I was driving on the highway and heard a pop or knock, ran rough after that and got it back home a few km away. When I let it idle and popped the hood the #3(the #'s go left to right correct?) coil was bouncing slightly up and down and the 10mm bolt holding it down was loose. I turned off the car and checked it out. The coil was broken, seperated between the box-like top half and the rubber boot that comes down to make contact with the plug. The rubber boot was split in 3, and the metal sleeve the spark plug toutches was slightly bent in/apart. The spark plug came right out when I pulled the coil, the bottom 2 threads were striped but not the rest except for a flat spot on one thread half-way up. The gap was'nt there anymore and it almost looked like it had been struck on the little arm piece that arc's with the tip. Thing is I tried to briefly start and idle it for maybe 15 seconds and it ran. Stange part for me atleast is that it was blowing air from the spark plug hole suggesting the piston could still move up and down and create compression.

How could the spark plug have been shot out? Is there any other explanation other than my wrist pin somehow partially failed enough to allow the piston to contact the spark plug and do the damage but somehow still be intact enough to generate compression? Engine knock couldn't do this to the plug and coil could it?

It's also worth noting that this is a used engine I put in to replace my blown motor in november. The new motor I believe the intake manifold's laminova cores are leaking because I was never able to fully purge the air from the intercooler line and the car made a little white smoke ocassionally after letting off the gas after being under boost at first when it was put in but the main coolant res never dropped, and when I stopped filling my i/c line, the smoke stopped the next day. I run the car nice and easy and in sub-freezing temps for winter so I figured I'd take the manifold off my old engine and put it on before spring when the weather starts heating up again.

Back to the main issue, I don't want to run it till I can confirm the wrist pin isn't halfway failed and then have it let go and come through the head. Is that even possible for the piston to strike the spark plug and still be able to make compression? If it's not possible, what other possible causes could I be looking at? Thanks for the help everybody.

 

There seem to be a few guys that have experienced the same thing,thoughts were that the spark plug actually came loose and when threaded out far enough blew the last few threads out.

If your wrist pins were loose I would think you would of heard knocking noises before the plug blew out.

Throw up some pics of the plug etc,would like to see it,show the end of the plug with a close up.

 

Here's the pics


By midnightnb at 2012-01-31


By midnightnb at 2012-01-31


By midnightnb at 2012-01-31

I'm hoping your right, its just when I saw the tip of the plug it got me a little worried.

**edit**
I don't have my code reader with me so I can't check what popped this time, but it's worth noting I had a P0303 Cylinder 3 Misfire Detected -PCM code pop up back in december but I cleared it and it never came back... Although if it was backing off before it popped out that could explain something. Just want to make sure before I even think of attempting to go to work with this. I only work like 3km(2 miles) away on base, unless I have to go out to camp petersville and go back to the training area, then it's about 37km(21miles) in which case I don't know if I'd want to limp it there. I know it'll burn fuel like a pig but if its only the threads for the plug then I'd rather drive then walk to base in the cold, it was -15c this morning(around 0f), but if I'm gonna hurt my engine then I'll have to man-up and just walk, lol.

 

The plug looks like you were getting lots of blow by,so it probably wasn't in tight.
But it would be your call on what to do,if you put another plug in there make sure you get it in right with those buggered thread it will be easy to cross thread.( maybe run a proper tap in to fix up the threads first)
Also if the cylinder was to hit the plug and knock it out would you not think that it would of took all the threads with it?

 

dat ***** fucked up son! g/l

 

What shitty ass plugs are those? Look like Autolites, maybe Champions. Both are crap though. NGK Copper plugs. Nuff Said. BKR7E. That doesn't have anything to do with your problem though.

Your problem is that the Spark Plugs weren't torqued properly... and were then able to loosen. Have you checked the other plugs? I would. I had a friend who had a similar thing happen (on a highway 500miles from home)... sure enough, his other 3 plugs were loose as a good, as well.

Read sections 1-3. Learn them and follow them: Spark Plug Installation Instructions

 

i have a cat inefficiency bank 1 code. after 50-100 miles a P0300 code pops up(random multiple misfires) when i clear them out the P0420 comes back on after about 40 miles. in the higher RPMs its starts spitting like i hit the rev limiter. can anybody point me in the right direction?

 

if its not letting you rev up like it should and bogs up when u hit around 5 or 6k then i would suggest you check your downpipe... it may be a blown cat

 

maybe the person who installed the plugs was scared of de-threading the head so they were not tightened properly (engine vibrations will cause it to bolt off over time)

 

a few months ago i got in to an accident and bent the bottom of the downpipe. the mechanic said it wouldn't effect my car since it wasn't crushed. thats when it started throwing codes. i asked him about the codes and he said it had nothing to do with the accident.

 

REPLACE the DP ....its not letting exhaust gases flow properly... dumb mechanic lol

 

this is whats happening.... you rev up your car and engine produces more exhaust gases right? and since your DP has a smaller diameter now that its crushed, its having a hard time pushing all the gasses out so your car is being forced and one of the 02 sensors is reading that you have bad flow. thats what i think

 

Depends on how bad the dent is. Sounds more like a clogged cat. GM should replace it for free. The Emissions warranty is quite long.

fify

 

the Cat is warrantied till 130k miles, so yes go check if they will replace it :

 

Don't see em replacing it if it has a big dent in it

 

If the piping itself is dented... it doesn't matter... the piping isn't what is covered... the CAT is what is covered.

 

i'm going the other route. i got a hahn full exhaust. waiting on the header though. they said they have to order the material. hopefully 3" will open it up a little.

 

don't need 3" s/c...have fun with the 600 dollar exhaust that comes with the muffler hanging a foot below the bumper lol.

 

When I push my 07 I have the same issue..i've had my aftermarket dp for about 70,000miles now could it get clogged in that time? Is there anyway to clear it out instead of buying a new one?

 

It could be clogged... or you could have a different issue.

If you want to punch the cat out... take the downpipe off... and then follow one of the many different procedures for emptying the cat. Google it. Most just punch it out with a looooong pry bar, though.

 

If I punch out my cat I don't know if I will be able to pass inspection?...or throw a code?....there is nothing I hate more then my CEL coming on haha

 

I don't know how thorough their inspection is. If they do a sniffer test, its quite possible that you'll fail. And yeah, it'll throw a code. Get tuned and the code can be deleted.

 

cool thanks for the input...I have a few ways to clean the high performance cat before I go removing it.