will die on its own.
  • mullins87mullins87 Member Posts: 959
    Well, typically a rough idle is caused by either a large vacuum leak or bad IAC motor. However, in your case, it is possible the throttle plate may not be closing properly.

    How does the exhaust smell at idle? Does it smell like it's running lean or rich?
  • mullins87mullins87 Member Posts: 959
    I really wish I could be more help. But I'm the type that has to be there to see, hear and smell everything. I'm afraid my diagnostic skills are severly limited on the computer.
  • jeepachejeepache Member Posts: 8
    Well I figured it out.....I wnet to move the jeep for the first time since it was brought to me andwhen I put it in reverse and let the clutch out the engine roared to life for a minute then started squealing and shuttering. So I crawled underneath and noticed that two of the bell housing bolts had snapped and one was completely missing and there was brake fluid everywhere. So I pulled off the transmission/transfer case and lo and behold the clutch slave cylinder and blew apart and the main body of it had stuck itself to the input shaft of the tranny. so I replaced the bolts and slave cylinder and the thing runs like a champ..My theory is when the bolts snaped the transmission and engine seperated enough to put a bind on the motor and was bogging it dont so much that it wouldnt run right..I also had to replace the crankshaft sensor it had chewed through the sensor.. SO chalk this one up as a learning experience for me and anyone else. Do jeeps have a problem with transmission mounts going out. How do I tell if mine is or if its just extra rearend play?
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