Hi, I am the proud new owner of a 97 grand cherokee 4.0 and could use some help. First off, it will stumble on take off about once a week and it always spark knocks on acceleration and seems to be getting worse. It has 102,000 miles on it. I was going to change the fuel filter but was told it is in the tank so I don't know if I can change it. I have only had the GC for about 6 months and all I have done is give it new plugs, wires, cap, and rotor, and front O2 sensor. Also every time I put the it in park, the engine almost stalls. I have no idea what the previous owner has done but the plugs looked original so probably nothing. I'm suprised the plugs still fired since there was almost no electrode. Also there is air coming in under the windshield that is kind of uncomfortable in the cold weather. I have played with the climate control but cannot seem to get these to shut off. There is two spots, one at the passenger and one at the driver side both where the windshield and dash meet. I guess they are fresh air vents. Is there a way to turn these off? I have had no luck finding a way. The GC did not come with a manual so I am having to learn on my own how everything works. Luckily it's not too hard a job to learn, even for me. Sorry so long, Thanks for any help.
Newbie needs help, Please
- Thread starter tigrboy
- Start date
MudderChuck
New member
I don´t know the 91 as well as earlier models. My wifes 95 is the same series as yours (or should be). Her´s recommends (allows regular gas) but I noticed it thumps pretty good on regular, like the timing was retarded a bit too much. Is yours an octane or advance rattle or a thump. There are half a dozen sensors, that control timing for the motor. Cranks but fails to start is a common symrtom of a CPS. Temp. sender for the computer, cam position senor in the distributor even the MAP and throttle position sensor.
Does the 91 have an EGR, if it does, I´d plug the vacume line to the actuator solenoid, just see what happens.
Does the 91 have an EGR, if it does, I´d plug the vacume line to the actuator solenoid, just see what happens.
Bounty__Hunter
Super Moderator
Sounds like an XJ since it has the 4.0L, maybe with the 'Grand Wagoneer' trim package (woody wagon?). I dunno.
OOPS, stupid me, my car is a 1991. The Grand cherokee is actually a 1997. I don't know where my head was when I wrote this. Sorry about the confusion. It sounds like an advance rattle, I haven't tried higher octane gas yet. It never had this rattle before, it just seems to have started about a couple weeks ago.
Bounty__Hunter
Super Moderator
Most of the 4.0L engines develop 'piston slap' which will cause an annoying yet harmless tick in the engine.
MudderChuck
New member
The nature of the beast, the piston skins the side of the cylinder as it gets near the top. Newer models of the 4.0 or so I´ve heard, tried a couple of fixes in the piston/cylinder. One was a teflon coating that has been known to flake off.
Most of the older 4.2 and 4.0 motors I´ve been inside of, had some serious wear near the top of the cylinder (cone shape)(a moderate to serious ridge at the top of the cylinder, very little wear at the bottom). Never really seemed to hurt them much.
A look at the recall list for the 97 might tip you off, to what may be happening. I´ve heard of some piston noise problems in late models, didn´t pay much attention, my newest is a 95.
If you can live with my typos and moderate dyslexia, I can live with your mistakes.
Most of the older 4.2 and 4.0 motors I´ve been inside of, had some serious wear near the top of the cylinder (cone shape)(a moderate to serious ridge at the top of the cylinder, very little wear at the bottom). Never really seemed to hurt them much.
A look at the recall list for the 97 might tip you off, to what may be happening. I´ve heard of some piston noise problems in late models, didn´t pay much attention, my newest is a 95.
If you can live with my typos and moderate dyslexia, I can live with your mistakes.
sparkyshotrods25
New member
its spark knocking because your timing is too advanced.I would check to see where its at.I think it should be at a steady 0* i would check that first check that out.
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