I have a 2003 LB7 motor that has a knock in the #7 or 8 cylinder, and it is blowing black smoke, still runs good, but knocks. I pulled the pan on the motor there are no metal shavings whatsoever in the pan, Not sure what it is? I was told if it was an injector tip its possible but im stumped? any ideas???

 

Sounds like an injector related issue. Done any modifications, such as a programmer or module??

 

No mods, i suppose i can pull the injectors and look them over next...

 

If you have a tech 2, efi live, ppe, quad stealth 2, predator tuners you can check the balance rates on the injectors

 

Possible he blew the tip on one or more of the injector nozzles??

 

the way it sounds its a injector problem. we hace alot of lb7 duramaxs come into the shop with injector problems. there warrantyed up to 200,00 miles..

 

i would take the truck into the shop and get some new injectors

 

sounds like new injectors are in the near future.

 

Gm has a warrantie of 200,000 miles or 7 years i would take it in and have it done before your warrantie runs out.

 

If this is the motor for the 70 Chev conversion, would GM still honor the warranty on just the motor?