I had a problem a while back which probably let some debris into the #6 cylinder, black plastic and maybe some metal (from the busted up ignition coil). The problem was caused by a very bad misfire on the #6 cylinder, which shot the spark plug out of the engine. I got any remaining debris out of the #6 cylinder with a vacuum when I re-threaded the hole. From what I could see through the spark plug hole, the top of the cylinder looked like clean metal, but not shiny.

Since then, I have had constant pinging/knocking, but the engine feels like it is running ok. However, it feels like it may be just a little weak on power, but not much as it is barely noticeable.

At that time, I changed the plugs. About a week later I checked one of the plugs and the base looked like it had been painted with gloss black spray-paint.

A little later, when the car was at the stealership, I was told that the mechanic said that it was a "really bad noise" and he was scared to drive it.

Just recently I checked for codes and, not surprisingly, the only code I got was the KS. I am fairly confident that the KS code is a result of the problem, not the cause.

Is it likely that this is caused by the timing chain needing adjustment?

Could this be a result of melted plastic coating part of the inside of the cylinder staying hot and causing pre-ignition? Would Seafoam help this?

Could any of the debris have traveled through the engine to a different cylinder, or into the valves?

I am open to any thoughts or suggestions.

This car is a 96 GLE only has 135K miles, so I would hate to have to get rid of it and go back to my 95 GXE.

Thanks,
Rob.

P.S. I was looking at the "Just how harmful is knocking?" thread, but I didn't want to hijack it. It did get me more worried about this though.

 

To put it short I think you melted down a piston. I would say that the gloss black stuff is oil. The lost in power is the inefficiency of the lost cylinder compression. I would go ahead and start looking on Ebay for another engine. Sorry to hear about that. I cringe when I read posts of people that drop metal objects into the compression chamber. http://www.streetrodstuff.com/Articl...ne/Detonation/

 

yeah, sorry to say it but it sounds like it did some damage to the piston/rings/cylinder/head or valves....do a compression check to be sure.

 

You can also check www.car-part.com for an engine, or an org'er just put one up for sale (in the NY/LI area) - check the 4th Gen classifieds.

 

here's one from the classifieds...

http://forums.maxima.org/showthread.php?t=430716

 

I appreciate the links and pointing me to someone who has an engine for sale.

After reading about all this, it appears that I have detonation going on. The car feels fine, and the noise is not that loud (I can't hear it in the car with the windows up, or driving with the windows down). I only hear it if I am outside the car, or next to something that reflects the sound (like stopping at a light next to a jersey wall).

I am really looking for a way to stop the detonation that is going on to prevent further damage.

Is this possible? Could it be the timing chain? Any other suggestions?

Thanks!

 

Bump...

Still need help stopping detonation. I am going to try to boost the octane with additives, and I might even try the acetone trick talked about in some other threads.

Could using the wrong spark plug be a cause of detonation???