stalling jeep

Hello all , I need a little advice. I own a 1994 Jeep grand cherokee laredo with a straight 6 in it.It has 194,000 miles on it I have not had any problems with it other then routine maintenance but In the last month it has started stalling. Sometimes i will be going 60mph sometimes i will be going 20mph , The rpm's just drop out , sometimes it will go back up without stalling but 9 times out of 10 it will just drop and stall , after it stalls sometimes it will start right back up , sometimes it will not. sometimes it will start right up in the morning after sitting all night and sometimes it won't start. It has been given a full tuneup(oil change, new plugs,wires,cap,rotare) The fuel pump is working , it has been to the shop and the guy cleaned out a valve but it is still doing it. I am very frustrated because all of my gauges are fine , my computer isn't telling me anything and my check engine light is not comeing on at all.........HELP ME PLEASE!!!!!!!!!!

I just had this same problem on my '94 Jeep GC (6 cyl.) and replaced the CRANKSHAFT POSITION SENSOR (CPS). My Jeep had the same exact symptoms that you described.

If you want to do it yourself it's pretty easy (once you know how). I bought the part at www.rockauto.com for about $55. It's also a standard stock item at Autozone (about $65). The Jeep dealer sells it for $90, but I didn't need a genuine Jeep part.

This solved the problem and I haven't had any stalling since I replaced it about 6 weeks ago.

Write back if you want guidance on replacing this yourself, or if you're having a shop do it, be sure the price is reasonable, given that the part is around $60.

Same prob with my '97 JGC limited. Although it never happened at high rpm's. Only when approaching or sitting at a stop sign. Anyways, it is only 2 bolts (1/2") and an electrical connector located on the transmission bell housing directly behind the RH valve cover. You can see it from below, but access it from above. You cannot see what you are doing so it makes it a pain in the butt. Just remember how much $$ you are saving by doing it yourself. You might wanna buy the part first so you know what you're looking for, cuz it is kinda hard to see. Good luck!

Kranky :grinyes:

The CPS is slightly different on the '94. There's only one bolt on the '94 sensor, and I found it easier to access from underneath. That was only after I found the bolt from the top and aimed a bright work light on it. Then with about a 16" socket extender I got a socket on it pretty easily (I think 7/16" socket). Then I unhooked the plug and reconnected the new one from the top.
On my first attempt I looked for it for about an hour then postponed the project. When I finally got the determination to get the job done, it took only 20 minutes, including cleaning grease off my arms, from reaching half-way through the engine compartment. It's do-able.
Let us know how it goes!

I have a '93 Cheroke, 6 cyl (140,000 miles) with what sounds like EXACTLY the same problem. I went through a Full tune up, Injection cleaning, and from the Jeep dealer a $90 diag that said that the problem was an Ignition coil. That last item's total cost was $201.00 (including the diag). And I still have the same problem. I will go back to the dealer, but do you think this is the same fix as what is being reported here on the Grand Cheroke's? Wish me luck on getting my previous repair credited towards this one!!!

Thanks,
too much in debt and frustration.

It most definitely is your crankshaft position sensor. mine went out and it took all of 20 minutes to replace. its located on top of your transmission at the 11:00 position right under the firewall and is very hard to unscrew if you have big hands. hope this helped!

I'm surprised how many dealers and service centers are unaware of how to properly diagnose the stalling problem. Perhaps they don't do much work on 10-year old Jeeps. I had two dealers refuse to even take a guess at the problem over the phone (or even comment on the likelyhood that it's the CPS), and suggested I pay their diagnostic fee to check it out.

I've found this Forum to be the best way to get a lot of input on problems without spending money. I agree with Inkmonki's posting above - it took me 20 minutes to replace the CPS, which cost about $60 at www.rockauto.com or Autozone. Diagnostics would have cost more than that, so I didn't hesitate to replace the part.
I'm done paying someone to repair things that I can replace myself - even if it means asking a ton of questions and buying a few tools. So far, this forum has saved me from going elsewhere.

Thanks everyone! Keep up the great work!
- JeepForever

Thanks to Inkmonki's and JeepForever's postings, I'll will see about doing the CPS. Catch this story:

I had already done a tuneup (wires, plugs, distributor cap, rotor, etc), fuel filter, Injection cleaning and some other front-end work.
Problem persisted, then I had that expensive Diagnostics ($90) that showed a bad Ignition Coil...(they replaced that) total cost was about $200. Problem persisted, then I had them take the car back and try to figure out what was wrong (no cost to me). I gave them copies of some of these postings showing the CPS and TPS. And I explained that if their mechanic could not find anything, to replace the CPS anyway. So I got a call back saying that they could not find anything except for maybe the Distributor having too much play. Estimated part cost was $400~ something and 1/12 hours labor (about $600 to $650 total). They would NOT guarentee that it would fix the problem. I asked why they did not replace the CPS, they said that they could not find anything wrong with it. (They also said the the CPS & TPS were the same thing!!!) I don't think so! Anyway, I told them to put it back together and I'll wait until it breaks. Now for my real feeling, I am going to buy that CPS and try to put it on myself. I'm not very handy with auto repair, but I'll try. I'm probably better than where I took my Jeep to, (An Authorized Jeep Dealer!) Thanks for the replies... This is a great site.

Perkinsrbp,

I commend you on your desire to repair the CPS yourself. As I mentioned in a prior posting, the CPS cost less than diagnostics, so I thought it was worth a try. Here are a few tips that will make your job easier (NOTE: I have a '94 Jeep GC, 6 cyl - I'm not positive the '93 is the same, but here's what I did):
1. Purchase the CPS (Autozone or www.rockauto.com both had them readily available - I wasn't name-brand picky, so I went with an inexpensive one).
2. Drive the front wheels onto ramps if you have them - this will give you room to get under the vehicle.
3. Open the hood, look on the right side of the engine as you're facing the windshield. About half-way down the engine on the bell housing of the transmission (close to the firewall) you'll see a wire connected. This is the CPS. On the '94 the wire drapes over the transmission behind the engine and plugs in on the LEFT side of the engine.
3. From the top, shine a bright work light on the CPS so you can see the bolt.
4. From underneath the vehicle, you can get to the bolt with a long socket wrench extension (I hooked all my extensions together to make it about 16 inches long. This allowed me to reach past the axle & other stuff). I think it's a 7/16" bolt.
5. Unscrew the bolt, reach up with one hand (no room for two hands), pull the little sensor out, put the new one in, screw it in until it's snug (don't over-crank it since it's a plastic sensor)
6. Plug in the new sensor wire
7. Start the vehicle, smile, and go for a test drive!
8. Clean all the grease off your arms.
9. Celebrate - you're smarter than an experienced auto mechanic!
Let us know how it goes!
- JeepForever

actually, the sensor on the 94 regular chero just slides into place freely and there are two screws on the left and right of it right on the trans bell housing, those are the only things holdin it in place. and of course you have that one wire to unplug. great step by step though!! :bananasmi

Status Update:
It's been about 1 1/2 weeks since I last communicated. But it's good news this time!

Again, Thanks to Inkmonki's and JeepForever's postings, They were right about my problem being the CPS.

I'm not mechanically inclined (sort of a computer nerd) so I gave in and talked to an old fashioned GAS station that actually fixes cars too! This was a family owned business since 1947 in NJ. I started asking the owner about my problem and he interrupted me and told me the story of my problem as if he had just been through it. Then he asked the magic question: Did anyone suggest or replace the CPS? BANG, Right-on... He did it the next day for about $150. (the part on a '93 Cherokee is more expensive, I priced it at the local parts store for $96.00). And we have been running for over a week without a problem.

He said that there are SO Many Jeep problems just like mine, and he doesn't understand why the Dealers don't or won't replace that darn CPS??? anyway, I'm fixed and many thanks to everyone on this site that either suggested or wrote about their problems.

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The reason why? $$ they want to rip you off. Pay for diagnosis, replace coils, rotors caps, wires jack the price up further. Canadian Tire is really bad for this, because their front-end people get commission.

Another common symptom is loose ground wires, that causes alot of problems.

Had a similar problem whenever I took my foot off the gas, at idle or at 60 mph. Try the Idle Air Control Valve. It allows air around the throttle plate at idle and maintains your lowest engine rpm. If this is bad, then it can't open or close fast enough, and the engine dies. I think I got a new one for $40-50 and it took about 10 minutes to change out. Real easy on top of the engine.

i had the same prob and i have replace the cps aic tps and it still stalls what do you think it can be? it happens while i am driving or when i am idleing mine is a 98 jgc and i can't figure out what it could be for the life of me.

did you disconnect the battery when replacing these electrical components.

no i didn't but i did not hook them up to the plug until i was finished. what happens if you put them in with the battery still hooked up?

Whenever you replace an electrical component the battery needs to be reset, either by disconnecting the battery before replacing the component or taking it to the dealership to have them reinitialize the computer. and disconnecting the battery afterward to attempt to reset it will not work, you will either have to replace the component again (remembering to d/c the battery befre removing) or take the jeep to the dealership to have them reinitialize the computer.

ok i understand what you are saying now. well when i hooked up the tps the check engine light turned off. I was looking at the plugs that go into the ecu or ecm and when i move them like a centemeter the car hesitates and if i do not move it back they car will stall kinda of like what it does when i drive it or just let it idle by itself . another question how much roughly would it cost to get my computer reprogramed. Is there a chance that my computer could have relearned it by its self because the check engine like was on until i turned it off and on a few times and it went out. another thing is that as soon as i got the tps installed my jeep took a few times to turnover but it did and it ran good until it stalled after ildeing for a good 10 mins. what do you think?

when you played aroudn with the connector at the PCM the jeep shuttered?

Check the wiring at the PCM, you might have a broken wire there, you will have to remove the black cover over the wires. I had a couple problems with a broken wire here, just a few months ago I had a problem with one of the wires going to the PCM (from the O2 Sensor) and my CHECK ENGINE light kept coming on after the jeep would reach normal operating temp and the code was for the O2 Sensor and I traced it back and found the wire was broken right where it enters the PCM connector.

Also check to make sure the 8mm bolt is tight. It should be snug not too tight

do you think this could be the stalling problem. i will be sure to do that. i did the home diagnostics and before we replace the tps the code was coming up and high and low voltage to the tps or somthing along those lines the code was 123 122

which bolt are you talking about

should i unplug the wires from the ecm first or sholdn't i do that

Have you checked for codes since replacing the TPS?

The bolt in the center of the PCM connector. The PCM is located on the passengerside firewall in the engine compartment, behind the coolant overflow bottle.

yes i did and it was saying 505 throttle malfunction somthing like that but i have not checked it in a few days the light hasn't come on if thats what you are asking

i will check on the bolt is that bolt like a ground or somting yeah i know the the ecm is located

No the bolt is not a ground, it actually just holds the connector tight to the computer. If it is not tight, then disconnect the battery, unbolt the connector from the computer, then remove the black protective cover and look for any broken wire.

You might want to remove the coolant overflow bottle, it iwll make getting to the PCM easier.

i will be sure to check that out and this time i will take the terminals are off to make sure i do not unset anything. i appreciate the help i am logging off i will keep you updated on the out come talk to you later

also, code P0505 - Idle AIr Control Motor Circuit. A shorted or open condition detected in one or more of the idle air control motor (valve) circuit.

This could be the cause of that shutter you got when playing with the PCM Connector, I think the problem might be a problem with the wiring going to the IAC Valve. When your stalling occurs does it happen at closed throttle or while pushing on the gas?

it happens during both pressing on the gas and when it is closed i am not sure if it still reading the 505 code anymore i will get the diagnostic tool from my friend again and i will see what it is telling me.

I had mine to the dealer 3 times, but when I asked them to replace the CPS, they refused. AN old time gas station that works on cars!, stopped me in my explanation of my problem and asked if I had the CPS replaced??? NO! They did it and it fixed the problem.

I have the same stalling problem in a 96 Grand Cherokee with the straight 6. I took it to a guy and he charged me $300 to replace the IAC, and it is still stalling. It actually stalled out 13 times the other day over a 2 hour drive. Driving me crazy. I guess I'll replace the CPS and hope that fixes it. Any simpler things I should try first?

When you replace the CPS, do not use BORG WARNER brand CPS and remember to disconnect the Battery before removing/replacing the CPS.

i had the same prob and i have replace the cps aic tps and it still stalls what do you think it can be? it happens while i am driving or when i am idleing mine is a 98 jgc and i can't figure out what it could be for the life of me.
I have the same problem with my 98 JGC. Did you figure out what was causing yours to do it after replacing cps, aic and tps?

I have the same problem with my 98 JGC. Did you figure out what was causing yours to do it after replacing cps, aic and tps?

It's been FINE since the CPS was replaced. I do not know how it was replaced (disconnect the battery?) and I do not know what brand, but it WORKS now! No Stalling...I had an old time gas (service) station do it. See previous postings...It cost about $145 (parts & labor)...I'm happy... The Jeep dealers are totally worthless!!! Even after I asked them to replace the CPS, they refused and wanted to replace other parts that would cost up to $600 or so...

To perkinsrbp,
Thank you for the assurance regarding the CPS. I've been watching the threads on this post and I saw yours was the same year of JGC as mine so it caught my attention. I am going to order a CPS and change it out myself. I was told by the shop that there was nothing they could do about it to fix it because they couldn't get the computer to tell them what it was. I can understand your frustration with the dealerships, although I am not a 'computer nerd' - I'm a GIRL! (which might be worse, but I'm not afraid to tear apart my car). Kind regards, CC

To perkinsrbp,
Thank you for the assurance regarding the CPS. I've been watching the threads on this post and I saw yours was the same year of JGC as mine so it caught my attention. I am going to order a CPS and change it out myself. I was told by the shop that there was nothing they could do about it to fix it because they couldn't get the computer to tell them what it was. I can understand your frustration with the dealerships, although I am not a 'computer nerd' - I'm a GIRL! (which might be worse, but I'm not afraid to tear apart my car). Kind regards, CC

Take care if you are doing this yourself...read all of the postings related to CPS's...they warn about disconnecting the battery and also having 2 people to change it...I think it is not easy to see and you have to be under the car and have someone direct you from above the engine (with a flashlight...). Oh, and I think it is a 30-45 minute job. GOOD LUCK! And I think it's neat that you are a girl and doing this yourself, my daughter changes flats and spark plugs herself.

Bye!