ok so this is what happened, i floored it and it sounded like it hit the rev limiter then a loud screeching sound then it stopped and i kept driving normal without flooring it anymore and a loud hissing sounded started when the boost came up kinda like when the y pipe leaks. an hour latr i open up the hood and noticed it had puked some coolant and i went out for a drive and everything was fine except for the hissing sound that could be heard when the boost came up to about 20psi....then while driving at about 50mph a loud banging like sound started on the driver side of the engine so i pulled over and shut the engine off. then i turn it back on truck idles fine but theres a LOUD banging noise coming from the engine, sounds like its coming from the driver side, i took the valve cover off expecting to see a broken rocker arm or sumthing but no. has anyone ever experienced this? maybe i bent a valve? broken piston? sounds like a gasser engine with a spark plug removed, not unplugged REMOVED...sounds bad hope it can be fixed

 

Internal damage.....requires a tear down to determine extent of damage......

 

Hissing sounds like you have a hole in a CAC boot, or blew a CAC boot off.
Knocking? Its possible you lost an injector. I've already seen more than 4 or 5 of these that sounds like the motor is toast and was a bad injector or 2.

Have you scanned it?
Any smoke? Color?

 

pulling my engine 1st thing in the morning hope all goes well

 

it would be nice if it were just an injector

 

Bent valve, says I.

 

i hope its not borken piston...about to start tear down

 

Pull the air intake and check the turbo impeller to see if you broke a shaft/turbo housing. That's at least a simple start. I'm thinking bent connecting rod worst case scenario. It's actually happened a LOT on some STOCK nontuned trucks here lately. I'm talking rods throught the block catastrophic. FWIW--my motor had a rod get bent from HIGH rpm's just enough that the rod was "tapping" the crank throw every time it came around. It sounded like a piece of sheet metal rubbing on the gear teeth around the torque convertor though. Not the banging you are describing.

 

the 1st sound i heard was kinda like what u describe the was at about 4k rpms and the banging sound started after an hour or so, it still idled fine except for the banging. will a bent rod or broken piston allow the truck to have a smooth idle?

 

My truck idled and ran "fine" but it was annoying as hell. Took a while to even find what it was after the motor was out and torn down. The rod was only bent a VERY small amount. I wouldn't think that would be your case though.

 

check for a kicked rocker or bent push tube

 

so i pulled the engine there was a broken rocker and a bent pushrod, theres a small scratch on the piston where the valve made contact, hope nothing else is wrong im have the heads checked at the machine shop

 

it would have been far cheeper to replace the bent push tube and rocker before tearing it down. seen it befor had lot of luck fixem them too.
hmmmm see post 11

 

Cheezit if they would only listen, things could be so much easyer

 

I'm willing to bet that the valves are just fine. I've seen a little valve to piston contact before with no apparent issues--LOL.