I have a 3800 engine with the zzp M90 install on it along with headers and a CAI. After driving for about a week it started running terribly and i pulled the plugs and one looked like it was hit by a hammer. Now 2 weeks later it happened again with a different spark plug in the front row. What could be causing this?

 

What plugs are you running?

 

the first set was autolite 103s, then i replaced them with iridium plugs, i forget the brand. also i had a check engine light on, i replaced the cam pos. sensor which left the light on so the timing chain is done too, could that cause it?

 

I think Wiz needs a part no. so that he can check his books to see if you got the wrongdepth threads.

 

i think most of the guys that run smaller pulleys and stuff on their superchargers are running autolite 104's because they're the easiest to figure out, 103's may be too cold..but then again maybe they're not..i'm not familiar with your supercharger...BUT from what i've been told you do NOT want to run iridium or platnum plugs, for some reason you get too much kr when your running those, so you want to stick with the plain copper plugs

like if you look @ ngk the # of your plug stock is TR55GP (i'm not @ work right now, so i can't remember if there's a dash 1 after the part # or not, but what you want to go to is a TR65gp with the dash 1 if the stock # has a dash one, i will check when i get to work tommorrow, i personally like ngk more than autolite so thats the way i would go...

will post more tommorrow, but maybe someone will pipe up before i get a chance...i know there's some guyz on here that know a lot more about this stuff than me

 

You could have severe Pre-Ignition. Real bad! Critically bad.

 

How much knock (KR) do you usually have?

I'm pretty sure if the spark plug looks like that that you've fragged a piston (and another one later on). Even a poorly running engine can't physically damage plugs like that- I've seen them melt before, but if its been pyhsically crushed like that, it had to come from something hitting it. Autolite 103s won't hit the pistons- they are a correct plug for this engine, so it must be piston pieces hitting the plugs in question.

I hope its not the case, but every time I've seen someone post plugs that look like that on clubgp, it has ALWAYS been chipped off piston pieces.