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Discussion Starter · #1 ·
Helping my in laws work on their jeep. 2000 TJ manual trans ~180k miles. When I borrowed it a few years ago, never had an issue. But recently you'd be driving and randomly rain or shine, the engine would cut out, then start back in. Feels like the cutch was pushed, then let go, so you feel a jerk. All the lights and radio etc stay on.

I check the voltage of battery, seems fine, and alternator was replaced (looks replaced) a while ago.

I did suggest the battery cables be upgraded. So we did that from custombatterycables.com . then for the next couple days it didn't do it, but now its back to doing it.

From reading around, it may be a ground (another spot to look under hood / behind engine), tub and rear of jeep. PCM could be going (see a lot of those, but man they want $600), maybe? the crank or cam shaft sensor?

Any thoughts or tips?
 

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Sounds like the crankshaft position sensor (CPS) is failing to me.
 

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What code was produced?
Several auto parts stores will read them for free if you don’t have a reader.
 

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Doesn’t sound quite like what I experienced, so unlikely the same cause, but I had severe stalling issues that ultimately after replacing every sensor came down to overheated fuel injectors. Specifically cylinder 3 on the straight 6 was roasting the fuel a bit early.

I replaced my injectors and added heat shielding.

I was warned early in the process not to rely on aftermarket sensors, so I’d suggest getting MOPAR parts if you need to replace any.
 

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Discussion Starter · #7 ·
Doesn’t sound quite like what I experienced, so unlikely the same cause, but I had severe stalling issues that ultimately after replacing every sensor came down to overheated fuel injectors. Specifically cylinder 3 on the straight 6 was roasting the fuel a bit early.

I replaced my injectors and added heat shielding.

I was warned early in the process not to rely on aftermarket sensors, so I’d suggest getting MOPAR parts if you need to replace any.


Good thinking! Yup? I ordered mopar cps from rock auto. Came on Monday but waiting for our schedules to align and get it installed.

How did you know or figure out it was an injector? Did your Jeep throw a code?
 

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I did at one point have some misfires that resulted in a code if I recall correctly, but it was a combination of visual inspection and elimination of everything else that finally did it.

Seriously, I replaced the coil, upgraded the spark plugs, replaced every sensor (some of them twice), replaced the OPDA...and then we noticed that the injectors looked filthy.

In my defense, I don’t know shit about engines (or really anything automotive), was relying on mechanics to help me out. I was just desperate to stop stalling in the middle of the road; I got pretty good at turning it off and re-starting it at speed, but eventually it got so bad it wouldn’t start back up again.
 

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Discussion Starter · #9 ·
I did at one point have some misfires that resulted in a code if I recall correctly, but it was a combination of visual inspection and elimination of everything else that finally did it.

Seriously, I replaced the coil, upgraded the spark plugs, replaced every sensor (some of them twice), replaced the OPDA...and then we noticed that the injectors looked filthy.

In my defense, I don’t know shit about engines (or really anything automotive), was relying on mechanics to help me out. I was just desperate to stop stalling in the middle of the road; I got pretty good at turning it off and re-starting it at speed, but eventually it got so bad it wouldn’t start back up again.
That is the good part about a manual, is start/stop while driving. Man that sucks, I have never had to replace an injector on a car, on purpose. But this jeep has like 185k miles and the RMS is seeping etc, so it is kind of a filthy block. Hope it is something easy
 

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Discussion Starter · #10 ·
On the way to my house the Jeep didn’t shut off (15 min drive). I replaced the crank shaft position sensor. When she left it died twice on the way to the store :/

I see the two ground posts on the firewall. The drive side one was pretty tight. So I’ll have to penetrate that bolt and back it off to clean. The passenger side one I cleaned up when doing the batter cable kit. I heard there is another on the rear for the tub. I looked quick and couldn’t find it.

I’m gonna check the rear ground if I can find it, clean up the grounds. What else can anyone think of? She said every so often she has a cel, so a friend let her borrow a scan tool. She’ll read the cel next time it happens. I used my tool and it didn’t see any issue codes.
 

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Discussion Starter · #11 ·
Ordered a cam shaft position sensor (mopar brand). That will be in next week and I’ll put that in and see.
 

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Discussion Starter · #12 ·
Update.

Just installed the cam sensor, old one, was old but looked clean, so unless the Halifax sensor is bad, probably not it.

She had a cel, and was almost to work so she was going to read it, the tj did the engine shut off thing and the cel was gone, scanned the Jeep at work, no code. Almost have to log while driving....

Still can’t find rear tub ground, any tips?
 

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Discussion Starter · #13 ·
Just went on a 20mile ride with my odb mx plugged in. Nothing until mile 19, the car did the engine shutoff, felt like a big jerk, no cel. The quest continues, I may look at plugs and then injectors
 

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Discussion Starter · #14 ·
CEL finally popped last night. P0340

Replaced:
battery cables
Cam shaft position sensor (mopar)
Crank shaft position sensor (mopar)

Looking at:
Battery (currently installed is what looks to be an undersized everlast)
Coil pack (mopar)
Sparkplugs
Injectors
ECU
 

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P0340(M) No Cam Signal At PCM No fuel sync.


CHeck the cam sensor again. It needs 5 volts. It is not uncommon for the main wiring harness that feeds the CAM sensor to have broken or chaffed wires. I would pull the loom and inspect.



Dont order a PCM, it is highly unlikely that it is the cause of your issues.
 
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Discussion Starter · #16 ·
P0340(M) No Cam Signal At PCM No fuel sync.


CHeck the cam sensor again. It needs 5 volts. It is not uncommon for the main wiring harness that feeds the CAM sensor to have broken or chaffed wires. I would pull the loom and inspect.



Dont order a PCM, it is highly unlikely that it is the cause of your issues.
Oh, for sure the PCM is not just an order for fun part. I'll check voltage and continuity of the cam sensor.

I was going to take the connectors off the PCM, inspect and clean too.

The google'foo I've done however this is a common issue and solutions range from a sensor to xyz parts.
 

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I had no-start/random dying issue a few years ago that took me forever to find. Long story short, the plugs at the PCM had somehow become unseated enough to cause the loss of signal to the CAM and CPS sensor. I suspect this could be your issue or a damaged wire or two within the wiring loom.
 

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To find the tub ground look at underside of hood at hinge end
There should be a ground strap bolted to hood
Follow that ground strap from hood to attachment on firewall
That same bolt with firewall to hood ground should have another ground that runs from that bolt to top rear of engine (this is the tub ground strap)


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Discussion Starter · #19 ·
I had no-start/random dying issue a few years ago that took me forever to find. Long story short, the plugs at the PCM had somehow become unseated enough to cause the loss of signal to the CAM and CPS sensor. I suspect this could be your issue or a damaged wire or two within the wiring loom.
I'll be doing this soon, this week I hope.
 

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Discussion Starter · #20 ·
To find the tub ground look at underside of hood at hinge end
There should be a ground strap bolted to hood
Follow that ground strap from hood to attachment on firewall
That same bolt with firewall to hood ground should have another ground that runs from that bolt to top rear of engine (this is the tub ground strap)


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Thanks. I'll check that ground and make sure the strap to the engine is still there.
I thought I read a thread similar that they found a ground strap in the rear was broke and hitting the exhaust. But I was under the rig and couldn't find a rear ground strap.
 
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