Engine Running Rich
- Thread starter Kwanderson2004
- Start date
swampy@06LJ
New Member
I installed new pre cats and converter last night, was optimistic when I saw the ones that came out and when I fired it up at 2:30 am. Both banks had the internals of the pre cats let loose. Also cleaned up the downstream O2 sensors with a little gas soak and carefully blew them out. Took a ~20 mile test drive this morning, it definitely ran better. Still had some mid throttle flutters, visible on the tach. Went home and parked it for about 90 minutes. Jumped back in and the light was back on. Both P0172 and P0175 codes. The Jeep ran the best it has since I bought it but still not 100% right. I think it’s time to get it hooked up to a DRB.
Hey Swampy, you ever figure out you issue. Just had mine pop a p0172 AGAIN yesterday afternoon. If its the pre-cats again that'll make this the 4th set if Cats this Jeep has seen in 30k miles. Last set probably lasted the longest.
swampy@06LJ
New Member
Hey JeepZilla380, I ultimately got things corrected but it was a chain of repairs. After I swapped all 4 O2 sensors and the pre cats, the code reappeared although my Jeep seemed to be running much better. I replaced the cam sensor that’s on the oil pump drive assembly. The test drive went great until I hit 3,500+ rpm going up a hill. Then I got a cam/crank alignment code and could not get over ~3,200 rpm. I pulled the oil pump drive assembly and noticed heavy wear on the gear. Had a friend bore scope and look at the cam lobes/gear. I ended up replacing the cam shaft and OPDA, and putting the stock injectors back in it. I’ve got around 1,500 miles on it now with no reappearing issues.
I just had a new engine put in mine and the old MAP, IAC and throttle position along with the MAF we’re reused and the same issues you describe have been haunting me along with a host of other things I’ve been picking off one at a time. In talking with Chad Golen he warned me “the number one killer of new engines is fuel washing” this was in response to the stuff He has been guiding me through. Interestingly my fuel Economy was terrible in the old engine as well as being sluggish, the new engine was getting around 8/9 mpg and running really inconsistent, anyway with his warning I checked the oil and in just a couple hundred miles it was very discolored and had an odor to it, draining it the color was dark, lucky for me all the other list of issues has kept it parked in the garage Most of the time otherwise I’d probably have toasted the engine it can happen pretty quick. Took a few days to get the sensors, I’m still waiting on the MAP but I’m pretty sure at this point this is it.
Thanks. I’ve been down this path a few times with this particular TJ. It’s been CEL free for a few years now. Over the past 30k miles I’ve replaced all the o2s with NGKs, 3 sets of cats (counting the ones on her when I bought it), sensors, OPDAs, etc. probably my favorite Jeep if all I’ve owned but she’s fought me ever step of the way!
Another thing too about the MAP it can be out of spec enough to cause issues but not so far off the other sensor adjustments in the PCM that it can’t still be compensated for so it won’t throw a check engine light or any dtc’s specific to the MAP even though it causing other issues. I began looking at mine only after seeing the live data looking odd on my OBD2 reader.
Yea, I'm hoping to get it on a live reader this weekend to see what I see. My current code reader just does the freeze codes.
That would be fun, just had to replace the exhaust manifold on my son's XJ. Maybe the two are colluding with each other?