Newbie, and a few questions

Hi all,

Another newbian here, I found out about this place on the colorado4x4.org site.

I just bought a 99 Cherokee Sport. It has 80k on it and is in perfect condition, and the best thing about it is, it’s a 5 speed! Boy, finding one with a manual trans was difficult, they must not have sold too many.

I gave it a tune up over the weekend (plugs, wires, cap, rotor) and added a K&N air filter. It didn’t appear that it ever had a tune-up, the wires looked original and the plugs were pretty worn as was the cap & rotor.

I do have a few questions about it though:

The engine seems to “ping” a lot while accelerating. (The dealer filled the gas tank for us, so I’m not sure what grade of gas he used).

Also, between shifts, the RPM doesn’t drop. If I shift at 2500 RPM, it holds that RPM for 2 or 3 seconds when I depress the clutch. Makes it kinda strange to drive.

Anyway, so far so good!

Dave

For the ping you might want to try a chemical treatment such as GM top engine Cleaner. This is stuff you dump down the throat of the throttle body, stall the engine, let it sit, then restart. You'll get a huge cloud of noxious smoke, and a little vacation from knock. I think maybe the 5-speeds are more knock-prone because they're geared so tall that you're always lugging. My 95 has always knocked, and likes a chemical "enema" every year or so.

In the meantime, a bottle of Techron or the like in the fuel couldn't hurt either, and do keep an eye on the tach, because this engine has a lot of grunt, and it's fairly quiet, so you might not realize at times when you're cruising in fifth gear at what really amounts to idle speed. I haven't done a scientific/record-keeping study, but you might even get better fuel economy if you forsake fifth more and try to keep the revs up in the 2000 range.

I don't know what's going on with the idle speed, but a good place to start might be to see if the throttle body, including the idle air controller, needs cleaning, and check for vacuum leaks. The engine computer will adjust idle even under unusual conditions, but there's a little delay if it has to compensate for a fault.

Congrats on the new Jeep. 5-speeds do seem to be pretty rare, especially in the later ones. I imagine it's partly just the trend these days, but in the case of the XJ, it may also be because the AW4 automatic has to be one of the best automatic transmissions ever made.

Give the throttle body a good cleaning but be careful of the sensors, they are plastic and sensitive to the carb/FI spray cleaners. Best method is to remove the TB, clean it on a work bench then reinstall.
Dump a LARGE bottle of Chevron Techron, the bottle for the 'will treat 20 gallons' size into the tank.
Check your tire pressure, helps big time milage wise.
Change the oil and all the other fluids. Cooling system too, bet thats never been touched from the description of the plugs and wires.
Stop at dealer and pick up:
Thermostat and gasket
Serpentine belt
Pressure cap
2 gallons of Mopar coolant
From a local grocery store pick up 2 gallons of DISTILLED water.
Drain system, replace tstat and serpentine belt. Remove the overflow bottle and dump it, clean it out with fantastic, 409, etc and reinstall it, fill to between the cold and hot marks with 50/50 mix.
Dump gallon of pure coolant in and a gallon of distilled water.
Use the remaining to make up two 50/50 mix bottles and start burping the system with the engine running.
You can go one step further and refill with water and 7 hour prestone flush then follow the directions, oh, and a back flush kit into the heater hose. Getting a mite cold up there now to do that though. The 7 hour flush will actually break down build ups vs the 15 min flush that basically blasts the system. I've had too many water pump failures after using 15 min flushes.
Then I would do the transfer case and tranny, dealer has the correct oil for the tranny but hold on to your socks when you see the price but it's the safest lube to use.

Matthew Currie said:

Congrats on the new Jeep. 5-speeds do seem to be pretty rare, especially in the later ones. I imagine it's partly just the trend these days, but in the case of the XJ, it may also be because the AW4 automatic has to be one of the best automatic transmissions ever made.

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All our jeeps are 5 speeds, daughters TJ intimidates her boyfriends because none of them know how to drive a stick, funny really. Actually even her girlfriends are amazed and I've overheard a couple of times 'man, you know how to drive a stick shift, awsome', they just had better have been talking about a manual tranny or else :hang:

Thanks for all the info!

I didnt think about the TB sticking, I will have to check that.

I also replaced the belt when I did the tune up (I forgot to mention that!).

As far as the t-stat, which temp range should I use?

Also, are there markings on the diff that would tell me if the rear end is limited slip (it does not have ABS)?

Thanks!

Dave

I have always used 89 octane fuel in my Jeep because I believe it comes with higher quality additives and is just better than the bare minimum 87. It is extra insurance against knocking and to help the engine run better and last longer. I believe the dealer only supplies 195 degree thermostats, but I picked up a top of the line NAPA 180 degree a long time ago and seems to help Jeep cool and run better.

Crown said:

I just bought a 99 Cherokee Sport. It has 80k on it and is in perfect condition, and the best thing about it is, it’s a 5 speed! Boy, finding one with a manual trans was difficult, they must not have sold too many.

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I believe dealers are the cause of the manual tranny's downfall. They NEVER stock any... based on the "nobody buys any" rule. Well, hell, maybe if you HAD SOME, folks would buy them!! Most folks buy from dealer stock, don'tcha know.

I could also call it a conspiracy. Sticks don't require a $300 fluid-and-filter change every 30k. That's a lot of lost three-hundred-dollar checks in the course of a year.

Add in the fact that Jeep was in the midst of a changeover from the AX15 tranny to the NV3500 (I was not allowed to order a 5-speed in my 2000, they were on "indefinite hold"), and you end up with an extremely auto-heavy mix.

Den

DenLip said:

I believe dealers are the cause of the manual tranny's downfall. They NEVER stock any... based on the "nobody buys any" rule. Well, hell, maybe if you HAD SOME, folks would buy them!!

Den

Click to expand...

Probably true!


Kinda strange; we looked for a 5-speed for a few months...nothing. Then, all of a sudden there were two 5-speed 99's in the paper, same colors, and almost the same miles, but from two different sellers.

Called on one; it was sold.

We looked at the other one and bought it.

DenLip said:

Sticks don't require a $300 fluid-and-filter change every 30k. That's a lot of lost three-hundred-dollar checks in the course of a year.
Den

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Neither do the autos if you know what your doing...

For all those that don't, I'll do it for a cool $125.00 :exclamati

The symptom of the rpms not dropping is most likely just a sticky throttle cable or the lack of a return spring. Personally I recommend a can of BG44K in the fuel to clean the injectors and get rid of ping. Since you are here in Colorado and at higher altitude, ignition timing is an issue. You can't really adjust it, the computer does, but vehicles sold at this altitude came with a high altitude crank shaft position sensor to help advance the timing. If all else fails, you may want to check to see which one you have, the low or high altitude sensor. At the moment I don't have time to elaborate on how to tell the difference, but if and when you get to that point, repost and I'm sure someone can give you a picture and some instructions.

old_man said:

The symptom of the rpms not dropping is most likely just a sticky throttle cable or the lack of a return spring. Personally I recommend a can of BG44K in the fuel to clean the injectors and get rid of ping. Since you are here in Colorado and at higher altitude, ignition timing is an issue. If all else fails, you may want to check to see which one you have, the low or high altitude sensor.

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Ok, so it sounds like the RPM not dropping is more of a mechanical problem. At first I thought it was a sensor or something not working correctly. I know it does have a return spring, but I will check the other things when the weather clears up a little.

I know it was sold new in Longmont, so hopefully it has the high altitude stuff. I'll cross that bridge when I get to it!

Thanks

Dave