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Discussion Starter · #1 · (Edited)
Can you find the bad spark plug(s)? Explanation at end of pictures......










I bought $34.10 (8.8 Gallons) of premium gas at a Chevron in Cortez Colorado. Just on the outskirts of Gallup New Mexico, I started getting the *DING* and check engine lights. Code was P0301 - Cylinder one misfire. The engine was running really rough and was losing power. I figured, oh great, more bad gas. Stopped at a PEP BOYS and got some dry gas. Dumped it in. I stopped at a Texaco and filled up with another 11.8 gallons of 91 octane premium. Pulled out and hoped that the rough running would go away. No dice. Pulled off at the next exit and traveled down old hwy 66 finally stopping at a Best Western for the night. Saturday night, 5pm, in Gallup New Mexico. Wonderful. Unhooked the trailer and drove back to Wal-Mart. Got some fuel injector cleaner. Dumped that in. Still ran rough after 10 miles of driving.

Sunday pulled the trailer another couple miles down the street to a KOA campground and checked in. Monday at 7am was in front of the local Dodge dealer's service bay (they didn't open until 7:30). An hour later the service writer brings out this long list of possibilities including plugs, wire, coils, and injectors, some of which they'd have to overnight. He also said that there was three codes (the SCANGAUGE only displayed one. Hmmm...) I had a miss on cylinders 1, 4, and 6. Huh, a three cylinder jeep! Had them pull that #1 cylinder plug and that is what we saw. Saved all the plugs for posterity.

So, another 3 hours later and $393 and change, the jeep is running perfect. As a courtesy they washed the jeep. Unfortunately they didn't consider my CB antenna and broke it off. Didn't discover THAT until I got back to camp. Naturally. Sigh.... Well, LOVE'S had a replacement and $26 later I have that repaired.


So, me and VISA.... we're tight.

I hope to get out of here tomorrow morning and back to Dallas by Wednesday night, missing two more days of work with no pay.


I have to look on the bright side. At least I didn't break down miles from civilization requiring a really expensive tow, AND the spark plug element didn't break off and score up the engine cylinder requiring an even more expensive rebuild. Now I can only hope I didn't burn a valve in all that. We'll see.

-Joe

*edit* - Forgot to mention. At the time I pulled into the service department I had 48,101 miles on the odometer. 23 months of JK ownership.
 

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The problem looks like the ground electrode being smashed down against the center electrode. there was no gap for the spark to jump, hence, no ignition in that cylinder. The scary part is, what smashed it against?
 

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Holt crap, what's with the gaps? Not one is the same, two completely closed, one almost, the others, who knows?? Are those the stock plugs? Looks like thet're too long in the cylinder and the piston is hitting on them....I'd take a boroscope and check out the tops of the pistons. Sorry about the bad luck, I hope were're not all in for this nasty surprise...
 

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x10 on that plug gap. were they dropped or was that how they came out if the head, if thats how that came out of the head it has nothing to do with gas, something physically hit the spark plug.
 

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very interesting, I wonder what the "real" problem is.

gaps do not close on their own although a tech could have thrown them into his box...
 

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Two = completely closed/ One of those completely blackened...
Another is almost as closed as the other two...
And if you look closely at the really bad one again, you can tell it wasn't dropped or done by human means. It looks like a continued hit from a piston...almost in a circular pattern.
 

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Now that I think about it, I think there was a tsb out for certain JK's that had the wrong plugs installed in one side of the engine. That would account for your 3 plugs with no gap. and yes, I'm almost positive that Champions are the factory plug. I never had luck with them, even in lawnmowers. I usually stick with autolites.
 

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Discussion Starter · #16 ·
*UPDATE*

Well, I made it back home, not without some further excitement. Hold that thought.

The gaps shown in the photos are as they were when the plugs were pulled... basically all over the place. I *think* (pure, unadulterated speculation) is that the plug electrode overheated and bent to touch the center electrode. Notice that there are two other plugs that are bent "in" and appear to be discolored from excessive heat. I just hope I didn't burn a valve in all that. I think the missing material on the electrode is from excessive heat and spark. The really scary thing is the electrode is cracked at the pit and was really close to breaking off.

Those are the stock plugs that came with the engine. Dead at 48,101 miles.

The first tank of fuel AFTER the plug replacement I got 15.6 mpg. The tank had the remains of one bottle of HEET drygas and one bottle of STP Fuel Injector Cleaner in it. This segment was from Gallup NM to east of Albuquerque NM. Altitudes ranged from 5000 to 7000ft. I was towing in OD with lots of power and little downshifting.

The next tank I bought at a Conoco station. About halfway through that tank, I lost power, the engine stumbled and one time I had to pull completely off the interstate and stop. Ever been to Eastern NM/ West Texas? There ain't nothing for miles and miles. Literally. I did a 2nd and 3rd gear 50-60 mile drive to the next gas station in Texas. Very little power. I lost velocity on every hill, even when it downshifted to 2nd. TOTALLY different from the previous tank of gas.

I filled up at a Texaco station (after adding another bottle of HEET) on I40 in West Texas (13.3 mpg), and continued on. It took another 50 miles of driving before the engine seemed to settle down to 'normal' power. Stopped for the night. Filled up at a Shell (90 octane 'premium') after adding my remaining bottle of STP fuel injector cleaner (10.5 mpg)

Filled up at an Exxon station (93 octane) on the final segment home (10.3) mpg. Power is mostly restored. no longer struggling to get up and down hills, and the cruise control holding the speed.

So, tomorrow I plan on finding some 'surface gap" style plugs and trying those. I have a (non-tow) trip planned to Missouri this weekend (900 miles r/t) so I'll have an immediate comparison. I'll take pictures of the 'new' plugs pulled (I have just over 900 miles on them at the moment) so I'll see how they fared from the tow over the mountains.


And that $450? That is not even a quarter of cost. Repairs, lodging, food, 2 days lost wages, miscellaneous expense.... this was one expensive repair! BTW, if you didn't catch it, the repair bill was $393. $105 for plugs (P*ss poor replacement champions at that! at $17.50 each/dealer price), $226 for labor (4 hours, a bargain), and the rest for taxes and that nebulous "shop supplies".

Any thoughts on those surface gap plugs?
 

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Wouldn't the best idea be to go to the dealership and grab some Mopar plugs. Surely this is an issue that has been addressed if there were other jeeps with this problem. Is the jeep still under any kind of warranty? If so, why should you eat this cost yourself. I feel like going back to TSB site and looking to see what year (build date, before...) has had this (possible) same symtom. I sure don't want this thing sneaking up on me in XXXX amount of miles. And those three plugs on the pass side look like a PITA to access.
 

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I pulled my plugs the other day, and they were the same Champion part #, but they looked fine. Just the usual amount of wear you'd expect after 40k miles.

I've never heard of bad gas bending plug electrodes before, and not sure how it could do it, I personally doubt heat caused it to bend.

There are pretty much only two ways I would expect the electrode to bend, by been impacted by the cylinder, in which case you'd expect to see an impact pattern, or by a large carbon deposit, which could have come lose from all that cleaner you put in there.
 

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One question...why are you using 91 octane gas?
 
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