I hope this becomes a tech post, but as of now it's just me troubleshooting. I've researched a lot online this week, and found some similar issues, but nothing that has fixed my jeep.

My daily driver is a 2001 WJ 4x4 with the 4.7L (my kids call it the shiny jeep). Tues evening just after the storm I stopped on my way home from the gym to run along the canal in the desert. When I started the jeep to leave it ran like crap, idled real rough and felt like a cylinder was not firing. When the check engine light came on I checked the code by cycling the key 3 times and got P0202; nothing else. That code indicates a problem with the injector control circuit for cylinder 2. "An open or shorted condition detected in control circuit for Injector # 2 or the INJ 2 injector bank." I figured it was a bad injector and pulled into the garage to work on it.

While researching the code, I found a lot of people get random P020x codes that are caused by a TPS sensor malfunction. I figured that would be a quick fix so I started there. One trip to O'Reilly and 2 torx screws and the new TPS was in. Unhooked the battery to reset the codes, fired up the jeep and it ran like crap. Code light came back on and gave the same P0202.

No problem, next thing to check was the injector and coil on cylinder 2. Swapped both with the cylinder next to it, breaking almost every old and dried out electrical connector clip, and put everything back together. Unhooked the battery to reset the codes, fired up the jeep and it ran like crap. I expected this and hoped the code would move to indicate the other cylinder. Code light came back on and gave the same P0202. not what I had wanted to see.

At this point I'm figuring there is a short in a wire or a problem with the PCM. I checked the wires visually and found no obvious breaks. I called a shop I trust and the guy told me he's seen this a lot with Chrysler, the PCM has a driver for each injector and they go bad and throw the P020x code. He tells me to take it to the dealer to get a new PCM. I know better than to let the dealer charge me a gazillion dollars for them to guess through all the same stuff I already did, so I call around and find a PCM at ACM Salvage. Not cheap but 1/4 the price of a dealer one and ready for me to pick-up. I figure I will still need to get the PCM flashed, but that's not too big a deal. Skip to an hour and half later and the new PCM is in, codes are reset. Fired up the jeep and it ran like crap. At least it fired I guess. The PCM is synced to the Sentry key, so I was happy I could keep it running, but not happy that I have made no progress in 3 days.

So I'm lost. I can't see any reason for the injector code. I figured it is better to have a shop or dealer diagnoise it for me at this point so I can just skip to fixing it. I hate doing this, but it's not worth the time I'd need to trace the wires and ohm out the PCM.

Good news is I've got to spend a few days this week driving the dirty jeep. :))

wow, I don't blame anyone if the first reply is tl;dr. LOL

Well, that sucks. Wish I could help. I figured someone on here might have an idea if you posted it here.

I had similar issue on the TJ. I replaced the CAM, Crank, Throttle sensors before taking it in to have the PCM swapped. The swap didnt exactly fix it but it did throw a diff code after the swap. I forget which one exactly but it pointed towards the crankshaft sensor on top of the transmissions. Previously I had used a generic autozone part but thought id try OEM stuff from the dealer this time. That turned out to be the problem. The cheap electronic stuff from autozone wasn't working correctly. Lesson learned, buy OEM for electronics

It could be anything, but i think i would pull all of the tape and plastic covering off of the harness and check for breaks in the wires to that injector. How does the connector itself look? Is it really corroded? I honestly would start at looking at wiring before I would go to the severity of taking it to a shop. How does the spark plug look (didnt see that mentioned)?

No word from the shop yet.

Bill, I figure it's something in the wiring too. Connector is good and so is the spark plug. I was out of town this weekend and am busy with work all this week. Unfortunately best option was to let the shop diagnose it and then I can decide if I have time to fix it.

Oh, that makes sense. Well if you need any help let me know!

thanks Bill! I'll post up here when I find out what's wrong.

Anytime Matt!

shop called and said I have no compression in Cylinder 2. I guess I should have checked that a home, but didn't really think it was something that serious. They said it needs a new cylinder head.

I'm thinking I'll tear it apart and send the head in. Anybody think a new/used head would be a better idea?

as long as you have a good machine shop then a rebuild is the way to go.

So to make my decision harder, Greg from Gregs Auto quoted me $350 for labor. I already have the machine shop that did my XJ motor work ready to do the rebuild. So it's just a question of do I pull it myself or do i let Greg do it? I'm thinking he can do it faster than I can. I'm not in a huge hurry, I'm almost used to not having ac. Haven't taken a 4.7 top end apart before, so I'm sure there will be some snag I'm not expecting.

Do I do the work myself bcz I can even if it takes my a week of evenings, or do I just take the great deal and have Greg do it?

It is nice to have it done and just to go pick it up...

If you can afford to have someone do it let them, because then it is under warranty and you have a piece of mind! If not, then you know the answer. I do all things myself because i actually like to build stuff, but then again I dont always have the time to do it!

Good news: I found the problem.

Bad news: it took me over 3 hours to take off the valve cover. Well most of the way off, didn't drain the coolant and remove heater hoses so I could pull it all the way out. Soo much crap in the way.

Something is missing here...


Pretty sure this should not be laying next to the cam...


Didn't expect it to take me so long, so I'm gonna call Greg and see when I can drop it off.

ouch!

That stinks man...

wow.. that sucks.

The problem ended up being a broken valve seat that dropped into the cylinder and managed to bend the valve. This didn't allow the valve to close and then the rocker worked its way out.

I had planned to pull the head and rebuild it, but I would have pulled both sides and with the 4.7 the cost to do that was getting close to rebuilding/replacing the entire engine. Since the motor had 171k, I opted to spend the extra and replace the whole thing. I found a place that sells rebuilt motors out of Michigan called Accurate Engine. They had good reviews on the motor builds and are supposedly the #1 4.7 builder in the US. After going through all my questions with Alan (not our Alan), I put in my order. Something happened along the way that delayed my order by a week, but no biggie. In the mean time, I decided to have a local shop do the install. I'm becoming less adventureous when working on my daily driver vehicles. I don't mind doing the work and enjoy it when it's an extra vehicle, but I want my nice one back up and running quickly. So Paul the owner of Brakes Plus on 83rd and Deer Valley got me set up with Barrett to do the work. They did an awesome job. They let me choose what things to do later (need to replace an AC line and a radiator hose), and took care of the things that were best to do with the motor out (motor mounts and replace cracked and warped exhaust manifolds). I've got about 1000 miles on it now. Have done the 500 mile oil change and had an exhaust leak fixed since the install and everything seems great!

Can't wait till the motor is fully broken in so I can test the claim of an 8% increase in horsepower. :))