Well, after getting a code (along with some knocking) 0606: Cylinder 3 Misfire, I decided to see what I could see by taking the good old NGK Iridium Spark Plug out from cylinder 3. Plugs that costs around $9 a piece 5 years ago. ANYWAY, this is what I found...





Gee, that sucks completely.

 

How old is that plug? That's extremely odd to see.

 

It's about 5 years old.

 

Damn that's pretty old but a plug shouldn't fail like that, at least I don't think so lol.

 

thats still extremely odd...

Im about to do plugs soon... First change in; you guessed it, 5 years.

 

Cant see the pic here at work...

But Iridium should have lasted for a while. Im pretty sure when i replaced my plugs last year the old ones were still OEM original. They didnt look bad at all, jus needed to be re-gapped to spec.

OP, at least u found the culprit. Now replace that bish and get the whip back on the road!

 

cash since u cant see the whole top of the plug where u gap it and the electrode is missing my guess is it in the cylinder some where

op if ur lucky you could prolly get a telescoping magnet and try and fish the pieces out if they havent been lost good luck that reall sucks

 

WHAT!!!!

Are u saying the head/electrode of the plug came off???????

Thats crazy and i aint never hrd of no shyt like that. OP man, that sucks.

O wait a min. Again, i cant see the pic so I DONT know. Now that i think about it, is the threaded portion still on the plug and ONLY the the electrode burned off?

Either way that sucks ***. Does it look like that maybe the electrode completely melted away or does it look like it broken. I find it hard to believe that iriduim would fail like that, but since it DID fail, hopefully the material completely incinerated and didnt jus fall in his cylinder. There is also a chance that it was pushed out exhaust port too.

I wd replace all the plugs.

 

good looks on the mms pic luke!!!

yeah, i never seen anythin like that.

Hmmmmmmm....after lookin at the pic, im stumped man. i mean there is nuttin left on the head...even the tip gone. I think we can all agree that all the iridium parts are gone. either the iridium all fell off at once or the material melted away. there is defintely evidence of burned material around the head of the plug.

I agree with luke...it must have fallen off. I dont think it was completely incinerated Use the magnet and try to fish it out. Hopefully combustion process pushed it out the exaust port. The parts are small enough it prolly blew right out of the muffker

 

The knocking your hearing is likely the 1" of electrode your missing from the spark plug. Hopefully you havent holed your piston or head yet. aluminum cylider is at high risk as well.

I doubt iridium is magnetic (ferrous), and we all know copper isnt. Put that piston at the verry bottom and look inside. I dont have high hopes with this one.

 

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Looking at the dings on the exposed part of the plug I can only imagine all the aluminum of the engine.

 

I put another good spark plug in there and the knocking still persist, but it was hitting alright. I am sure that it will need to be replaced. My good friend (mechanic) said that it was a one in a million thing to happen.

I was so excited for hitting 200k miles a few months ago and now It's all but dead at 207k. I can't even say it was my fault either. THAT is what bothers me.

I'm gonna be opening it up today and tomorrow. I will definitely let you all know what I find. This could possibly be a learning experience for all.

 

Good reason to buy coppers and replace once a year.

 

Well, spark plugs are suppose to last more than a year. The box on the Iridium says rated for 60-80k miles and whatnot. I think It's just a freak thing to happen.

 

Redardless of the mileage rating, sparkplugs work in a hellish invironment. I wouldn't leave them in my motor over a year without at least checking them.

 

Wow just wow. Time for a new motor unfortunetly, but may as well check compression now. Know any one with a camera scope?

 

The crappy part is that I checked them about 3 weeks ago and they looked great.

EDIT: On a side note, I took the rest of the plugs out today and they look pretty damn good. Just for ****s and grins, I'll post them up along side the failed one when I get some time.

 

You need to use a borescope to inspect the condition of said parts (piston, valves, etc.). Most bore scopes come with the tiny mirror to see things at a 90deg angle.

If I was closer, I would lend you my borescope.

 

Its iridium. I expect them to ALL still look good. Its melting point is so much higher than copper and plat they plugs should look a lil worn but all of them shd be good. I really think u jus got hold of a bad one.

Im not one to start fires but i wd be remiss if I didnt at least state this: U may want to contact NGK. That plug was defective. Even if the iridium completely burned off, the base material still should have held. U may have a case.

I dont think i wd wait every 5 -6 yrs to replace plugs. Nor do i want to replace plugs every year. I say replace 2-3 yrs with plats.

 

There is a remote possiblity that a hosed rod bearing, broken piston, or stretched rod allowed piston contact with the plug. As I said it would be remote, however there is the possibilty that it wasnt the plugs fault.

 

UPDATE.

By the grace of god, my car has been running for about a month making NO NOISE whatsoever.

I changed the spark plugs out and put in some New Denso Iridium IK20's and after letting the car idle for about 5 minutes, the knocking completely stopped. Did it go out the exhaust? No idea.

My mechanic says he can't believe it stopped knocking, but I do know that the engine runs great now and I'm getting way better gas mileage than I ever have. The car runs like nothing ever happened. Let's hope it will stay this way!

Thank you god!

 

YEAR UPDATE: I'm STILL driving the same car with the same engine and just turned over 230k miles yesterday. The knocking NEVER came back and my car runs fantastic. I would also recommend to anyone the Denso IK20 Iridium plugs that I replaced my old NGKs with.

My intent was not to resurrect an old thread, but just to show how beastly the VQ30 is. Well, at least mine.

 

That almkst makes me wana keep my motor in. I have 233k and it runs good but i want that 3.5

 

I still cant believe how the knocking noise went away.

 

Where do you guys recommend buying the spark plugs (good price?), how many are needed for a 97? Are NGK the best?

 

All north American maximas are 6 cylinder. After shipping any savings from an online vendor will be null. Go you your local parts supplier and get copper or plat NGKs, iridium is just overkill for a 4th Gen.

 

Good tip when you are changing plugs: Loosen them about an 1/8th of a turn, put the coils back on, start it up, and rev the engine a good 2 or 3 times. It will suck the carbon up that was built up around the plug so you wont grind it into the threads when you put the new ones on. Also, tighten them at first by hand so you don't cross thread by accident. Lastly, DONT OVERTIGHTEN THEM!! Picture what 5 lbs feels like in your hands and use that as a guide.