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MJ stalling when i take it out of gear.


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I have an 89 MJ w/ 4.0L and 5-spd AX-15. When I take it out of gear to neutral, then the rpms drop- sometimes to the point it stalls. I don't think that it is fuel related. I was thinking it might be a vacuum problem or maybe the EGR? Would appreciate any input you fellars might have.

Thanks.

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I'm thinking TPS. Does it recover and stay running if you tap the gas pedal a little to keep it going?

 

Yes, it will recover if I give it a little gas (IF I CATCH IT IN TIME OF COURSE!). So you think it's the TPS? That would make sense. Any special tricks/warnings to replacing it?

 

Thanks for you help!

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Nothing special...they are typically a simple remove and replace.

 

I have heard that some of the TPS on our trucks are adjustable and you should have a multi-meter to set the resistance, but I have not experienced that one and I am not sure what years that applies to.

 

Our YJ did a very similar thing, but it was a simple R&R...no adjustment.

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Man am I glad I found this site. Anyway, my 88 is stalling in the same manner. I changed the IAC, EGR valve, tested the EGR solenoid and map sensor to no avail. Am just now getting to the TPS. I saw on another site that it could also possibly be the CPS, but I really don't see how. Let's keep one another up to speed on this one.

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I saw on another site that it could also possibly be the CPS, but I really don't see how. Let's keep one another up to speed on this one.

 

CPS will cause a random stall at any speed, and is not idle-related. Very rarely the CPS will fail intermittently and the Jeep will die and then restart again. More often it fails completely and it won't' start no matter what. It's a complete pain to change because it's located at the very top of the bellhousing.

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Man am I glad I found this site. Anyway, my 88 is stalling in the same manner. I changed the IAC, EGR valve, tested the EGR solenoid and map sensor to no avail. Am just now getting to the TPS. I saw on another site that it could also possibly be the CPS, but I really don't see how. Let's keep one another up to speed on this one.

 

Well, I will try to keep you all updated, but it will be a while. It happens a couple of times per trip so I will have to live with it. I am way too busy this week to take care of it due to a bunch of new issues this week.

 

Thanks for all the input everyone, I'll let you know what's up ASAP.

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My 90 MJ has been doing this periodically over the last few months but I'm fairly sure that it's the TPS, I have changed the IAC, and tested the EGR circuit.

Does your truck do it all of the time? Some days mine will run fine then the next day it will stall almost everytime the clutch is pushed in when stopping.

 

But I am also starting to get high idle issues sometimes I come to a stop and the idle will be 1200 to 1800 rpm. This is why I'm going to replace the

TPS next.

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This probably doesn't apply to either of you, but I wanted to include it for anyone that finds this thread in the future.

If the truck stalls when applying the brakes, it could be a vacuum leak in the big vacuum tube running to the brake booster.

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I was having the same high idle issues. After stalling, when I started it back up the rpms would soar. I just adjusted the TPS last week. It was putting out around .4 - .5 volts at the idle position. The voltage increase as the throttle was opened up was very smooth and steady. I increased the jamminz.gif voltage at idle to .8. Now everything seems fine. No stalling and smooth idle. What surprised me is how far I had to move it in order to get it right.

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  • 1 month later...

OK, well I finally got this fixed. What I did was clean the the throttle body by removing it and taking both sensors off. I cleaned every hole and orifice ;) with carb cleaner and paper towels. I used almost a whole can and cleaned it up really good. When I took the TPS off, I didn't notice how it was set, and had to adjust by repeated trial and error. It took about 20 times of loosening and tightening the sensor and moving it a tiny bit until it would run well. I don't have a volt meter so I had to do it this way. I will have one to use tomorrow and will adjust it the right way.

Regardless, the RPMs never drop below 1K now! W/ the meter, I can set the TPS so it idles a little slower and runs a little smoother. I don't know which one helped more, the TPS adjustment or cleaning the T body, but it works much better now. My guess is the TPS adjustment is what helped the most. Anyway, thought I would let everyone know the problem seems to be fixed! :D

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My 90 MJ has been doing this periodically over the last few months but I'm fairly sure that it's the TPS, I have changed the IAC, and tested the EGR circuit.

Does your truck do it all of the time? Some days mine will run fine then the next day it will stall almost everytime the clutch is pushed in when stopping.

 

But I am also starting to get high idle issues sometimes I come to a stop and the idle will be 1200 to 1800 rpm. This is why I'm going to replace the

TPS next.

 

Not sure if u have done this yet, but try just adjusting it first. There is a great article at jeepforums.com in the cherokee tech FAQ on how to do it. IT may be in this forum too, but I saw it over there for sure. It will go a lot faster/more accurate with a voltmeter.

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My 90 seems to be suffering the same thing as described above. The first thing I did was remove the vacuum lines from the 2 port output of the EGR solenoid. This seemed to kick the idle back up. I have been running it for 2 days with that vacuum line off, and there have been no instances of it almost dying when pushing the clutch in at a stop. Could I have a bad ERG solenoid? Vacuum routing issues? I'll need to check everything in the vacuum system to rule that out. What if it is a bad solenoid? I can't seem to find one online at any of the major websites...dealer only?

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My 90 seems to be suffering the same thing as described above. The first thing I did was remove the vacuum lines from the 2 port output of the EGR solenoid. This seemed to kick the idle back up. I have been running it for 2 days with that vacuum line off, and there have been no instances of it almost dying when pushing the clutch in at a stop. Could I have a bad ERG solenoid? Vacuum routing issues? I'll need to check everything in the vacuum system to rule that out. What if it is a bad solenoid? I can't seem to find one online at any of the major websites...dealer only?
I would be suspicious of the EGR solenoid. At idle there should be no vacuum going through that solenoid, but it sounds like it may staying open and activating the EGR valve at idle which will cause low idle or stalling. The EGR solenoid should only open at RPM's over 1500 according to the FSM.
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Should I replace it? If so, where the heck can I get one?
Obviously I can't tell you to replace it from here, but if you feel that you want/need to...the part # is 33002298 if you want to check a dealership near you or I can get you one for $65 shipped :cheers:

 

EGR Solenoid Test per the FSM

 

1) Verify that vacuum is present at vacuum fitting "C" of

EGR solenoid. See Fig. 4. Remove vacuum connector from "A" and "B".

Connect a vacuum gauge to "B".

 

2) Start and idle engine. There should be no vacuum at "B".

Disconnect electrical connector "D" from solenoid. There should now

be vacuum at "B".

 

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Be sure and take the part # with you if you need to go so they don't have to "deal" with it :roll: . Don't let them tell you they can't get it either as there are still 158 of them in the National warehouse ;)

 

OH...I probably shouldn't have, but I have been ASSuming in all of this that you have a 4.0L in yours... :chillin:

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My 90 MJ has been doing this periodically over the last few months but I'm fairly sure that it's the TPS, I have changed the IAC, and tested the EGR circuit.

Does your truck do it all of the time? Some days mine will run fine then the next day it will stall almost everytime the clutch is pushed in when stopping.

 

But I am also starting to get high idle issues sometimes I come to a stop and the idle will be 1200 to 1800 rpm. This is why I'm going to replace the

TPS next.

 

This explains my problem word for word!!! Ive been trying to fix this for the past 3 mos, but the stall issue is just now starting. So far I've replaced the map,mat,iac,cts,and egr. was going to find a cheapo tps at the pick and pull yard, but all had been taken. So I guess its off to Napa to get a new one.

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