Random multiple error codes and noise after engine replacement.

Hi all,

Wasn’t sure if anyone is still working on these 1st gens and just saw that some are! So I posted a thread several months ago about swapping engines from an 04 sport into an 02 limited, took forever as I only get a couple hours a week for this project and everything that could go wrong basically did but none the less the engine is in and running however, I have some serious gremlins I can’t seem to evict.

So after splitting both engines and swapping the crankshaft reluctors, and cams shaft sprockets along with all the 2002 model sensors, I’m getting random 02 sensor heater circuit errors and some times random misfire codes but not as frequent as the 02 sensor issue. It acts like a bad ground right? I found 4 grounding points two on the block for the battery and main wiring harness and the heads are grounded to the firewall. Well I’ve since removed all ground studs and wire wheeled them and sanded down locations and connectors, coated in dialectic grease and re tightened them all with no relief? Sometimes it will give one or two O2 heater circuit faults or somethings all 6. I’ve also seen random miss fire codes in #6 as well as #2 however those clear and didn’t come back? Any help or thoughts would be greatly appreciated.

The other issue I’m having with this transplant is as soon as I fired it up, it was knocking, sounded like it was from dead center of motor or coming from the timing chain cover. Sounds too aggressive to be valve train but too high pitched and intermittent to be a rod bearing, but I pulled the valve covers and inspected, not finding anything wrong, no loose rockers or failed lifters? I then replaced the timing chains, sprockets and tensioners. And it still knocked, I pulled off the torque converter acces cover and inspected the bolts there and was all good. Finally I put in some fresh oil (the stuff in it had been contaminated with coolant several times pulling off the front engine cover) well after the oil change it stopped knocking Awseome! But… after a 20 mile road test the knock comes and goes randomly sometimes faint sometimes just as loud as day 1, but will go away if I keep the rpm’s up under load for a bit? I have to mention I test drove the 04 donor and scanned it before pulling it and it ran and sounded fine with no error codes.

Once it’s all done and right, I plan on doing a full write up in here. I know others have which was super helpful in this project however it seems everyone leaves out one or two things over looked which is understandable giving all the details to this swap. Thanks for any suggestions!

(Tried to attach video of knock but apparently we can only attach photos)

You can link to a YouTube video if you upload them there. Very annoying faults, the intermittent electrical issues sound like a broken wire or loose contact somewhere. The mechanical rattle is odd, I'm not familiar with the v6 but it sounds like it may be a chain tensioner/guide fault, did you replace them?
And I wouldn't ever run an engine with water or antifreeze in the oil it does nasty things to the bearings.

x2 what KJ said - when you first started it up the engine would have been pumping coolant through it first as the oil sits on top of the coolant in the pan which in turn probably caused some bearing damage. How long did you run it with the bad oil in it?

ok, so I did replace the timing chains, guides and tensioners, all torqued down to factory spec. I ran the motor 3 seperate times not more than a minute a piece with the contaminated oil, however 1. The noise did persist before I contaminated it and 2. If it were infact bearing damage you would think it would be constant, not coming and going randomly?

Since my last post I unplugged b1 senor 1 blew out the pin and reconnected, I also did the same with the PCM connections, I’ve since put about another 10 miles on it with no CEL or codes however watching the live data as it runs on my scanner the o2 values along with the MAP value is just bouncing all over the place, Which leads me to believe a possible failing PCM? Could this knock be a pre detonation or secondary det knock? I do have an after market crankshaft position sensor in it which is the second one since I started, after reading many comments, I continually hear this car will not work with an after market cps has to be mopar however, I simply cannot find one as it is discontinued. Dealer can’t get it and I’ve searched to the end of the internet with no results?

It might be a PCM fault but as it ran fine before I'd suspect the sensors, connectors and wiring that have been touched, if the MAP sensor is the same as the other engine try swapping it over.
The odd Lambda and MAP could also be an inlet air leak.

When you say your O2 values are bouncing all over which data pids are you monitoring? can you take a picture of the data on the scan tool and post it? A video of the noise would help - does it seem like the noise is timed with crank speed or cam speed?

derekj said:

Update:

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I do apologize for the long response times, I really don’t get alot of time for this project. Ok, so last action I simply replaced all the O2’s and the MAP and yet another aftermarket CPS that came highly recommended from this site (crown). After another 130 miles still no O2 sensor errors so thats great and all however, the intermittent knock I would hear in the beginning came back and I got a pending error misfire code for hole #2. so I pulled it off th road again and parked it. I found the Number #2 spark plug electrode had been closed and the ceramic around it broken off. (I might add that the whole reason I swapped the engine to begin with, was the original had melted piston #2). Anyway, I changed the plug and let it idle,had no knock sounds. Drove it around the block (2 miles) still good, pulled #2 plug and it’s not smashed like the others. So with these new findings I’m thinking I have some serious intermittent detonation knock? After hours of research in this condition I’m thinking it can only be caused by one of three things right, fuel air mixture, poor coolant circulation, or ignition timing? I disconnected #2 coil and fuel injector and let it run on 5 cylinders for about 30 mins at full temp there was no knock so I then plugged everything back up and did the same again no knock. However I’m not convinced it’s not gonna happen again after I put it back on the road. Next step will be to check for proper coolant flow, check the fuel injector. I guess a lingering quesion or thought would be; if it’s gonna melt piston #2 again on a different motor now, what didn’t I swap that could be causing this? Litterly the only thing original to the 2002 at this point is the PCM/ECM and radiator. Could a failing PCM really cause this? perhaps sending the wrong commands to just cylinder #2? Well at this point and seeing how I swapped in a completey unknown high mileage used engine I’m just going to drive it whilst I’m rebuilding the original 02 block. Most people would have canned this long ago however, I’m holding onto hope as I live in the farthest depths of the rust belt and there aren’t many of these left they haven’t been completely rusted out, this one however came up from the south and is still really solid and even after all this I’m still all in around 2k, where I live you can’t find a reliable 4x4 for that kind of moeny. That and after putting roughly 150 miles of test drives on it, it really is quite a pleasure to drive and seems as it will be white capable off road as well deep snow as it is midley lifted with after market wheels and such.

The PCM is a "living" machine. It is constantly receiving and interpreting feedback information from all of your sensors... plus the TCM (trans control module)... and constantly adjusting engine behavior. If you do a swap, you need to go over the complete checklist I posted regarding sensors/coils/plugs/injectors/etc. All of these things are so densely interdependent that its almost impossible to avoid a game of trial an error replacement until you have eventually replaced everything.

All of the parts on that list have a finite lifespan. Plugs have a life of about 30K, PCV and cats about 50K, oil/CPS/CKS sensors and coils/injectors/TPS/MAP/IAT >100K... so consider the age of the parts you haven't replaced yet. I went 305K before my engine blew a ring... and I ended up replacing everything found on that checklist. The only thing I have not replaced yet is the TCM... and I am doing that in the near future because WTF everything else is new.

If you get a misfire on a cylinder, its the same thing as pulling a plug connection. The misfire code (P030x) is a notice from the PCM that you have a "bad cylinder", and the PCM will stop sending an ignition pulse to that cylinder in a naive attempt to prevent continued detonation on that cyl, which could destroy the engine. The intent being that you are explicitly warned to get the KJ to a garage asap and get the problem fixed.

To my knowledge, as educated by multiple practicing Jeep mechanics who supposedly worked on KJs ever since they 1st appeared on the market, once a cylinder stops receiving a pulse from the PCM it does not automagically start again until the PCM has a hard reset (disconnect neg battery term, then positive, cross the cables for about 10 mins to deplete the PCM static memory, which wipes all codes and resets the pcm and TCM to factory new).

Every time I replaced anything, I did a hard reset and set my trip-odo to zero to monitor how far I got before another misfire happened. I am currently at 1100 miles since the last hard reset after a misfire P0304. It took me a year of trial and error (with a lot of guidance from this site, Chrysler-Jeep mechanics, and Customer Service folks at Crown Automotive, Quadratec and Summit Racing.... before I got everything stabilized and performing properly.

the PCM will stop sending an ignition pulse to that cylinder in a naive attempt to prevent continued detonation on

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At least on my '06, the PCM cuts injector control on a misfiring cylinder, not ignition control. The is an to prevent catalyst damage. A plug that fires in absence of fuel isn't going to cause detonation or any other problems.