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cowboisgirl 12-14-2012 11:45 AM

Stalling (maybe fixed) & Strange Shifting issues?
I apologize in advance if there are relevant threads elsewhere—I don't really have any idea what to search for. So if anyone would like to point me to the appropriate thread or term to search for, I will be happy to do so.

My 1995 Jeep Grand Cherokee 5.2L has recently developed some strange behavior. I'm not sure where to start as far as looking for what is causing the problems, and my one mechanic friend keeps telling me to just get rid of it. And the shop I've taken it into has basically said they could try replacing various parts, but that they are just their best guess (not confidence inspiring).

1) Random Stalling: we may have addressed this issue. Based on my description of the issues, Mark (my veteran mechanic friend) had me replace the plug wires, distributor, and ignition coil. Problems have not recurred since the ignition coil was replaced (it's been about 450 miles of driving since, or about two months). I mention this issue for history and context mainly. Another related note is that the trip to the shop was for THIS issue, and they didn't have any idea what was causing it. The computer wasn't throwing any codes when it happened, and the last code that HAD been thrown was for the Crankshaft Position Sensor. They wanted to replace the sensor, and conduct a fuel injection service. I didn't do either of these. Jeep has been running normal since I replaced the above parts, with the exception of the Check Engine light, which came on two weeks ago, but turned off again once the Jeep was restarted (oil level was fine), and then Wednesday, it started with new behavior (below).

2) Wednesday morning when I started the Jeep and put it into reverse and depressed the accelerator, it began to back up, but then it just seemed to lose power. The engine revs didn't change, and depressing the accelerator further revved the engine, but it didn't increase backward acceleration. Seemed almost like the Jeep had kind of slowly shifted into neutral (I say that because it was not a sudden thing, I sort of slowly lost the ability to back up). I shifted back into drive, pulled forward, and then back into reverse and it was fine that time. Then later, on my way home, I began to have more trouble after driving fine for about 10 minutes. At idle at a stop light, I got a low vibration (I thought I was going to stall), and the RPMs went erratic. I shifted into neutral again, and back into drive and was fine for 3 or 4 minutes before it started in again. Was in motion that time, so I began to lose acceleration power, and when I DID get acceleration, it seemed like the Jeep was shifting gears erratically—like it couldn't figure out the right gear to be in (RPMs were erratic too).

I made it home, and haven't dared to drive it since. I don't know enough about this stuff to guess what part it might be (thus not knowing what to search past threads for). And I don't know if the stalling problems I had in the recent past could be related.

I was thinking there might be a computerized component that controls the transmission that might need to be replaced? Or even the crankshaft position sensor? I had one fail on me before (my current sensor is 2 years old), but the behavior was very different. On the other hand, I've been told they fail in a spectacular array of ways, so I really have no idea...

Any comments or suggestions or thread pointing would be very appreciated.

I'm tired of people telling me to just get rid of her. Aside from the fact that I love her, and she's my baby, another vehicle is just not an option for me right now. If I can't fix her, she's just gunna sit in my driveway. And that makes me sad.

cowboisgirl 12-16-2012 12:37 PM

Spoke to Mark. No computerized component or sensor to control the transmission, apparently (that's how much I don't know about this stuff).

Transmission is just failing. Period. He said I could replace the one part that is failing, but with 215K miles on it, he said any transmission place would just tell me to replace the whole thing, once they got it apart.

Thought I'd share, in case the info helps anyone else...

KoreaZJ 12-16-2012 07:02 PM

You may have more than one problem.

Check for fault codes on BOTH check engine lamp and tranny OD/OFF lamp.

Learn how... HERE

cowboisgirl 12-16-2012 07:44 PM

Do you know where I can still get a code reader for it? I suspect the person who told me the following was full of it (at least a little), but I was told it was hard to get a hold of code readers that would still read the output...

accord23 12-17-2012 10:33 AM

governor pressure solenoid in the transmission is going bad.

PolkaPower 12-17-2012 10:37 AM


Originally Posted by accord23 (Post 14625370)
governor pressure solenoid in the transmission is going bad.

Nope. Not in the 93-95 years. They did not have them. 46RH = Hydraulic.

The TPS or IAC can cause weird jerky loss of power sometimes. Those are easy to test and relatively cheap to replace. When I sold my 95 5.2 is had 225k on it and was still going strong on the original motor and trans.

The first thing I would do IF I though it was the transmission is to make sure that the fluid is filled to the correct level. You have to warm it up to operating temp then shift it into N to check the fluid level. Then I would drop the pan and drain the fluid. Put a new filter in and new atf-4 and see if that helps.

To read the codes you cycle the ignition on off on off on then wait for the check engine light to start blinking. That tells you the codes. It may not be the trans at all.

Did you read the link Korea gave you? It tells you how. DO THIS FIRST

Might help you to search as its in the FAQ.. But here:

To display codes cycle the ingition key On-Off-On-Off-On within three seconds. Count the number of flashes, first digit, pause then second digit will be displayed in a series of flashes. (2 flashes, pause, 1 flash = 21)

11 - No Crank Reference Signal At PCM (Crankshaft Position Sensor)
12 - Battery Disconnected Within last 50 Key-on cycles
13 - No Change In MAP Sensor
14 - MAP Voltage Too Low Or Too High
15 - No Vehicle Speed Sensor Signal
17 - Engine Is Cold Too Long
21 - O2 Sensor Signal At Center Or Signal Shorted To Voltage
22 - ECT Sensor Voltage Too Low Or Too High (ECT = Engine Coolant Sensor)
23 - Charge Air Temperature Sensor Voltage Too High Or Low (Intake Air Temp Sensor)
24 - Throttle Position Sensor Voltage Too High Or Too Low
25 - Idle Air Control Motor Circuit Shorted
27 - Injector Control Circuit Signal Not Responding Correctly.
31 - EVAP Purge Solenoid Circuit Open Or Shorted
32 - EGR System Failure
33 - A/C Clutch Relay Circuit Open Or Shorted
34 - Speed Control Solenoid Ciruit Open Or Shorted (Vacuum Or Vent)
37 - Torque Converter Clutch Solenoid Circuit Open Or Shorted
41 - Generator Field Not Switching Properly
42 - Auto Shutdown Relay Control Circuit Open Or Shorted Or No ASD Voltage
44 - Battery Temp Sensor Voltage Out Of Limit
45 - Overdrive Solenoid Circuit Open Or Shorted
46 - Charging System Voltage Too High
47 - Charging SYstem Voltage Too Low
51 - O2 Sensor Signal Stays Below Center (Lean)
52 - O2 Sensor Signal Stays Above Center (Rich)
53 - Internal PCM Failure
54 - Sync Pick-Up Signal Not Detected (Camshaft Position Sensor/Ignition Pickup)
62 - PCM Failure SRI Miles Not Stored
63 - PCM Failure EEProm Write Denied

55 End Of Codes

These codes are good for years 93, 94 and 95.

cowboisgirl 12-17-2012 11:30 AM

I had launched the page with the thread, but hadn't read it—since I assumed I needed a code reader. That'll teach me.

The Check Engine lamp is throwing 12, 11 and 21.

The OD/Off lamp is not blinking at all. Not sure if I need to do anything special for that or not. The instructions made it sound like it would just start blinking like the Check Engine lamp did. Or perhaps I am not looking in the correct place?

In my Jeep, the OD/Off button is located to the right of the steering column, right below the defrost button for the rear window. I know the lamp that correlates to the OD/Off button is still functional, because I can press the button and the orange light will come on. And I can toggle it. Am I looking in the right place?

No other indicators come on on the dashboard either—just the Check Engine lamp.

KoreaZJ 12-17-2012 06:16 PM


Originally Posted by cowboisgirl (Post 14625711)
The OD/Off lamp is not blinking at all. Not sure if I need to do anything special for that or not. The instructions made it sound like it would just start blinking like the Check Engine lamp did. Or perhaps I am not looking in the correct place?

Right place, it doesn't always work the first time. Try again.

cowboisgirl 12-18-2012 01:01 AM

I tried it 4 or 5 times this morning with no results. But I will try again in the morning. I wondered though, if I would have more luck trying to do it right after it has acted up...?

kateean2 12-18-2012 01:20 AM

Check for fault codes on BOTH check engine lamp and tranny OD/OFF lamp.

ratmonkey 12-18-2012 06:02 AM

Check transmission fluid level.
Unplug o2 sensor
Go for a drive

O2 sensor can do this, tps can, bad caps in the computer can, crank sensor can. Fuel pressure regulator/pump...
Very first things I would do, replace both items the codes are for with mopar sensors only and check the fluid level.

cowboisgirl 12-21-2012 02:40 PM

Just re-checked the codes. The OD/Off lamp is still not producing any codes. Haven't had a chance yet to do the other things mentioned, but I will.

In the mean time, after looking up what the O2 sensor does (from the repair manual "This component of the system provides a variable voltage for the MCU that is proportional to the oxygen content in the exhaust gas."

It occurred to me to wonder if this additional piece of information is relevant at all: my catalytic converter is failing and needs to be replaced. I know that can effect exhaust.

Does that change the landscape of the problem at all? Or you'd all still start with checking transmission fluid levels, and changing the crank and O2 sensors?

cowboisgirl 12-21-2012 03:10 PM

Also, just checked the Transmission fluid level. I let it get up to operating temp by idling (and drove it back and forth a few feet in the drive way a few times), and then put it into neutral, and checked the dip stick. If I did it right, the fluid is way low—barely got the tiniest drop on the end of the dip stick. Fluid was the right color though—light pink, and clear, with no tinges of brown or black (which I believe means that the fluid that is still present is in clean shape).

ZeeJay1997 12-21-2012 03:44 PM


Originally Posted by cowboisgirl (Post 14652197)
my catalytic converter is failing and needs to be replaced.

how is it failing and how do you know this? when an engine cannot breathe, the intake vacuum will never be correct. this causes the PCM to flip out and do nasty things to the fuel mixture.

low fluid will do it every time.

cowboisgirl 12-21-2012 04:31 PM

The mechanic I first took it to for diagnostics when it was stalling on me told me it needed to be replaced. I'd known something wasn't right with it for a while—it had developed a rattle some time ago. They said that the catalyst on the inside was breaking up and flying around in it and that if I didn't replace it, the debris could eventually blow through the screen and destroy the rest of my exhaust (muffler?). I am paraphrasing, and probably not quite getting the terminology right.

Just double-checked the fluid after taking it around the neighborhood a few times (of course, it didn't act up at all). Definitely low. Am I able to add more fluid through the engine compartment, or do I need to get under the Jeep to do it?p

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