wolfman96771

I am at my wits end here, so hope someone can help. I have a 2002 Grand Cherokee Overland I picked up at auction. 4.7 automatic. Insurance claim was for "engine fire", but I found nothing to substantiate that claim. No sign of fire any where, no burnt wires, NOTHING. Got it home and charged the new battery that was in it. Everything came on line, except the starter spun and wouldn't engage. Cool man, or so I thought. Put the new starter in and it started, but was running on maybe three cylinders. Strong odor of raw fuel out of the pipe. NO CODES! Changed all 8 coil packs and plugs, runs much better but still rough. At this point I am at least getting codes. Defective airbag clockspring. When I open it up I found the column had been hammer by some half wit, so I installed a used column and new clockspring. I reinstalled the original skim and key cylinder as well. Now I am running on 7 cylinders! Whoo Hoo! Now we are seeing codes, The main code being PO204 ~ECM loose, broken or burnt wire/ Injector 4 circuit open. Changed # 4 injector, I removed the ECM and found frayed wire under ECM Bracket. Taped them up and stuffed a rag between harness and bracket and clean and inspected all connections. Reassembled and started it. Runs better but after three or four cycles it throws codes PO141, and PO161~ O2 censors down stream. Changed both downstream sensors with new ones. Restart vehicle and for the first time drive it! Stupid man... It runs fine under power but stalls as soon as you slow rpm below 1500 or so. Get back home and scan codes again. Throws codes PO442, 445, and 161 AGAIN! I found the evap vacuum problem was a hose off, fixed that as well as checked and confirmed gas cap seal is good. Cleared the codes and restarted. After three start and run cycles code PO204 is back and for the first time I now have PO500 ~ Vehicle speed sensor! I stopped wrenching 20 years ago, so I am having to learn all this new stuff. What am I missing here? I have so far resisted changing the ECM, but I am at the point of surrender. The wires to the number 4 injector appear to be ok, when I unplug them it makes no difference the engine has the same miss, so I believe the code PO204 is correct. Any thoughts or suggestions would be greatly appreciated!

Bustedback

Trace the wires from the sensor/actuator all the way to the ECM. For ***** and giggles pull up some of the carpet and see if there is any evidence of this being a flood car.

CPLSeraphim

I am dealing with similar type issues, and similar codes. Mine is a flood vehicle, replaced a bunch of crap, and waiting on a computer right now. I hope you find out whats up.


Mine is dying and idling like crap, but 3000 RPMs runs fine, when I get her there. I'll let you know what I turn up, and I'll be folling this thread. Best of luck.