Wife's 1992 Cherokee 4.0L Just Quits - Help!

[GregA]

My wife's 1992 (about 118K miles) has developed a nasty symptom - it "Just Quit" when she was driving it today and it did the same thing while running in the driveway just now. No sputtering or rough idle - just quits (turns off). It will start back up again, but I don't want her driving around with this problem.

While poking around, I noticed an "Auto Shutdown" relay under the hood. Any idea about the CONDITIONS that might make this thing turn off?

The only things I noticed is that coolant recovery bottle was nearly empty while it was running, and that the aux fan was running while the Jeep was running in the driveway, but there was only relatively cool air coming toward the engine compartment. When I ran the idle speed up to about 1500 RPM, the air got hot. Possibly low on coolant? (I wasn't gonna try to open the radiator cap while hot). Could this cause the shutdown?

A couple of other previous symptom:
- The Jeep has been idling low (about 400-500 RPM) for some time. Used to stall out at a stop, but it has stayed running for at least six months with this condition.
- My wife reported a "shifting problem" just yesterday. Seems that it would not want to shift at the right point (long time to shift between gears).

Any insight would be appreciated.

Thanks in advance,

[Dale Aeppli]

Originally Posted by GregA

My wife's 1992 (about 118K miles) has developed a nasty symptom - it "Just Quit" when she was driving it today and it did the same thing while running in the driveway just now. No sputtering or rough idle - just quits (turns off). It will start back up again, but I don't want her driving around with this problem.

While poking around, I noticed an "Auto Shutdown" relay under the hood. Any idea about the CONDITIONS that might make this thing turn off?

The only things I noticed is that coolant recovery bottle was nearly empty while it was running, and that the aux fan was running while the Jeep was running in the driveway, but there was only relatively cool air coming toward the engine compartment. When I ran the idle speed up to about 1500 RPM, the air got hot. Possibly low on coolant? (I wasn't gonna try to open the radiator cap while hot). Could this cause the shutdown?

A couple of other previous symptom:
- The Jeep has been idling low (about 400-500 RPM) for some time. Used to stall out at a stop, but it has stayed running for at least six months with this condition.
- My wife reported a "shifting problem" just yesterday. Seems that it would not want to shift at the right point (long time to shift between gears).

Any insight would be appreciated.

Thanks in advance,

It sounds like you may have a crankshaft sensor probem , on the stalling When they start to go it will just quit running anytime ,anywhere. It will usually start right back up. When it goes it will crank but not start. The ASD relay is in case you wreck or roll-over it shuts the fuel and electrical system down, in case of fire. The low idle and shift problem maybe the throttle position sensor, it senses throttle position and sends enpulses to transmission for shifts, it also controls idle. [email protected] Dale

[GregA]

Originally Posted by Dale Aeppli

It sounds like you may have a crankshaft sensor probem , on the stalling When they start to go it will just quit running anytime ,anywhere. It will usually start right back up. When it goes it will crank but not start. The ASD relay is in case you wreck or roll-over it shuts the fuel and electrical system down, in case of fire. The low idle and shift problem maybe the throttle position sensor, it senses throttle position and sends enpulses to transmission for shifts, it also controls idle. [email protected] Dale

Thanks Dale. The CPS is next on my list. But here is what has been done so far.

Took the car to my "Trusted Mechanic" this morning and explained the issue(s). He took it for a test drive and did NOT have any problems. He did clean up the battery connections & recommended that the cables be replaced (corrosion INSIDE the cable near the connectors - will do sometime next week), and cleaned the throttle body. He also tested the fuel pressure and spark and said they were working fine. I don't remember him mentioning the CPS, but he may have tested that.

Idle is now back up to somewhere around 800 RPM after warmup. I have had it do this in the past, after the battery is disconnected and then reconnected (resets computer?).

BUT ... When I jumped back in to drive it home, it died again right there in the parking lot. Started right back up & ran all the way home.

I was going to replace BOTH the Auto Shutdown & Fuel Pump relays (they work "together"), but the parts store only had one in stock. So ...

I replaced the Auto Shutdown Relay with the new one and swapped the Fuel Pump Relay with the Starter Relay (they are all the same). I figure the following:

- If the Auto Shutdown Relay was the problem - it is FIXED.
- If the Fuel Pump Relay is intermittent, the car won't start some time in the future. This is still not good but much better then having the car "quit" while driving.
- If none of these relays are going bad, the problem will return as before. Then it would probably be time to go for the CPS.

Anyway, I made the replacement & swap and then took it for a 15-20 minute test drive. It worked just fine with no sign of problems. I will let everyone know if other symptoms show up.

Take Care,

[GregA]

I took the Jeep for a ride this morning and guess what . . . It is STILL doing it (turning off) . So I guess my relay idea was wrong - Oh well.

But something else happened. It stalled twice. The first time it started right back up. The second time it would NOT start back up again, but at least I was backing into my driveway at the time.

Another good thing about it not starting - it generated a failure code. The code is 11, which the Haynes manual says is "No crank reference signal to computer" - Check connections between computer (PCM) and Crankshaft Position Sensor and replace CPS if needed.

I tested the voltages at the connector (over the intake manifold) and everything looks OK coming from the computer. So I suspect the CPS (recommended by Dale) and got one from the parts store (about $60 with tax). The bad news - I don't have the right tools to get the job done (not enough extenders to get to the mounting bolts). So I will be taking it (or dragging it) down to the shop to get it replaced on Tuesday.

One more thing - it is still intermittent because when I was testing it for pulses (while cranking) it worked! Plugged the connector back in and it starts and runs again! I just hope it runs long enought to get it to the shop (about 3 miles away).

Wish me luck,

[GregA]

Originally Posted by GregA

- I don't have the right tools to get the job done (not enough extenders to get to the mounting bolts).

OK - I caved in yesterday and bought a set of wrench extensions (I guess I am stubburn - "I can fix this" is what I was thinking). And I "needed" the extra tools anyway.

So I changed the Crankcase Position Sensor. Took it for another test drive and it seems to be OK. But that happened before too.

So I will drive the Jeep for a couple of days and make sure the problem does not reappear while the wife drives the van. I will report back if this does NOT fix the problem.

Take Care & Happy 4th!

[robertjr]

yeah I would really like to know if that fixed problem because I am having a smiliar problem with my wifes cherokee.

[GregA]

Originally Posted by robertjr

yeah I would really like to know if that fixed problem because I am having a smiliar problem with my wifes cherokee.

I drove it a couple of times today and my wife drove it once. Still working!

One suggestion - check for codes (turn key from OFF to RUN 3 times within 5 seconds. Stop at RUN the third time - watch the check engine light for flashing patterns).

My Check Engine light did NOT come on any time during the initial problem. I only got the code 11 after it failed to start while cranking. That (& Dale's comment) led me to the CPS.

Take Care,

[Jspicer]

Originally Posted by GregA

I drove it a couple of times today and my wife drove it once. Still working!

One suggestion - check for codes (turn key from OFF to RUN 3 times within 5 seconds. Stop at RUN the third time - watch the check engine light for flashing patterns).

My Check Engine light did NOT come on any time during the initial problem. I only got the code 11 after it failed to start while cranking. That (& Dale's comment) led me to the CPS.

Take Care,

I'm dealing with this misfire problem on a 4.0L 98 . So far have replaced, battery,plugs, wires, the coil, Map Sensor, Cam Shaft Sensor, today the Crank Sensor. Still misfiring just before engine heats up to full temp, then runs fine. Next will be the TPS I suppose. No computer codes show, scanner tests al fine. Just passed emmisions test fine too. Three mechanics have looked and still no luck. Anyone want a Jeep CHEAP ?

[GregA]

Originally Posted by Jspicer

I'm dealing with this misfire problem on a 4.0L 98 . So far have replaced, battery,plugs, wires, the coil, Map Sensor, Cam Shaft Sensor, today the Crank Sensor. Still misfiring just before engine heats up to full temp, then runs fine. Next will be the TPS I suppose. No computer codes show, scanner tests al fine. Just passed emmisions test fine too. Three mechanics have looked and still no luck. Anyone want a Jeep CHEAP ?

If you can get it here, I will give you $20 for it! (Just kidding).

I think you need to find someone who is willing to do some "extensive troubleshooting" to find the problem. Someone with the experience and knowledge to go further than just waiting for a code to appear before trying to fix. It won't be free, but probably less expensive than changing parts and "hoping" that will fix it.

Good Luck,

PS. My wife drove the Jeep ('92 Cherokee) today and it still works. I think it is fixed!

[robertjr]

That great buddy good luck with your rig I got mine running and haven't had any problems in the last few days so I think I got it fixed as well.

[GregA]

Originally Posted by robertjr

That great buddy good luck with your rig I got mine running and haven't had any problems in the last few days so I think I got it fixed as well.

Too Cool

Was it the Crankshaft sensor or something else? Did you loose any skin fixin' it?

Take Care,

[robertjr]

yeah I replaced the CPS and I had to flush the fuel system replace the filter cause I think that I had water In the fuel but she's running like a champ now! and yeah I did lose some skin

[Jspicer]

Originally Posted by GregA

If you can get it here, I will give you $20 for it! (Just kidding).

I think you need to find someone who is willing to do some "extensive troubleshooting" to find the problem. Someone with the experience and knowledge to go further than just waiting for a code to appear before trying to fix. It won't be free, but probably less expensive than changing parts and "hoping" that will fix it.

Good Luck,

PS. My wife drove the Jeep ('92 Cherokee) today and it still works. I think it is fixed!

Now Jul 12, one week later. No sensors left to replace. All that remains is the ECM, onboard computer. Still has major misfire just before reaching operating temp. Never any codes. Mechanic took it home overnight and drove with diag comp attached. It acted up and nothing showed on either computer. Something is turning on and off rapidly and then smooths out perfectly. Searching junk yards for a used comp to try. One of the three mech has 15 yrs Chrysler exp. None have heard of this problem before. Any guesses welcome at this point. Thanks in adavance. JSpicer

[shado40]

My wife's jeep acted like that last year, would just shut down seemingly randomly. I fixed it by changing the resistor that sends to the fuel pump I think it costs like $3.50 or something, so for that price it might be worth a shot to try.

[Jspicer]

Originally Posted by shado40

My wife's jeep acted like that last year, would just shut down seemingly randomly. I fixed it by changing the resistor that sends to the fuel pump I think it costs like $3.50 or something, so for that price it might be worth a shot to try.

Well now the computer has been replaced and no difference. It doesn't shut down, just starts missing / backfiring but does manage to keep running. Its not random. Always does it 1 minute after starting cold or just before reaching operating temp if already warm. Does it once each outing adn runs perfect afterwards. Never sends a code. Seemingly nothing electricial left to replace. Never heard of valves or anything mechanicial doing this. Still unsolved !