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Jeep Grand Cherokee Maintenance and Repair



  • Still having red line fun? If you didn't find an air leak like one of the other guys suggested, you might investigate the crankshaft position sensor (CPS). When I was having some glitches with my CPS, on one reinstall, the engine did what you describe. Well, not to red line, but definitely ran away. After another remove, clean and replace, it worked fine. It's a [non-permissible content removed] to get at. Behind the right exhaust manifold on the block where the bell housing bolts on. Might be worth a look.

    Good luck --- Clip
  • My '89 was doing the same thing awhile back, I'd have to shut it down. Difference is that after a couple of times, It'd get it's act right. You have cruise control? Was thinking about it awhile, you checked the throttle plate, Have you checked the Idle air motor? Maybe doesn't even have one, I don't know. Pintle doesn't move thoroughly and smoothly, the machine won't idle correctly. DON"T move the pintle in or out manually, messes 'em up, supposedly. I'd disconnect ALL linkage/sprin gs, etc. from the throttle-body and try it again. Hold the throttle shut with your hand, or something. Let someone else start it though, so's you might visually check the the mechanics of it all. I don't know what would happened if you were to remove the Idle-air-control motor and, CAREFULLY, metered the "controlled" air flow into the idle-air circuit manually. ie Shove a finger or such into the port the idle motor come from, stop or slow the air flow from the port inside, the port, and see what happens. Leave the motor connected to the harness, set it carefully somewhere safe and observe it's operation while you are at it.
    Oh, the cruise control..... Had a friend long ago, ME, got some vacuum hoses twisted around, and when I thought the'y'd "ONLY connect to those ports one way", It wasn't right at all. Vacuum came up -- so did the rev's--so did the vacuum--so did the rev's, etc.
    Scarry stuff isn't it? Spine jumps right out of the skin, huh?
    At the time mine was acting-up, I'd considered making a plane out of it.
    Just wouldn't have been as much fun though.
    You be careful, patient and consider, carefully, what's going on, and you'll be just fine. Have fun.
  • paulepaule Posts: 382
    I'd also check your throttle cable again. It almost sounds like it's "hanging" wide open. I had a Dodge Avenger way back when that the dealer replaced the head gasket on. When they put it back together, they hooked the cruise control return spring up wrong. So, the first time I used the cruise control, guess what. Yep, wide open throttle. I had to kill the ignition but not lock the steering column and muscle the car over to the side of the road.
    You should have seen the look on the face of the service manager when I took the car back in for them to check it out and I told him what had happened!
  • I just replaced a CV axcle on the drivers side and now the jeep is shaking (steering wheel) whenever I drive over 50 mph and I am not sure why? I should also say that the gears in the hoghead are bad so I also took the front driveshaft out to try to alleviate the the grinding noise I would sometimes hear .Can anyone pass on some suggestions?
  • tuggajbtuggajb Posts: 646
    first of all i would also remove the axel shalfs as if the gears lock up you will realy go for a ride you will not enjoy also prob brake the front axel housing also

    the shake could be that you did not get the front hub in strait when you tightened the 3 bolts that hold it in make sure that you didnt get dirt behind it (between the mount serfus and the hub)
  • I very much appreciate the help , would you mind breaking that down a little bit more as far as what I need to do to fix this because I am learning as I go .
    Thanks ,
  • tuggajbtuggajb Posts: 646
    when you changed the front axel shalft you had to remove the front hub to get the shalf out as when if you run the jeep the gears turn in the punkin so if the bearings are going bad they can get stuck and freze up in the housing lock up tight and stop you when you leaste expect it even with the drive shalft out the axels still turn the gears when you move so if you are not going use 4 wheel drive take out the axel shalfs and drive shalf and go for it
    here is a url that you can use to see what you need to do,L001/UserAction,logout/getInTheZone.htm

  • Hi, At this point I have been reading many different choices on what to do, to get this problem fix. I am low on budget so, if someone could just be able to direct me the best way on saving money and maybe fixing my problem.

    My 2001 Jeep Grand Cherokee Limited comes with a dual electronic AC/Heater control. AC works excellent. No leaks. Radiator tank is always fine on level. When turning up the temperature to get the heater runningl; nothing happens. Air goes from cold to a regular blowing temp. When weather is kind of cold and car has been running for a while you are able to see some fumes coming thru the vents. They smell like antifreeze but I have never found any leak below the dash nor below the car. Would anyone guide me in the right direction in order to try cheap things first and than go from there.

    I've heard it could be the heater core, motor blowers..

    Anyone that could help me, really much appreciate it.

    Thanks alot.
  • I took the jeep back into the garage after the tranny rebuild and torque converter replace and the vehical was still shuddering and they gave it to another mechanic and started checking other things and found out that there was a faulty ERG valve with very erratic voltage and pulse width -- replaced ERG valve and as of now I'm not noticing the surging any more . It was acually the engine that was making the jeep shudder . Will update after a month or so . ;)
  • You need to replace your font differiential gear nest. This composes of a ring gear, spider gears and new ring gear bolts. The shims are already there on each side of the spider gears; don't mix them up, and put them back in the same order you found them from. If you take the front drive shaft off to make the vehicle into a 2 wheel drive, this is going to create ALOT of problems you don't want to deal with.
    When you replace the gear nest, the pinion gear (the one where the front driveshaft connects to should not be tampered with, for it does not need to be removed. If the pinion gear, is in fact, the one that is damaged, then replacing it will be more difficult than you think, because there is in fact what they call a "crush" sleeve. This sleeve sets the load/preload for the differential in order to set the lash/backlash for the gears to mesh properly.
    I hope this helps you, and good luck m8.
  • Air goes from cold to a regular blowing temp. What does this mean? Are you getting any warm air at all? Is the blower motor working on all settings? As for the fumes, this sound like you have a coolant blockage at or near your heater core. The cheap way of possibly fixing this problem, is to get the cooling system flushed. You can have this professionally done, or do it yourself. I myself do my own.
    Try this: you can go and get an off the shelf bottle of coolant flush and use as directed which probably will fix your problem (fingers crossed). Or you can try this: drain the system of coolant. Take the thermostat out and refill the system with water. Add dishwasher washing crystals to the radiator (about 4 cups). The crystals act like sandpaper and blast away the built up crud from years non- preventive maintainence.
    Drain the system from the lower radiator hose, refill with water, let run for awhile and drain again.Repeat as needed until most or all of the crystals have left your cooling system.Replace your thermostat with a new one (while your at this stage anyways) and refill with a 50/50 mix of prestone coolant and water.
    I hope this helps you, and good luck m8.
  • The shaking your getting is more than likely the fact that you re-installed your front drive shaft 180 degrees from it's original position. Also inspect the drive shaft to see if any of the small balance weights have knocked off recently. Are the universal joints in good condition, and no parts missing? Most shaking in the front end can be attributed to lost tire balance weights, mud or dirt on the inside of the tires, separated or worn tires, unbalanced front drive shaft or a worn front end dampener shock.

    I hope this helps you, and good luck m8.
  • tuggajbtuggajb Posts: 646
    if you replace the ring gear you also have to replace pinion gear as these are matched sets
  • The pinion does not have to be replaced if your replacing the gear nest with the original gear ratio. If your swapping out gear ratios ie: 373 ratio to a 410 ratio, then yes, everything must be changed to match each other.
    The diff in your particular year is more than likely a spicer35 in the front, and a spicer 30 in the rear. These are the most common setups in jeep products. Talk to any gear centers, or driveline centers in your area about replacing the gear nest in your diff.
    By the way, i've replaced 20+ gear nests over the years, and never had to replace the pinion; unless the pinion was damaged, or needed replacing.

    I hope this helps you, and good luck m8.
  • I hope you got your tranny fixed, but if not then.....
    I cannot see internal transmission failure, because you state that in fact there is smooth gear transitioning. I assume that other than using more fuel to get you where you want to go everything else is fine regarding the transmission. There is a governor sensor located inside the transmission pan, and that needs to be changed. I would have a compentent shop or dealership do the work, (it really is messy work), and since your at the point, changing your transmission filter is a very good idea (about $30 ). A good idea for the first 2 weeks after the fix, is to put cardboard on the ground under the transmission. Or just keep an eye on it. Transmission pans have a tendency to leak from the bolts loosening off, and will need to be re-torqued to spec, unless you ask them to use lock-tite on the bolts.

    I hope this helps you, and good luck m8.
  • if your fan works with the air on and your problem is no heat then it is the flaps in the blower housing that are not directing hot air into the cabin. had the same problem and i went to this forum and was directed to a company called heater treater. they sell a product that is specifically made for this problem. was easy to do and only took 45 min and cost $145 heater has been working great since, it comes with full idiot proof instructions, hope this helps.
  • Start engine--run til hot--feel the two heater hoses near where the enter the firewall connections. If both are equally hot the water is circulating thru the heater core.
    Kill engine.Drop the golve box lid all the way down. You will need to release the rubber stops and flex the two pins on the top of the lid so that it will come all the way down.
    At the left side you will see a squarish black box attached to the blower housing.Remove the two srews holding it. Lift the housing away from the blower house(leave wireing connected). Pay attention to the shaft alignment. Turn the switch on. Set air to floor. Manipulate the heat control. If the shaft ring does not move within the motor housing do this. remove the 4 screws on the housing. Slowly lift the side off to expose the gears. Remove the three regular gears to expose the worm gear.Again manupilate the heat control. If the worm gear does not move.---Remove the tiny motor and turn the screw by hand to free it up. Again see if the motor will run. If it runs--- replace everthing. Reattach the motor housing to the blower housing and try it out again. That fixed my problem at no cost--just time and frustration Good luck--Smokey Swann---Tx
  • I have a 1995 Grand Cherokee w/ EFI, 5.2, quadratrac.
    I drove it approximately 30 miles today and it ran fine but when I took a lefthand turn three blocks from my house it just died. I tried to start it and I get the starter turning but it won't turn over.
    I thought it might be the fuel filter so I let it sit for about an hour thinking that if it was clogged the sediment might settle but got the same result.
    Any suggestions?
  • Did the engine turn over? Was voltage near 12 with the key on? If the engine turned with the starter but the volts were below about 10, you may not be getting ignition, and fuel might also be a factor if voltage is low. Sorry I can't tell you for sure what to poke at.

    Anyway, at least you were close to home. Merry Christmas.

  • The engine does not turn over and I just replaced the battery two days ago.
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