P0300-2 code, missfire = bent plug

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Sep 27, 2010 | 12:44 AM

AZZ-KIKR

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Melting Slicks

Joined: Mar 2007

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From: Always In Front, Colorado

P0300-2 code, missfire = bent plug

After a brief 3 rd gear pull to 100, once I let off a begun cursing speed, I get a SES bilking light and then can tell that the car is running rough..

Fast forward a week, limped it up to auto parts store to get the cyl that was causing the misfire, which was #2.. So, I pulled the plug and found this...

Crappy Utah approved photos below..

So, I then pulled the rest of the plugs, all of which looked perfect.. pulled the valve cover looking for broken spring and everything looked intact, no broken springs..

So, now I am wondering what caused this.. Engine is a stock ls6 with A&A Stage II P-1 running 8.5 psi with meth..

So, A. either something went through the cylinder (piece of land, piston, junk, etc) or can this be caused by heat under boost? Plugs are about 3 years old..

At this time I am thinking about pulling the head to look at the pistons, etc, and see if I can find anything.. Anyone else have this and found nothing wrong or something that would cause this?

New plugs are in, runs just fine (just around the block), but this has me concerned.

Sep 27, 2010 | 03:43 AM

BLOWNBLUEZ06

Tech Contributor

Joined: Apr 2007

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From: Forney Texas

Looks like it's covered in oil. I've heard of detonation causing it. Seen ring lands and other objects digested by the motor cause it too. Would be a great time to have a fiber optic camera to look in the cylinder. Let us know what you find.

Sep 27, 2010 | 08:58 AM

TheCartel

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From: 918 OK

I wouldn't be driving it. I'd find a camera, or pull that head for sure.

Sep 27, 2010 | 09:07 AM

396375

Melting Slicks

Joined: Nov 2007

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From: Niagara Falls NY

St. Jude Donor '08-'09

Quote:

Originally Posted by BLOWNBLUEZ06

Usually it's a piece of the piston after the car has detonated that causes the plug to close up like this.I've seen it so bad that it actually blew the ground strap right off.Did you hear the car detonate and was there any chance you were low on fuel or meth?I would pull the head.You may get away with replacing a piston in the car if you are tight for cash.If it was detonation I would be checking your fuel pump and injectors.Any good diesel shop can flow the injectors.No matter what you do you have to find out why it happened or it will happen again and may be worse next time.I saw a cheap fibre optic camera on "Cool Tools" the other night.I don't know if the head was small enough for a plug hole.Check their site.Good time to forge the bottom end.You could fix the one cylinder and sell your short and buy a new forged one.There is one in the classified section for $2500 that looks like a good deal.
Good luck.

Sep 27, 2010 | 10:51 AM

AZZ-KIKR

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Melting Slicks

Joined: Mar 2007

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From: Always In Front, Colorado

Thanks for the info Guys.. I have a friend with a scope so we can look at the cylinder sometime this week. I felt no detonation, car is at 1/2 tank, same with meth.. Nothing out of the ordinary.. Maybe she's getting a bit tired.

Sep 28, 2010 | 02:57 PM

cobill1972

Instructor

Joined: Dec 2009

Posts: 124

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From: Littleton CO

Quote:

Originally Posted by Get Bit

I think its the driver thats old and tired not the car

Let me know when your going to come by and get the video stick it works pretty well. Worse case I have a ton of extra parts around here you are welcome to if you decide not to go forged yet.
I'll let you know how mine does as I plan on strapping it to the dyno sometime in the morning to see if she holds together and taking it to the track that afternoon

Let me know...
Bill

Sep 28, 2010 | 03:55 PM

user_name

Melting Slicks

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From: Houston

Well since you verified it didn't come from the top half of the motor my money is on it coming from the pistons/wrings like blownbluez06 indicated. That is unless the motor ingested something.

Sep 30, 2010 | 12:03 AM

AZZ-KIKR

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Melting Slicks

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From: Always In Front, Colorado

Thanks, guys and Bill! Have not done anything with it as I've been busy with work related stuff. Will probably look into it this weekend.

Let me know how you did on the dyno and track, Bill. I want to see that 10.xx slip!