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Jeep Cherokee Grand Cherokee Engine and Performance Problems



  • hello, I have a 2001 jeep grand Cherokee limited wheel drive with a 4.7. I recently had a bent exhaust valve in #7 cylinder. The guide to one of the secondary chains broke and i jumped time. I took it apart, had a valve job done to that head , then put it back together with a new gasket kit. I also put new plugs in it. It runs like crap, like its running on 7 cylinders. I did a compression test and all 4 cylinders on that side have close to 150. the check engine light is on sometimes bu not much and when i took it to auto zone to get the code it came up bad O2 sensor on #1 Bank and that it was running lean. I'm not sure which bank is the #1. It wont idle on its own hardly ever, and lacks power tremendously. I checked the coil packs by unbolting them, putting a plug in them and holding them by the valve cover to see if it arcs, and they all are. It seems to be running very rich now, as it smokes a little black smoke sometimes. I think it is a fuel or fire problem, but not sure where to begin. Could the O2 sensor make it run that bad? Thanks Dave
  • i have a 94 jeep cherokee sport that is overheating at idle. it has a new thermostat, flushed cooling system, new hoses. The pressure was tested and its good. however the jeep has 2 fans. one is connected to the pully and one is electric for the A/C. When i have the ac on it doesnt overheat as quickly. does anyone know what could be wrong with it. it runs great considering it has 175K.
  • The electric fan isn't just for the A/C, and it sounds as if the electric fan isn't working at all. It is run by a coolant temp. sensor which, of course, turns it on at a specific temp. While idling, listen for it to come on, especially once the engine is warmed up. If it never comes on, that sensor would be the first thing to check. If the sensor isn't the problem, it has to be the fan itself.
  • My 2000 JGC will blow hot air from the AC after driving for over 45 minutes or so. Usually after stopping and the engine cools, when I start up again the AC will blow cold then after a while start to blow hot again. Any ideas?
  • tuggajbtuggajb Posts: 646
    poss the thermo clutch on the engine fan has gone bad when cold fan dosn't turn as fast when hot fan turns faster to chack run engine to temp sut off take hand and turn fan should be hard to turn if not change clutch
  • tuggajbtuggajb Posts: 646
    sounds as if ac coil is frezzing up pos low on ac fluid have them check that
  • i have a grand cherekee .

    the thign is vibrating at 70 miles per hour.

    anyone know what may it may be

    thnaks :sick:
  • where is the sensor? I will have it changed out if thats the case.
  • can you educate me about the fans? Mine has two. The main fan connected to the belt! is that suppose to engage? Mine isnt. its at one speed. I noticed that my dads toyota fan engages when you first start it. Is mine suppose to do that. also my electric fan engages only when the a/c pump is on.(defrost or A/C) How do i find which one is screwed up and where are these sensors at?
  • Sounds like you're low on freon. Have it checked.
  • Sounds like your fan clutch may be bad. The main fan (mechanical, belt driven) should be turning whenever the engine is running. Replace that and let me know if that solves your problem and if you have any more questions.
  • today i let the jeep warm up to the point of over heating. (please note that the fan is spinning when the engine is on.) then i turned off the engine and checked the fans resistance. its has very little resistance. i dont think thats normal. Its a temperature based fan, If its cold it should spin freely. if its hot it should have resistance. AM I RIGHT? If so i will replace the clutch fan.
  • tuggajbtuggajb Posts: 646
    your right!!!!!!!!!
  • It could be caused by several things, but the most common problem would be tire balance and alignment. If it's been a while since you've had this done, rotate and balance your tires and have the frontend aligned. Before you do this, make sure that your tires aren't just worn slap out and need to be replaced. If you have good tires on your truck, the earlier mentioned service might take care of your problem. Let me know if this helps.
  • ok. im still overheating. flushed radiator, new thermostat, new fan clutch, new electric fan sensor switch. anyone have any ideas? tell me how it could be the water pump. does anyone know how to check the pumps pressure?

    This is whats happening. It warms up. if its at idle it will gradually overheat. when i drive the temp will suddenly drop below 210 at normal operating tempature. whats going on?
  • I don't have a GC but have had similar issues with a Cherokee , Dakota and Ram PU . It was the Goodyear tires. They just wouldn't ballance. On all I switched to Michelin and the problem was gone. I won't get a vehicle with Goodyears ever again. I am currently looking at a GC Diesel and the dealer is going to switch the tires before I even pick it up. Just a thought.
  • leo01leo01 Posts: 3
    Thanks found the problem a bought a relay from auto zone that was bad took it back and bought one from the dealer. It's been three weeks and it works fine.
  • leo01leo01 Posts: 3
    I have a 2005 jeep grand cherokee and must of the ac and heater control panel is dark. I took it out but everything is enclosed in the panel, can I open it or the panel has to be replaced.thanks for the help
  • Ok I need your help guys, (my husband is no help at all) I have a 94 Jeep Grand Cherokee 6 cylinder. The problem is the jeep won't start plain and simple right? No, the jeep started by taking longer and longer for the fuel pump to kick in, 5 seconds, 15 seconds, 5 minutes, 10 minutes, then nothing. Had a diagno0stic run and we didn't get any error codes, so we replaced the crank shaft position sensor and it started and ran fine for one whole week, then back to the no start buisness, fuel pump is not kicking in...has to be the fuel pump right? $350 later we have a new fuel pump installed and still no start, no pump kicking in, Now I have a jeep in my garage that doesn't move and still no idea what the problem is, IT"S IN GREAT SHAPE!! I would hat eto have to junk it because we can't figure out what's wrong..PLEASE help me :mad:
  • Well I'm an 18 year old girl who knows NOTHING about cars. I have a '99 Jeep Cheeroke Sport that "chugs" on me ocassionally, sometimes stalls entirely. It usually "chugs" within the first few minutes; so before it warms up. It back fires through the intake, sometimes it helps to pump the gas pedal. I have replaced the coil, throttle position sensor, and the mass air flow sensor, and it continues to "chug." I've taken it to a dealer who was utterly clueless about the issue. Dealer wanted to replace all "primary ignition components," but would not guarentee that this would solve the problem and this would be at my expense. When I told them this was unacceptable, they told me to wait until it gets worse i.e. causes an accident!! By the way, this was a FIVE STAR dealer in METRO-DETROIT. Can anyone help? I'm just about on walk mode and cannot be seen in a mini-van :)
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