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Unread 01-09-2012, 02:00 PM   #61
SDGBASSE
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Makes a lot of sense Que, I still find weird that he doesn't "see" it being rich, a while back when I had a high pressure issue with mine, the thing was smoking black like a diesel, maybe in his case it's just a tad high. Do you know if the O2 sensor on YJs are precise enough to show a difference in voltage from a tad high and way off the charts, or is it only anything above normal gives you over 0.8V?

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Unread 01-17-2012, 10:25 AM   #62
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Well, the verdict is in: It was the O2 sensor!

Yesterday was the first opportunity to do anything with the Jeep that didn't involve freezing temperatures and wind (this past weekend in NY sucked).

I took some advice posted on here earlier about the header, exhaust manifold, unplugging the sensor and running it disconnected... I first checked the header and though I didn't check the bolts, everything looked "okay" and didn't see any sign that the previous mechanic tried to screw with me (it happened to me once before, long time ago). Next, I disconnected the O2 sensor and started it up cold. Hadn't been used in a week and it was 30 degrees outside. Fired up and ran fine. I revved it a few times and it didn't sputter or hesitate, which it would have (since this condition began) when the temps are cold. Ran it for a minute, shut it off. Waited a minute, plugged the O2 sensor in and started it up. After about 5 or so seconds, the first sputter was heard. I revved it a couple of times and it hesitated only once. Good enough for me!

I bought the (bad) O2 sensor for about $40 at my local Napa store. A new Car Quest store opened up a few months ago, about five minutes from my house, and decided to give them a try. The part was about $67. A lot more expensive than Napa, but hey, if it works...

Took the old one out, put the new one in, and voila! She purrs like a kitten. Ran errands yesterday and drove it to work today and drives great and has not thrown any codes.

This experience was frustrating because the voltage that I was getting off the (bad) O2 sensor made sense - it was reading rich which was what the engine was running rich / running rich because the sensor gave a false reading. When I removed it, it was covered in black soot. Is that normal even though it was in use for about one month?

Once again, thank you to everyone who helped me out!
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Unread 01-17-2012, 11:15 AM   #63
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Glad to hear its fixed and thanks for closing the post.
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[QUOTE=ZeroGravity;10681914]I didn't click the link because it says "power probe" in the url.[/QUOTE]
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Unread 01-17-2012, 11:31 AM   #64
Que89YJ
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Laybackman was right!!!!!

I hate these cheap parts!
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Unread 01-17-2012, 02:10 PM   #65
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Quote:
Originally Posted by Bad_Dog View Post
Well, the verdict is in: It was the O2 sensor!

Yesterday was the first opportunity to do anything with the Jeep that didn't involve freezing temperatures and wind (this past weekend in NY sucked).

I took some advice posted on here earlier about the header, exhaust manifold, unplugging the sensor and running it disconnected... I first checked the header and though I didn't check the bolts, everything looked "okay" and didn't see any sign that the previous mechanic tried to screw with me (it happened to me once before, long time ago). Next, I disconnected the O2 sensor and started it up cold. Hadn't been used in a week and it was 30 degrees outside. Fired up and ran fine. I revved it a few times and it didn't sputter or hesitate, which it would have (since this condition began) when the temps are cold. Ran it for a minute, shut it off. Waited a minute, plugged the O2 sensor in and started it up. After about 5 or so seconds, the first sputter was heard. I revved it a couple of times and it hesitated only once. Good enough for me!

I bought the (bad) O2 sensor for about $40 at my local Napa store. A new Car Quest store opened up a few months ago, about five minutes from my house, and decided to give them a try. The part was about $67. A lot more expensive than Napa, but hey, if it works...

Took the old one out, put the new one in, and voila! She purrs like a kitten. Ran errands yesterday and drove it to work today and drives great and has not thrown any codes.

This experience was frustrating because the voltage that I was getting off the (bad) O2 sensor made sense - it was reading rich which was what the engine was running rich / running rich because the sensor gave a false reading. When I removed it, it was covered in black soot. Is that normal even though it was in use for about one month?

Once again, thank you to everyone who helped me out!
Quote:
Originally Posted by Que89YJ View Post
Laybackman was right!!!!!



I hate these cheap parts!
Thank you veddy much! Hey, even a blind squirrel finds an acorn once in a while!

Glad to hear you are running again!

I went through the el cheapo O2 sensor issue some years ago. I assumed the new el cheapo O2 sensor I installed was the fix. But, like you I continued to experience the same issues as before.

I spent a couple of hours of puttering around under the hood doubting that the O2 sensor was the issue. Hey! I figured, I just replaced it. But I did what you did and that proved it was the el cheapo O2 sensor. Bought a Denso O2 sensor and it fixed the problem.

Why does the O2 sensor be the one sensor that seems hard to replicate?
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Unread 01-17-2012, 02:17 PM   #66
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Well, I'm amazed - first time I've heard of a prob with the NAPA parts - I always use their "gold" stuff. Congrats on fixing it! it had me stumped for sure!
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Unread 01-17-2012, 03:23 PM   #67
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Well, I'm amazed - first time I've heard of a prob with the NAPA parts - I always use their "gold" stuff. Congrats on fixing it! it had me stumped for sure!
I agree. I have often used their parts for a long time also, BUT those damn O2 sensors seem too be hard to replicate or they are not compatible with the emissions systems in some cars..I don't know.

I beleive that the last two I used were Denso sensors.

I was often told and I have often read where the answer was; "Go buy an OEM O2 sensor."

Got to do some research on the O2 sensor thing.......
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Unread 01-17-2012, 03:44 PM   #68
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On my old Chevy truck, which my dad now has, I always used Autozone because that was all that was available. Technically there was a Napa store but the manager there was an a-hole and refused to go there. That was when I lived in Florida.

Fast forward many years later, I've used Napa for everything else in the past ten or so years and never had issues. This was the first time I've bought a bad part from them. (shrugs) Guess it happens.

I mainly opted to go to the CarQuest place only because I wasn't in the mood to drive the 20 minutes to Napa and secondly, I wanted to rule-out that the possibility may be the manufacturer of the part.

There is an Autozone near my Napa store, but there's always a line of people at the counter. It's a new store and I don't know if they're just slow or very popular.
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Unread 01-17-2012, 05:57 PM   #69
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ARRRRRRRRRGH!!! Okay, now I'm pissed. (sigh)

Yesterday, I drove around about five times - start, drive, park, shut-off, repeat - and when I got home after all of them, no codes (12 and 55). Drove to work today, no problem (it's about a 20'ish mile drive, mostly highway, and then part city). Still, no problem.

Got in it tonight, cranked it up, immediately noticed it making the same 'hesitation' sound that it makes when starting cold, and running rich. Revved it a couple of times and it sputtered a couple of times. Drove it home and checked the code. 12 - 52 - 55. So once again, it's throwing the code that it's running rich.

Alright, that's two O2 sensors. The first one immediately gave the problem after it was installed. This one survived six trips with no problems.

So now my question is, what would kill an O2 sensor?
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Unread 01-17-2012, 06:05 PM   #70
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An exhaust leak, a bad catalytic converter or a wiring issue (short).
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Unread 01-17-2012, 07:09 PM   #71
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Originally Posted by Bad_Dog View Post
ARRRRRRRRRGH!!! Okay, now I'm pissed. (sigh)

Yesterday, I drove around about five times - start, drive, park, shut-off, repeat - and when I got home after all of them, no codes (12 and 55). Drove to work today, no problem (it's about a 20'ish mile drive, mostly highway, and then part city). Still, no problem.

Got in it tonight, cranked it up, immediately noticed it making the same 'hesitation' sound that it makes when starting cold, and running rich. Revved it a couple of times and it sputtered a couple of times. Drove it home and checked the code. 12 - 52 - 55. So once again, it's throwing the code that it's running rich.

Alright, that's two O2 sensors. The first one immediately gave the problem after it was installed. This one survived six trips with no problems.

So now my question is, what would kill an O2 sensor?
That is crappy! The O2 sensor may be doing its job and is not bad. We shall say that the old one was junk and you won't feel so bad

If you choked off the air to the engine until the air/fuel mix was out of factory presets the code would light up the CEL and set the DTC.

Five start with no issues.......then bad cold starts. Dump the learned memory by pulling the + battery cable and grounding it out for 30 seconds then stick it back on the battery and fire it up and see what happens.

With a cold engine what happens if you unplug the O2 sensor like you did before? Then when you plug it in?

I wonder if your problem is (another) bad MAP sensor vacuum issue or a failing MAP sensor? It can retard timing when it is going bad or has improper vacuum. That would cause the stumble at idle and if it gets bad enough would prevent starting at all. We just discusssed this in another thread.
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Unread 01-18-2012, 07:36 AM   #72
Que89YJ
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Now I am going back to what I said. Check the fuel pressure. Get a guage and run around with it on and see if the pressure is steady.
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Unread 01-20-2012, 09:36 AM   #73
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Dump the learned memory by pulling the + battery cable and grounding it out for 30 seconds then stick it back on the battery and fire it up and see what happens.
I have a fuel pressure tester on the way and should arrive on Saturday.

Out of curiosity, what's the difference between pulling the negative cable for a minute versus pulling the positive cable and holding it to the metal frame? Does one just do a better job of clearing the codes than the other?
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Unread 01-20-2012, 01:23 PM   #74
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In theory, by grounding the positive cable you're trying to fully empty the capacitors in the ECU.
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Unread 01-20-2012, 02:30 PM   #75
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It doesn't matter. We usually disconnect the negative in the lab to avoid shorts.
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