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-   -   Another issue with '04 WK 4.0 (http://www.jeepgarage.org/f203/another-issue-with-04-wk-4-0-a-65908.html)

verboden1 09-25-2013 09:27 AM

Another issue with '04 WK 4.0
 
I have noticed over the past few weeks that when driving at about 1500 RPM, the engine stutters a bit until I accelerate...here are the problems that I have diagnosed.

OBD codes - 0505, which I know is the IAC. I removed it and cleaned it, but the code just popped again last night.

O2 sensor codes had shown before, so I replaced both upstream O2 sensors last weekend. I used Denso O2 sensors

The exhaust blows heavy black smoke under acceleration, and STINKS. Like a cat converter issue (I've posted before about this)

Just got a 1195 code -1/1 O2 Sensor Slow During Catalyst Monitor. This sensor was just replaced last saturday.

I suspect, based on tapping on the muffler that it has a fair share of carbon build up in the muffler, so I will be replacing it this weekend.

My average MPG, based on the overhead computer is.....wait for it.....9.8mpg.

Question....if the muffler is clogger, or if the cat is bad...would the extra backpressure cause the pitiful MPG?

I am a loyal jeep fan, but a crappy mechanic, so at least it's small issues for now.

Any ideas? Will be ordering the bluetooth Dongle and torque app as Frango suggested.

2004 grand Cherokee 4.0 I6

Frango100 09-25-2013 10:29 AM

Re: Another issue with '04 WK 4.0
 
Just for the records, your jeep is a WJ:D.
The P0505 could be the iac stepper motor, wiring or PCM. Was it not you who had the iac wiring damaged? A split second an open or shorted wire could already give this code, while it otherwise could idle normally.
Strange that the 1-1 sensor is showing as slow for cat performance monitoring, but doesn't have a fault for normal fuel trim operation. The torque app would be handy now, for monitoring the O2 sensor output.
I wonder if a clogged or restricted bank 1 precat could be the problem here. Did you check for any exhaust leak from the headers?

verboden1 09-25-2013 11:26 AM

Re: Another issue with '04 WK 4.0
 
Ehhh, I'm an idiot.....Yes...a 2004 WJ. Thanks Frango. your Jeep knowledge makes me jealous sometimes! :)

I am suspecting that there is an exhaust leak, just not sure where yet....I'll be under this weekend and check while replacing the muffler. I'm tempted to remove the rear cat (I know, it's illegal) temporarily until I can shell out the 200+ dollars to replace it. I'm sure that it must be restricted based on the amount of carbon emissions and the fact that my muffler sounds like its filled with sand.

yes, I did find a two wires with bad insulation, and taped them. I'd like to repair the wires with new wire, but there isn't much to work with. Can one buy a new wiring harness for the IAC motor??? It's hard to buy all these parts when I'm filling up every other day.:mad:

Frango100 09-25-2013 01:16 PM

Re: Another issue with '04 WK 4.0
 
Rockauto.com does has a new connector with a part of the wiring for the IAC.
I would check the gasket from the exhaust headers, which seems to be a common point for leaks.
If the main cat and muffler are partly cloged, what about the pre-cats?
And if the muffler and/or main cat are clogged, why then only bank 1 would have the carbon buildup on the plugs?

verboden1 09-25-2013 02:33 PM

Re: Another issue with '04 WK 4.0
 
Ughhh, I guess the pre-cats would probably clogged too then, huh?? I'll start with the muffler and look for leaks in the exhaust system this weekend. Any way to tell if the pre cats are clogged? all in all, I can't be mad at the jeep. The previous owner obviously didn't take care of it, the 1/1 O2 sensor looked like a charcoal briquette.....
I'll keep you updated.

verboden1 09-25-2013 05:46 PM

Re: Another issue with '04 WK 4.0
 
Hey Frango.....any particular dongle that seems to work well with the Torque app?? There are a few on eBay that are cheap, but you get what you pay for. Any suggestions before I order one?

Frango100 09-25-2013 06:26 PM

Re: Another issue with '04 WK 4.0
 
I bought one from China, but i don't know if one is better then an other.
I think i spend USD 15 or so on it. On mine is written ELM OBDII (when i remember well).
What i understood regarding clogged muffler or cat is that it would create acceleration problems due to the increased back pressure.

verboden1 09-26-2013 02:51 PM

Re: Another issue with '04 WK 4.0
 
You are the MAN, Frango.......I'll screw around with it. Changing the muffler tomorrow and I'll tap the cats. Then I'll go from there. Gonna order a dongle from ebay tonight. Even if I don't understand what the app is telling me, it will be pretty cool.
What am I saying???? All I have to do is ask you!!

thanks for all your help!! Won't let me add to your rep again just yet, but you definitely are a Jeep Guru! :thumbsup:

Frango100 09-26-2013 04:27 PM

Re: Another issue with '04 WK 4.0
 
The P1195 code you have now is normally caused by an inlet vacuum leak, MAP sensor failure or fuel injector leaking.
Because the problem is for cylinder 1-2 and 3, there should be something common, but not affecting all 6 cylinders.
The strange thing is that if there was a vacuum leak, that the expected mixture should be lean, while the carbon buildup on the plugs showed a too rich mixture:confused:
Would not expect the MAP sensor or leaking fuel injector yet, because the MAP would influence all 6 cylinders and a leaking fuel injector only the respective cylinder.
Would be interresting to see the O2 sensor voltage and the fuel trim figures, but they probably will show a very positive long term fuel trim (LTFT) and short term fuel trim (STFT) for bank 1 and a high voltage from the O2 sensor 1-1 (around 0.9 V)
An exhaust restriction (for the common exhaust pipe/muffler) would decrease the entire respiration of the engine and would cause power loss, but the O2 sensors together with the PCM should be able to control the mixture.
And you only see black smoke when accelerating, at which point the O2 sensors are not used, since it will run in open loop mode.
We maybe have to wait for the dongle to arrive, to have a look what is happening with the fuel trimming and maybe other inputs.

verboden1 09-26-2013 06:11 PM

Re: Another issue with '04 WK 4.0
 
Regardless of all of this driving me crazy, I do have one thing going for me........I own a Jeep!! I will let you know when the dongle comes in11

Peace

Frango100 09-26-2013 10:02 PM

Re: Another issue with '04 WK 4.0
 
Quote:

Originally Posted by verboden1 (Post 899974)
Regardless of all of this driving me crazy, I do have one thing going for me........I own a Jeep!! I will let you know when the dongle comes in11

Peace

Maybe one is a concequence of the other?:lol:
I hope you know what JEEP is standing for:
J(ust) E(mpty) E(ach) P(ocket)
:thatfunny:


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