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Discussion Starter #1
Hey Guys

I have a 2001B5 1.8T (AUG) that has started to misfire pretty good all of the sudden. Had the car for like 7000 miles and it's ran amazing. Happened on my way home from work monday, off and on but I got it home (20+ miles). Did some research and decided to start with changing the spark plugs. Car has 272k on it so I figured its time for some fresh plugs. Went to the store and got some BKR6E's and started putting them in. Cyl's 1,2,3 went as they should (I was shocked), then I came to #4. That guy's in there pretty good. I'd say I have about 90deg of rotation from tight to the point where I don't want to turn much harder. I've tried a bunch of stuff: lots of PB, Carb cleaner, hot, cold, overnight w/PB. Doesn't seem to help any. I think I can get it to loosen farther with a cheater bar on my ratchet but I don't want to break the plug off at the head and deal with that crap. Normally I'd just leave this one in but the other three old ones were REALLY bad autolites and the gap was huge. What would you guys do? Any help would be appreciated!

-Jarred
 

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hate to say it ....but I believe the plug threads have bonded with aluminum head and you are fundementally twisting the threads out as you back plug out....you could try a little kerosene (if readily available) or WD 40 as either one of those are used when machining or tapping aluminum, b'laster penetrates super, but does want to"bind" when tapping......you got to get galled aluminum "welded" to plug threads to separate.......ugh!
 

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Hmmm never thought that would be possible but it defiantly makes sense. Crap. Guess I'll just have to use some force to take it out/snap it and deal with it. Time to get familiar with a helicoil.
 

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If you haven't removed the plug yet, try some more PB, but only move the plug within that ~75-90 degrees of rotation until it turns a little (subjective, I know) easier.

Got lucky doing a plug change once with a B4 Passat (VR6) that had plugs left in for ~75-80K miles. No visible center electrode on two plugs, yet it still ran, somehow. :crazy:

Good news is your engine will be "smooth as butta" with a new set of plugs due to the random misfire with old plugs.
 

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It would pain me to do this for a "simple" spark plug change, but if it were my car, I'd take it to a shop and have them deal with it. Of course, don't be sneaky... warn them of the situation, and verify they have the tools and expertise necessary to deal with it if the plug does snap and/or the head strips.

If you've never used a helicoil before, I'd say that an application where doing it wrong is going to shred your engine is probably not the best time to learn.
 

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would using the spark plug extractor tool that is commonly used on Triton motors work in this situation?
 

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Discussion Starter #7
I'm starting to think I should hold off on this one plug and continue figuring out what's causing my misfire. I have two coil packs coming today (one original was kinda bent - could be screwed up) and I'll try the vag com to try to figure out which cyl is misfiring. It could also be the MAF, I've had a code for it for a long time but it's never been an issue. I'll try unplugging it to see what happens. I don't want to put a ton of time+money in this car since it's just a commuter/beater but I'd like it to run without shaking lol
 

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Sounds like you've tried most of the common approaches. I'd run the engine until just warm, not hot, which will expand the aluminum slightly. With plenty of penetrating oil at the base of the threads, work that plug back and forth, and perhaps gradually the range of rotation will increase. Take your time and don't force it, otherwise the Heli-Coil will for sure be the next step.
 

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I'm getting the impression that the threads have already broken off, and the reason you can't get it out any more is that that section is simply getting stuck in the part of your head with working threads.

Certainly you might have coil or other problems also, but it would not surprise me if it was those plugs. The 1.8T is really picky on plugs to begin with, and it isn't going to be happy with a worn-out Autolite in there.
 

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If the plug is not destroyed yet, it might be easier to run the car until it gets hot, the plug may come out with less force.
 
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No matter what, this is a risky deal and it may have a bad outcome even with the best method.

Lots of good advice here but...some say the best you can get is acetone + automatic transmission fluid (50/50 mix) for freeing seized threads, and this may be the time for that.
Just ask ChrisFix

The method I would use is to put a small amount of the ATF & acetone mix in the spark plug hole.
Let sit overnight.
See if it comes out then, but don't force anything.
Take the car out and let it heat up.
See if it comes out then, but don't force it more than a fraction of a turn (let's say an eight of a turn).
Put more of the ATF & acetone mix and hope that the mix can now seep in since you loosened it up to some degree.
Then move it back and and forth in both directions (definitely don't tighten more than it was originally).

I always assumed that the back and forth motion sort of grinded the rust particles into finer dust, which is better than continuously forcing it in one direction.

For something this important, I would make sure I didn't skip a step and not get impatient...it make take time and the right kind of coaxing. :)

I hope I don't have to tell you that any solvent sprayed on a hot car can ignite.
 

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Discussion Starter #13
Well guys I got the spark plug out. Unfortunatly it took some of the threads with it... For future reference, here's what I did:
1. Bought Kroil penetrating oil (heard online it's better than PB blaster - I believe it)
2. Sprayed a bunch down in the hole and let it sit for like 4 days
3. Took a weak impact to the plug for a few minutes in both directions to (hopefully) jar some crap loose
4. Used a big ass 1/2" ratchet and my (small) muscles to back out the plug, work it both directions

I can't believe the plug didn't snap off down there. But I do think this has a lot to do with my misfire problem though since this plug was f*****, the gap is like .060" (twice spec). I thought it was funny how the 4th plug was different than the other 3, I bet someone was changing the plugs at some point and decided the 4th wasn't worth it.

Now it's time to put in a heli-coil and be done with it (hopefully). I'm pretty good with working on stuff and machining so I'm not too concerned.

Take a look at the old vs a new plug!

file-1.jpg
file1.jpg
 

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Discussion Starter #16
Well, there's good news and bad news.

Good News: thread repair went pretty well and I was able to install a new spark plug. Was able to drive it around home last night and all seemed well.

Bad News: The misfire is back. Got in the passat to drive to work today and as soon as I let the clutch out to get rolling it started jerking again... Last night I replaced the one coil pack that looked physically damaged but the problem seems to persist. Any ideas on where I should go from here?

Like 100 miles I attempted to clean my MAF sensor, the light has been on since I bought the car so I tried to clean it with MAF cleaner. The light is still on and throws the code. Could cleaning it like this cause a problem? I've read that a MAF can cause a misfire.
 

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don' t know how exactly you did thread repair,but is "misfire" at same cylinder? Have done work without removing head in past and had a piece of "flotsam/jetsam" find its way to electrode......also can interchange coil packs and see if code follows.... thanks for updating,interesting to find solution
 

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Get it scanned for codes. Multi-cylinder misfire is probably a vacuum leak. If single cylinder misfire, you can swap coils to see if the misfire follows the coil. Single cylinder misfire could also be bad injector. You really can't go further without knowing the type of misfire except to just start replacing everything.
 

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As mentioned above, check the fault codes. A single cylinder fault will be due to spark, fuel, or compression problems. A MAF fault can be narrowed down by disconnecting the sensor, which will cause the ECU to calculate fuel injection from the remaining signals, so if the running improves, perhaps the MAF or it's electrical connections are defective.
 
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