dssorc68

Jeep Cherokee Sport
2001 2wd 4.0 AW4
165,000
Ok this all started about 3 weeks ago. I have a leak and need to fill about a qt. a month but was Very Low so I had to add 2 I SCREWED UP and added ATF +4.

Right away my Very Smooth shifting and running jeep went to *****. Supper rough and bogs down till almost stall at Lights.

Gets Worse, NOW its doing something new, Its hard to discribe but its almost like its "out of time" and will bog down and stutter and not shift at all mostly. Then when Taken Out Of Gear and Reved up it does something real strange and Revs UP and DOWN up and down over and over at a steady rate. Till I shut it off and restart. then it runs MUCH BETTER for a bit.

Please tell me my trans isnt Toast....

what I tried so far...
Ok Right after I figured out that i put the WRONG fluid in an OLD trans like mine... by searching HERE I drained and filled 3 times so far. then Am doing it again 4 more times tonight. getting much cleaner fluid out now but still runs bad and shifts bad. Bogging down at lights when in gear at a stop.

Is something else wrong?? I swear it ran Perfect shifted smooth right when it was suposed to and idle'd perfectly smooth in and out of gear. Right before I dumped that 2 qt.s of ATF+4 in lol.

Please ANY help whould be GREAT. I cringe at the thought of bringing it into the trans shop blind.....

Thx
Sean

tjwalker

While it is very possible that the ATF+4 is screwing with your transmission, (I do NOT recommend it for the AW4, use Dex/Merc III compatible only), your symptoms point to something that could also be electronic.

First off, are you driving it for a bit between drain and fills? Important that you do that.

If drain and fills don't fix the symptoms, the #1 sensor involved with shifting characteristics of the AW4 is the throttle position sensor. Here is more on that very important sensor. Not saying that is your problem, but it is very important not to get tunnel vision when troubleshooting any automotive problem.
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The throttle position sensor is connected to the throttle shaft on the throttle body. It sends throttle valve angle information to the PCM. The PCM uses this information to determine how much fuel the engine needs. The TPS is really just a simple potentiometer with one end connected to 5 volts from the PCM and the other to ground. A third wire is connected to the PCM. As you move the accelerator pedal with your foot, the output of the TPS changes. At a closed throttle position, the output of the TPS is low, about a half a volt. As the throttle valve opens, the output increases so that, at wide open throttle, the output voltage should be above 3.9 volts. Testing can be performed with an electrical meter. Analog meter is best. You are looking for a smooth sweep of voltage throughout the entire throttle band. While slowly opening and closing the throttle, take note to the movement of the voltmeter needle. There should be a direct relationship between the needle motion to the motion of the throttle. If at anytime the needle moves abruptly or inconsistently with the movement of the throttle, the TPS is bad

You should have 5 volts going into the TPS. At idle, TPS output voltage must be greater than 200 millivolts. At wide open throttle (WOT), TPS output voltage must be less than 4.8 volts.. The best is to use an analog meter (not digital) to see if the transition from idle to WOT is smooth with no dead spots. With your meter set for volts, put the black probe on a good ground like your negative battery terminal. With the key on, engine not running, test with the red probe of your meter (install a paper clip into the back of the plug of the TPS) to see which wire has the 5 volts. One of the other wires should show .26V (or so). The other wire will be the ground and should show no voltage. Move the throttle and look for smooth meter response up to the 4.49 at WOT.

Perform the test procedure again and wiggle and/or tap on the TPS while you watch the meter. If you notice any flat spots or abrupt changes in the meter readings, replace the TPS.

The TPS is sensitive to heat, moisture and vibration leading to the failure of some units. The sensor is a sealed unit and cannot be repaired only replaced. A TPS may fail gradually leading to a number of symptoms which can include one or more of the following: -

NOTE: The throttle position sensor is also DIRECTLY involved with transmission shifting characteristics! It should be verified early in the troubleshooting process, when a transmission issue is suspected!

• Poor idle control: The TPS is used by the ECU to determine if the throttle is closed and the car should be using the Idle Air Control Valve exclusively for idle control. A fault TPS sensor can confuse the ECU causing the idle to be erratic or "hunting".
• High Idle Speed: The TPS may report faulty values causing the engine idle speed to be increased above normal. This is normally found in conjunction with a slow engine return to idle speed symptom.
• Slow engine return to idle: A failing TPS can report the minimum throttle position values incorrectly which can stop the engine entering idle mode when the throttle is closed. Normally when the throttle is closed the engine fuel injectors will be deactivated until a defined engine RPM speed is reached and the engine brought smoothly to idle speed. When failing a TPS will not report the throttle closed and fueling will continue causing the engine to return to idle very slowly.
• Engine Hesitation on Throttle Application: The TPS is also used by the ECU to determine if the driver has applied the throttle quicker than the Manifold Air Pressure sensor can read. The fueling is adjusted accordingly to cope with the sudden increase in air volume, however a faulty sensor can cause the ECU to ignore this data and the engine will "hesitate" when applying the throttle. In extreme cases with the engine at idle, a sudden application of full throttle can stall the engine.
• Engine Misfire: A fault TPS can report values outside the denied acceptable range causing the ECU to incorrectly fuel the engine. This is noticeable as a slight misfire and can trigger the misfire detection software and/or Malfunction Indicator Lamp (MIL) light on the dashboard. Extreme cases can cause excessing misfires resulting in one or more cylinders being shut down to prevent engine and catalytic converter damage.

dssorc68

Wow thanks alot for that Detailed reply . I can get a meter at work tomorrow and test it. gonna be digital but best i can get right away.
I'll start with that first. will there be any error code for the problem? can take it to autozone after work and get it hooked to a code reader.

I have been driving it atleast 10 miles inbetween draining the fluid and changing. seems to drive Better at first untill this last one i did tonight.
Thats when that Strange Reving Up and Down out of gear when ever I wud put on gas. would rev up to whatever rpm and back down real fast back and forth. would have to restart for it to go away. Would that be anything to do with the TPS? its preseded by the Transmission running and shaking and shifting like crap. but only does it sometimes but getting more often.

bassboost

Agreed on TPS, as well as, recommended fluid being DEX3. Dumb question, is the fluid level correct?

My transmission had completely disabled itself because of the TPS, its symptoms were..
Studdering
Running rich (soot from exhaust present)
Slipping
Wouldn't shift from 1st to 2nd when cold until 3k rpm's or higher
Eventually, wouldn't go into any gear, it would just rev up as if it were in neutral.

TPS's are apparently a known maintenance item over item. They're like $30 from autozone, I'd replace it for peace of mind.

dssorc68

Yeah I was careful everytime I refilled the trans. If the TPS even seems ify tomorrow when i test with a meter ill get a new one. its 65 at autozone here but an easy replacement to see if it helps.

bassboost

Ouch lot more pricey where you are! Let us know how it goes!

Radi

Bad TPS can mess with your engine AND transmission.

dssorc68

Ok I Tested the TPS as per the Instructions and it didnt Test the same numbers, so long story short I replaced it. I must say I think my Idle IS BEstter alot better and shifts better almost perfect

UNTILL...

That strange bogging down its been doing. then the rev up and down up and down out of gear even with steady throttle, UNTILL shut off and restarted.
Tried to pin down when it happenes cuz its not all the time. I THINK its mostly in the morning when its cold. AND when I come to a quick stop in gear starts running rough then when I take off bogs down till I take it out of gear then does that rev thing till I restart it.......

ALSO got the codes Read at autozone...

Lol was 5 of them.....

p0132
p0300
p0303
p0304
p0305

Now I understand the first is a BAD O2 sensor, first up stream one, guess theres 4?!?!

Then the rest are Multiple MisFire and Misfire on 3,4,5....!!!

It doesnt run that rough that I wud think its running on only 3 of 6???
It Idles fine now that I changed the TPS and while it feels UNDER POWERED doesnt feel like half are misfiring... No back fireing or studdering like its skipping EXCEPT right before it does that rev up down thing.....

Im at a Loss..... Guy at autozone said to replace the coil for 3,4,5 but as everyone knows its a Coil Rail. Just changed the plugs 2 months ago ran great after. checked to see if it was pluged in right lol.

Should I replace the Coil Rail ?!?!?!? will that fix the MisFires or is it something else??

What else should I look for??

Thx for all the help BTW Would be lost.

dssorc68

• Engine Misfire: A fault TPS can report values outside the denied acceptable range causing the ECU to incorrectly fuel the engine. This is noticeable as a slight misfire and can trigger the misfire detection software and/or Malfunction Indicator Lamp (MIL) light on the dashboard. Extreme cases can cause excessing misfires resulting in one or more cylinders being shut down to prevent engine and catalytic converter damage.[/QUOTE]


BUT I Replaced the TPS and Still getting the misfiring. Codes were read after I replaced it. Could Just 3,4,5 o out on the coil pack...???

Would really like to know if the Coil is involved before I go pay the 104.95 they want for one lol

Radi

Ran great for 2 mos after changing the plugs...but now it's bad again? What type plugs did you put in? Bosch by chance?

dssorc68

No........ I changed the plugs 2 months ago before ALL this started the problems with the Trans and The MisFiring on 3,4,5....... But YES the Old plugs Where Bosch..... I know not to put them In used other ones.

No My problem is that I replaced the TPS and Still am getting a Misfire on 3,4,5 acording to the Code reader AND that strange bogging down like its out of time, then Reving up and down out of gear when ever I give it gas till I shut it off and restart.... Has Nothing to do with Plugs bosch or other. was just mentioning that I yes have replaced the plugs and there good.

Should I replace the Coil Rail like the autozone guy said or was he just guessing???

What could make it misfire on 3,4,5 all at once??? Any help please this is driving me crazy. guess Im gonna have to bring it to a shop gotta solve this.

Radi

Have you replaced the O2 sensor yet?

Do you have access to a code scanner that displays live data? It would be useful to watch the output of the O2 sensors (fuel trim) and the crank sensor. I think you probably have a bad sensor somewhere and the ECU is chasing it around.
I'd hold off on the coil rail momentarily, they fire cylinders in pairs. I'd think you'd have either 2 or 4 misfire codes, three wouldn't make sense. Not that a failure isn't possible, but it wouldn't be my first choice.

dssorc68

No I didn't buy the rail yet gonna get the O2 sensor tonite after work and put it on in the morning. I don't have access to a reader that does live readings, don't think. Just the one they rest with at AutoZone lol.

Also Tjwalker mentioned to check the fuel pressure make sure its at 45 +/- 5 lbs. Gonna fine a place to borrow or rent a gauge today or in the morning.
Thx for the heads up about the coil firing in pairs didn't know that ur right it doesn't make sence with 3 misfires gonna hold off on that till I check the pressure and replace the O2.

Thx for all the great advice I can replace just about anything with the right instructions but I'm not the best troubleshooter.

Radi

For future reference, the following cylinders are fired in pairs:
1 and 6
5 and 2
3 and 4

Radi

NM. Another double post.