Morning.
2000 Jeep Wrangler Federal emissions MT 136,000 miles. Factory stock.
I have spent several days on and off of this forum and have learned a great deal about the issues that TJ owners suffer.
Here’s mine. Last week I was driving no issues. Stopped by the parts store picked up an oil change and some plugs (have been using O.E. Champions since I bought it in 2000)
Got home changed the oil and plugs, buttoned everything back up cleaned up, hopped in to run an errand and it started then died before I could pull away from the curb. Ok, restarted just fine then I pulled out and got headed on my way then it died a short time later. Cycled the key and it started up but would die shortly after. Rinse and repeated this process limping it home.
No CEL, no codes.
Dug into diagnostics (ASE Master tech retired) retraced my steps with the tune up, unplugged coil rail checked for 5v, at coil good. Checked continuity on driver circuits and ground good. Plugged it back in. Turned it over fired right up and idled for about 10 mins then died. Was acting like it was starving for fuel. Checked pressure at rail as it sat, 50 psi. Started engine again after 5 or so minutes, was able to get a couple wot snaps in before it died, psi ranged from 50 idle down to 47 at wot.
Then, I turned to the forums here found out that the ckp is a super common fail point even without codes. Ordered one from Napa. While I waited for it to arrive I checked all the wiring. Continuity on all the wires to the pin at pcm. No excessive resistance found, what I would consider normal. Plugged sensor back in tried to get it to run long enough to run a scope but it wouldn’t stay running more than a couple seconds at this point. Got the new sensor and installed it. Fired right up and was able to drive it for about a day and around 40 ish miles. Problem resurfaced. This time however I had confirmed codes stored
IGN coil #1 2 and 3 fault
No ckp signal at pcm
Ok, the coil was OE I never changed it. So I ordered a new coil and warrantied the crank sensor. Rechecked the wiring. Everything checked out.
Installed the coil and replacement sensor rechecked the wiring, started it up and a new symptom appeared.
Runs but cuts out intermittently like the key was switched off, the tach bounced up and down randomly jumping from idle to 2500 back to 1700 back to idle while the engine stumbled and then eventually died.
I also observed that my oil pressure gauge pegged to 80 and stayed there 0 fluctuation, and my scan tool would lose communication with the PCM while it was sputtering and the gauges were acting oddly. So back to square one. This time I pulled the harness and exposed all of the wiring. Gotta be a broken wire making intermittent contact or a shorted groung splice or a chaffed wire. Nope harness looks pristine, no rub through, no broken wires every sensor wire check out with continuity at the pcm pin. Pulled all the grounds and cleaned them (they all were pretty clean to begin with) Battery cables are clean and tight. Battery is in good health.
Checked the CPS had a good wave form on signal with scope.
Let it sit over night came out it started and ran like a champ until it got to around 150 degrees then it started acting up again, same symptoms: rough/erratic idle, sputtering, drop outs with recovery, gauges acting weird and this time I had confirmed codes stored again. Ign coil 1 2 3 fault and this time no cam sensor reference. So i replaced the cam sensor. Didn't solve the issue.
Its now doing the smae thing but I again have the loss of coms with my scan tool.
Heres a snapshot of what I've done:
Replaced crank sensor
Coil and plugs
Replaced cam sensor
Run wiring multiple times can not find a fault there
checked for power and ground at PCM pins (back probed) while running no drops on 12V or ground.
Reseated PCM plugs
Checked and cleaned all grounds.
checked alternator ripple is steady.
down stream ) is a little sluggish but still reading (shouldn't cause loss of coms or drop outs)
Checked injector driver signal with my noid lights no issues there.
EDIT:
Forgot to add that I've cleaned the throttle body and the IAC motor.
PCM?????
I've investigated potential causes for from this forum and found there to be no issues present. but the problem persists. at this point it has moved from intermittent to full failure as it has moved into crank no start. no codes are present.
Side notes:
I get that everyone advises going with mopar parts especially for the CKP. however, this is my daily driver and the only vehicle I own. the closest dealership is 28 miles away so thats not an option for me, I have searched for online options for these parts to no avail. I've been an repair tech for 27 years and have used aftermarket parts for this issue from other jeeps during that time and not had issues. I also state that not to be arrogant but to let you guys know i'm not a shade tree and you can talk pro level shop with me about this situation.
I'm pretty solid with drive ability and diagnostics and I'm completely stumped.
Any help is appreciated.
2000 Jeep Wrangler Federal emissions MT 136,000 miles. Factory stock.
I have spent several days on and off of this forum and have learned a great deal about the issues that TJ owners suffer.
Here’s mine. Last week I was driving no issues. Stopped by the parts store picked up an oil change and some plugs (have been using O.E. Champions since I bought it in 2000)
Got home changed the oil and plugs, buttoned everything back up cleaned up, hopped in to run an errand and it started then died before I could pull away from the curb. Ok, restarted just fine then I pulled out and got headed on my way then it died a short time later. Cycled the key and it started up but would die shortly after. Rinse and repeated this process limping it home.
No CEL, no codes.
Dug into diagnostics (ASE Master tech retired) retraced my steps with the tune up, unplugged coil rail checked for 5v, at coil good. Checked continuity on driver circuits and ground good. Plugged it back in. Turned it over fired right up and idled for about 10 mins then died. Was acting like it was starving for fuel. Checked pressure at rail as it sat, 50 psi. Started engine again after 5 or so minutes, was able to get a couple wot snaps in before it died, psi ranged from 50 idle down to 47 at wot.
Then, I turned to the forums here found out that the ckp is a super common fail point even without codes. Ordered one from Napa. While I waited for it to arrive I checked all the wiring. Continuity on all the wires to the pin at pcm. No excessive resistance found, what I would consider normal. Plugged sensor back in tried to get it to run long enough to run a scope but it wouldn’t stay running more than a couple seconds at this point. Got the new sensor and installed it. Fired right up and was able to drive it for about a day and around 40 ish miles. Problem resurfaced. This time however I had confirmed codes stored
IGN coil #1 2 and 3 fault
No ckp signal at pcm
Ok, the coil was OE I never changed it. So I ordered a new coil and warrantied the crank sensor. Rechecked the wiring. Everything checked out.
Installed the coil and replacement sensor rechecked the wiring, started it up and a new symptom appeared.
Runs but cuts out intermittently like the key was switched off, the tach bounced up and down randomly jumping from idle to 2500 back to 1700 back to idle while the engine stumbled and then eventually died.
I also observed that my oil pressure gauge pegged to 80 and stayed there 0 fluctuation, and my scan tool would lose communication with the PCM while it was sputtering and the gauges were acting oddly. So back to square one. This time I pulled the harness and exposed all of the wiring. Gotta be a broken wire making intermittent contact or a shorted groung splice or a chaffed wire. Nope harness looks pristine, no rub through, no broken wires every sensor wire check out with continuity at the pcm pin. Pulled all the grounds and cleaned them (they all were pretty clean to begin with) Battery cables are clean and tight. Battery is in good health.
Checked the CPS had a good wave form on signal with scope.
Let it sit over night came out it started and ran like a champ until it got to around 150 degrees then it started acting up again, same symptoms: rough/erratic idle, sputtering, drop outs with recovery, gauges acting weird and this time I had confirmed codes stored again. Ign coil 1 2 3 fault and this time no cam sensor reference. So i replaced the cam sensor. Didn't solve the issue.
Its now doing the smae thing but I again have the loss of coms with my scan tool.
Heres a snapshot of what I've done:
Replaced crank sensor
Coil and plugs
Replaced cam sensor
Run wiring multiple times can not find a fault there
checked for power and ground at PCM pins (back probed) while running no drops on 12V or ground.
Reseated PCM plugs
Checked and cleaned all grounds.
checked alternator ripple is steady.
down stream ) is a little sluggish but still reading (shouldn't cause loss of coms or drop outs)
Checked injector driver signal with my noid lights no issues there.
EDIT:
Forgot to add that I've cleaned the throttle body and the IAC motor.
PCM?????
I've investigated potential causes for from this forum and found there to be no issues present. but the problem persists. at this point it has moved from intermittent to full failure as it has moved into crank no start. no codes are present.
Side notes:
I get that everyone advises going with mopar parts especially for the CKP. however, this is my daily driver and the only vehicle I own. the closest dealership is 28 miles away so thats not an option for me, I have searched for online options for these parts to no avail. I've been an repair tech for 27 years and have used aftermarket parts for this issue from other jeeps during that time and not had issues. I also state that not to be arrogant but to let you guys know i'm not a shade tree and you can talk pro level shop with me about this situation.
I'm pretty solid with drive ability and diagnostics and I'm completely stumped.
Any help is appreciated.
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