outofrng623

Thanks for looking. Three mechanics, lots of posts elsewhere, lots of reading and no resolve.
2004 JGC 4.7 non HO
Jeep went from 13mpg around town to 6 during winter blend. Up to 8-10 around town now. I easily get 19 highway. Too drastic a difference. I feel the original problem is not resolved and my mileage has only gotten slightly better due to gas blend and new components.
Symptoms and situations, rough idle like light miss. WOT does not produce code
A few weeks after Cats were done, p0420 came up constantly. Changed o2s, no issue for weeks now it comes back every so often. Cats are new
I have a surging idle, not by much but the purr gets louder then settles when idling. Maybe once a month the truck will stall while just sitting idle. Ive stalled once or twice going into reverse. Once or twice pulling up to a traffic light.
I do have a air rushing sound, believe its just the throttle body.
Slightly hard starting, if it doesn't start within 3-4 seconds, if I key off it will not start easily the next try, third is usually the charm.
Mode 6 fails, TID 11, 31 both o2 half cycle counts and 51 purge monitor IAC shift, sometimes 52 purge monitor adaptive fuel shift, 53 purge monitor rpm shift, 61 & 62 both leak detection pump period. I was told my purge solenoid is overactive, but no one can tell me why.
Downstream o2s look lazy from time to time. I get some clunky transmission action here and there. Like a weird downshift or upshift when around the shift points, around town. Not highway.
Disconnected pcm, checked connectors, no changes.
Map sensor checks as working properly
IAT and coolant sensors check ok




The issue was present prior to anything done below.
I have done.
TPS mopar
IAC Mopar
All 8 coils new
New plugs champion copper
Air filter
Oil changes
Fuel filter/pump Mopar
New exhaust, high flow 3" both cats and back.
New o2s' all 4 mopar
TB cleaning-multiple
New thermostat
New gas cap
Trans filter
Coolant system pressure tested
Vac system smoke tested
No dragging components
New alternator, 160amp instead of the 134 (136?)
Exhaust manifold gasket
Valve cover gasket


That's all I can think of at the moment. Any help is appreciated.

Bustedback

Are Champion coppers the correct plug for this engine?

outofrng623

Yes.

Bustedback

The downstream O2 is not supposed to switch like the upstream O2. If it is switching like the upstream you have a bad catalytic converter. First thing to check is the long term fuel trim. If the numbers are in the plus range you need to figure out why the PCM is requesting more fuel. Looking at the data stream will help determine what's going on if you know what all of the numbers and values mean. The sensors that are key in making fuel strategy decisions are the MAP/MAF, TPS, VSS and the upstream O2 sensors.

sycoglitch

IIrC, in the lAter year 4.0s, both up and down stream deal with the fuel and not just uppers like in the older pre 97 jeeps.

fishbone

Very interesting issue. In my humble opinion, you are wasting your time chasing after this problem by replacing emissions related components and or sensors. I am making an assumption here that you replaced all those components because of the fuel economy issue correct? Were there any other issues, besides the fuel economy that caused the vehicle to throw a code or multiple codes prior? I am at a loss here as to why you changed out the CATS. I may get some backlash for saying this but, CAT's usually don't go bad. Now, realize we are working on a Chrysler built Jeep and I did say usually. LOL. Cat's usually fail due to catalyst damaging events such as misfires where unburned fuel enters them and breaks down their components. My concern here is now that you've replaced them, did you use OEM Cats or did you use cheaper one's? I know you said high flow so I assume they are not OEM. I know guys that changed out the Cats simply because they were putting on duals or cat back systems and wanted all the components replaced, but did not use OEM cats and ended up with this very same issue. Now with that said and because you have done exhaust work, please check for leaks especially at the exhaust manifold gasket on the bank indicated by the code. Because you are experiencing a rough idle or a surge and or stalling, check fuel system. A high pressure fuel condition can cause this issue. Does this model have a pressure regulator and is it vacuum actuated? Check for proper operation of the injectors on that bank. Lastly, I would check compression on the engine. May have a bad cylinder.

outofrng623

Hope I hit everyones questions/comments. First, thanks!
Bustedback. Cats are new. Month or two old now. Didn't throw code until about 3 weeks after I got them. Changed the cats because I was getting the rotten egg smell and the performance issues. I am going to post two videos that show my data, plus three pics. No Maf in my Jeep, MAP tests fine, TPS has been changed, mopar...VSS, never checked or considered until recently. Sycoglitch. up and downs. From everything that I have researched, the ups do rely ever so slightly on the downs, but...No where near enough to be causing my issue.
Fishbone. No codes at all prior or during the issue except for a bad coil, long after the issue started...and I changed all 8. Cats, mine were clogged up. I got an exhaust through Kolak. Many have for years and I haven't seen one issue mentioned anywhere from anyone about it. I did check for an exhaust leak and there was one, exhaust manifold gasket, drivers side. It was repaired. Fuel regulator, done twice, once a wix, second mopar. Pressure was checked and comes up ok. Injectors and compression have not been done yet. Now...Onto todays events.
Ok, so today I threw the p0420 again. 10 minute highway, then about 5 min city (not stop and go, 30mph, light here and there) and the code came up. The o2 pic below was just taken. These are my old o2s. They were in the truck for a year. Densos. I changed them to MOPAR because of the code. Left is 1/1 Right is 2/1. Big difference in how they look. I am guessing something is horribly wrong on the left side of the motor. So what would cause an 02 sensor to fail time to time? Also is a pic of my o2 waves (top is 1/1 red 1/2 green, bottom 2/1 red 2/2 green) and freeze frame data right after the code hit and I am going to post a video of my data when it happened. The videos are long. I think the issue happened around the 4 minute mark and the CEL came on around the 6 min mark.
As always, thank you all.
Videos here
https://www.youtube.com/watch?v=621E6zgO60Q
https://www.youtube.com/watch?v=X3BACqYgkOs

outofrng623

Let me also add something that I didn't put into the original post.
I have a remote starter. Every once in a while, maybe 1 time out of every 50, I hit the button, it starts, it runs for about 10-20 seconds, shuts off and then restarts. From what I understand, the unit uses a sensor to see rpms and/or voltage to confirm, the car has started otherwise it resets and tries again. Maybe related? If so, how?

fishbone

Based on the data I've seen looks to me as though the O2 sensors are doing their job and the LT and ST fuel trims are being adjusted properly. Based on the data I've viewed, I would not guess that your fuel economy is poor. Although the you tube vid showing the live data was blurry on my end but from what I could make out seemed to show normal adjustments, perhaps I did miss something. There could be an event happening from time to time (prob a miss) causing some of the larger adjustments however, LT and ST trims were not going lean or rich again, indicating to me that there is something wrong internally. I would def. do a compression test and I would take another look at doing that pressure test to re-confirm the head gasket. Is your oil good? Any contamination? Fuel or Coolant in the oil? There is something going on causing the Cat to not be able to fully catalyze the mixture going in.

outofrng623

Thanks...This is why it's been such a long ongoing issue lol I have a specific question. I have an air whistle that I hear inside...When I go under the hood I am led to believe its the throttle body or IAC letting air in which would be normal...but, yesterday I started thinking it's not. Reason being, at one point I heard it and slowly hit the gas and I still heard the whistle and it didn't change. Another reason, at one point idle, there was no whistle. Things that make you go hmmmm. I also noticed that possibly...at certain points of pushing down my gas pedal, I have no change in rpm or power. I have to pay more attention to that and do a TPS test. The TPS is new Mopar...new being a year.

outofrng623

Let me add.
Oil appeared good last check.
Something is fouling up my o2 sensor. It appears to me to be a rich condition but I'm not sure what's causing it. It's only an issue on bank one. Old o2 started throwing a code every time would would go through the testing parameters. Changed the o2s, no issues for weeks and then it came back. Based in the o2 pics above I say it's fouling. I have no smoke so I do not believe it's oil blow by. I do have a list of things I'm going to do or have my guy do hopefully soon. If it was coolant getting through the o2 would be whiter.
After all these troubleshooting steps and changes etc I'm down to believing it's related to either the evap purge solenoid or a leaking injector. After I fill up today I'm going to run a tank with the evap solenoid disconnected. I was told it was over active at one point. I also want to see if I have any vap coming though when it's not active. So continues the saga.

outofrng623

Did you see how around the 4 minute mark the o2s went flattish? That to me is odd and the circumstances are long highway drive, then coming off the highway, a stop sign or shortly thereafter the code comes up. Not sure if the o2 fouling is what throws the code or if the PCM makes the o2 go flat for some reason and that triggers it.

outofrng623

Ok. So here's the latest
Checked all plugs. They all look the same, no sign of an issue. Example of one below.
Cleaned iac. It did have buildup but not a lot. Other thing I noticed is the plunger showed wear in one area. It may be getting stuck or slowed. Not sure why that would happen.

When checking the tps I noticed the following. Key off showed .13 volts??? Wt...?
Key on .54 volts. Sweep went smooth from .54- only 3.76 at wot. Not 4.5.

Map sensor. Key off .13 again wt...?
Key on 5v
Running 1.46 down to 1.26 at idle. Scan showed 10.3hg

Pcv functions. But when the pcv is pulled from the hose, smoke comes from the fresh air hose for the crank case coming out of the airbox. More than I would've expected. Possible blowby? I did also note oil in the hose that connects to the plastic hose that connects to the pcv.

Checked purge solenoid. There is no flow unless it's activated. I cannot blow through it.

I was low on oil. That's not to say that it was filled properly at the last oil change or it leaked out. I do still have a leak at the pan.

I have no smoke in my exhaust. I do have a lot of moisture though.

Thoughts? Thanks

Bustedback

Moisture from the exhaust is a good sign the catalytic converter is working properly.

outofrng623

That's a good thing. Whew, finally something good. Lmao. Thanks.
Now. For everything else? Thrown by the voltage showing when the car was off. Although not a high voltage, not sure if it's normal or if there is some short or problem somewhere...that would cause a problem while running. Maybe the PCM is fluked? When the weather cools a bit I'm going to try some other positive points to see if they also hold voltage, if they do I'm going to disconnect the positive and see if those harnesses still show voltage. If they do I can assume there is something in the system that holds voltage for a while. If they don't, I'll have to figure out where that stray voltage is coming from. Then I'll have to look into of the stray voltage items are within the same PCM harness or not...ugh