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check engine light, feels like i lost a cyl

thewrath

NAXJA Forum User
Location
Nashville, TN
havnt posted in a while, but im just had a weird problem start this morning on my way to work. about half way through my 3 mile drive the check engine light came on and the engine began running kinda funny, like its running on 5 of 6 cyl or ignition timeing is way off or something. checked fluid levels and gauges all looks fine. checked to make sure injectors and plugs are all plugged in and tight. i also seem to have a 3kRPM rev limiter now. any gueses out there without having a scan tool?

2000 XJ Limited, 4.0, AW4, 242
 
went back out to the jeep, jiggled all injectors and injector wires again, started and it ran fine. no idea what it couldve been but check engine is still on. will get someone to read the code for me after work today.
 
thewrath said:
havnt posted in a while, but im just had a weird problem start this morning on my way to work. about half way through my 3 mile drive the check engine light came on and the engine began running kinda funny, like its running on 5 of 6 cyl or ignition timeing is way off or something. checked fluid levels and gauges all looks fine. checked to make sure injectors and plugs are all plugged in and tight. i also seem to have a 3kRPM rev limiter now. any gueses out there without having a scan tool?

2000 XJ Limited, 4.0, AW4, 242

I suspect the scan tool will report a misfire on such-and-such cylinder... and won't give any real clues. But it's certainly worth hooking it up. It will, at least, point to a particular cylinder to look at.

As for the 3k rev-limiter... I know that some Chrysler products (including the PT Cruiser, with a similar multi-coil ignition) have a rev-limiter that prevents over-revving an auto-tranny engine when out of gear. I can't say that I've really tried to rev my 2000 while sitting still...

All of these problems being reported with 2000 XJ's recently are beginning to worry me... :(
 
2002 sebring conv has lower rev limiter when in N or P, but not the XJ, itll rev pretty close to redline in N.

but back to the actual problem, the jeep wouldnt rev above 3k while driving around (or in N) when the problem was occuring. i had never heard of or seen this before . also the check engine light would flash occasionally as well. anyone ever heard of these two things happening on a XJ?
 
Not sure about this happening to an XJ but I had an MJ in '87 that had the occasional fits and starts (no power, stumbling at different speed, not reving, etc.) and it turned out to be a clogged Cat. The material in the convertred would occassionally shift, causing excessive back pressure to build in the exhaust, causing those gasses to build in the combustion chamber. Stopping and letting the Jeep cool had irregular effects. I tried everything I could think of at the time to diagnose/fix the problem. I finally took it to the dealer, paid $11 (ah, the good old days) for diagnosis and they replaced the Cat under the emissions warranty. I don't know if this is a known issue with the XJ, but emmission warranties I belive are supposed to be at least 5 yares and/or 80k (not exactly certain) and are not void unless you significantly alter the system. That's my $.02
 
P0203 Injector 3 Control Circuit
P0303 Cylinder 3 Misfire Detected

1-5-3-6-2-4 is the firing order

and from another thread langer1 says "If the CamPS in the distributor is not working the ECU will start the engine in an emergency operating mode, it won't run right but it will get you home."

so i think ive been running in this emergency operating mode at time due to the 3kRPM limiter.

but my question is, the code says cyl3, is this 3rd cyl back from front of car or 3rd cyl in firing order? i know in this case its the same, but i was just wondering.

also any ideas as to where to begin troubleshooting? not sure how to check injector or plug issues.
 
frankenjeep said:
i thought i read somewhere that a flashing check engin light means there are major problems ??


Flashing check-engine light means "catalytic converter damage is imminent".
Those are the ones you're supposed to park, and call the tow truck for.

However... the misfire is what was setting that code. The computer had (has!) no way of knowing WHY the engine is misfiring... but it assumes the worst (that raw fuel is being dumped to the cat).

It looks like the computer knows of an injector circuit problem. Could be a bad injector, or a bad connection, or a bad ground...

Den
 
Hi,

I have a 2000 Cherokee Sport that was doing the same thing, CEL flashing, code P0202, just running like total crap. The problem, in my case, was that one of the wires to the injector had shorted out. Here's how it works:

The wires to the injectors are HOT (+) and the ECU fires the injector by grounding the circuit. If the wire going TO the injector shorts, no fuel and it probably damages the ECU. If the wire AFTER the injector shorts, the injector is constantly open, engine runs like crap, mileage goes to crap, and you start getting misfire code on that cylinder. After so many misfires, engine goes into limp mode.

In my case, the wiring harness for the fuel injectors was rubbing against the fuel rail and it had cut through the plastic wrap and into the wires. Trace the injector wires up into that stupid aluminum deco cover and then out the back to the firewall.

Hope that helps.
 
in my case, was a bad injector. ran out of time to find parts and fix myself. autozone sold me an injector they said was the right one, but it looked completly different, and they didnt have any o-rings. ended up taking it to the stealership because i was going to be out of town for a few days, and they swaped the injector. autozone was charging 80$ and the stealership was charging 63$. amazing. not so much of a stealership. from now on i guess i start calling them for price quotes on parts. ended up costing 230$ with parts and labor and tax. also they didnt even try to sell me on 6 new injectors. not bad
 
Bringing an old post back up for something similar.

I have an 01 that is showing a multi cyl misfire on 1 and 3. Replaced the plugs. The #3 plug electrode was smashed down and almost touching the core. Replaced all the plugs but haven't cleared the code yet to see if that was the problem. Still doesn't seem to run good.

What else could cause a multi cyl misfire? Obviously not an injector problem.
 
i would still check out the injectors. I have now replaced 3 injectors on my 2000 XJ with 135k miles. I also have to cut back a chunk of the injector wires and splice in new lengths of cable and new electrical connectors on the end. since doing this i have had no misfire problems. fuel, spark, and air are all required. sounds like you got spark covered, and i would be surprised if there is no air getting in the cyl.
 
wasnt there a tsb about an injector heat soak issue on the 2000-01 models. a heat sheild needed to go between the injectors and the intake manifold.
 
DrMoab said:
Bringing an old post back up for something similar.

I have an 01 that is showing a multi cyl misfire on 1 and 3. Replaced the plugs. The #3 plug electrode was smashed down and almost touching the core. Replaced all the plugs but haven't cleared the code yet to see if that was the problem. Still doesn't seem to run good.

What else could cause a multi cyl misfire? Obviously not an injector problem.
Hey Doc did #3 look like anything hit it to smash it, that don't sound to good. I don't know how close the piston come to plug on 4.0, like GM's old Tech 4s if the timing belt slips the piston would hit a valve.
 
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i think there was at some point but i don't remember if it was specifically injector problems due to heat. I do remember having some heat shield replaced due to possibility of debris getting stuck in it and causing an engine fire.

when i replaced part of my injector wiring, the tape around the wires was very brittle and defiantly not in the condition it should have been. the wires inside we not as bad, but once i cut in there I decided i might as well replace it anyways. Was still easier and cheaper than having the dealership replace the entire engine wiring harness for 1600$ which is what they quoted me would fix it.
 
97XJ Jeeper said:
Hey Doc did #3 look like anything hit it to smash it, that don't sound to good. I don't know how close the piston come to plug on 4.0, like GM's old Tech 4s if the timing belt slips the piston would hit a valve.

the 4.0 has a non interference timing chain. if it breaks, the valves dont drop and hit the pistons.
 
97XJ Jeeper said:
Hey Doc did #3 look like anything hit it to smash it, that don't sound to good. I don't know how close the piston come to plug on 4.0, like GM's old Tech 4s if the timing belt slips the piston would hit a valve.
It doesn't run that bad. If the timing had slipped it would be running way worse then it does now. Right now its got a fairly bad miss that goes away when it warms up. Once its warm it just runs kind of rough. In fact it runs smoother then my old 91 did.
 
I had been trained in the MIL diagnosis for a postion at a former job. When the MIL flashed, it meant a code that came and went away. If the MIL came on and stayed on, it meant that the problem didn't resolve itself and that intervention was needed. Never heard the flash and call a Tow Truck, new one for me. Misfires occur more often than you think and I would think that if you checked your computer often(OBDII), you would see this somewhere. I am not saying that it happens to all, but it does happen more often than you think. Misfires are from several factors, like fuel, air, or spark, as all three are needed for the BOOM. Most of the time, I have found bad wiresets to be a likely cause. Injectors are a close second, and I have yet to see the air one, but I am sure it does happen. HTH.
 
Brings back the nitemare that happened to me when my 98 went down in philly. Ran fine all the way down, stopped, shut off, left off for about an hour, came back and started it up, Terrible miss, check engine came on flashing. I drove it 90 miles home, stuck injector washed the cylinder wall down. Fix was a jasper re manufactured motor... and new injectors from 50motorsports.
 
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