Swapped Gen 3 Truck Knocking Like Hell !

well Guys
i have Tuned Several Cars
Several Trucks
Supercharged
Nitrous and many many many Cars
Clean Score ! havnt Break Any Engine

i will Post 2 photo's for Different Cars
and i would like Peolpe to tell me if im Wrong or not !

this is a Car 2 Tuners have Tuned it
and says there is no KNOCK
when i enabled all sensors in the car ,, it start showing me KR
in the 1st Run before Fixing the CAR
i had 360 RWHP on dyno jet
After few Weeks Fixing the Car ,, With the SAME Tune
SAME Timing ,,, the Car jumped to 490 RWHP on SAME dyno

Car is Zo6 2008 ,,,
this is a Gen 3 Thread ,, now i will Replay With the GEN 3 Car ISSUE that i will like People To Comment on it

now this is the GEN Truck
Silverado 2000
Swapped to 5.3 Engine
Questions i asked the customer
what is the ENGINE ? 5.3
What mods ? i dont know
Heads Cam ? what are they ? I dont know
what is the engine condition ? i dont know

its just a father bought a car for his Son and they dont know anything in the car

1st day on dyno ,, i had a KR and the fuel was Leaning up
Fuel pump Was Very poor

Changed the Fuel pump ,, AFR has played it between 11.9 Up to 12.9
Timing between 20 Down to 14

Still having a Knock in the Car !

after that send the Car to a Friend to see the car ( the one who Fixed the ZO6 )

he didnt know whats the issue ,, another Tuner Looked at it ( instead of sending the Car back to me to Re-check it )

he Tuned it ,, and he said there is no Knock !

now from your experience guys ,, Could this Knock be a False Knock ?

becuase i had changed the Fuel for the Car from 91 octane to 93 octane ,, and nothing Changed ,, Lowerd Timing same issue ,, for me looked like Mechanical issue ( Rocker arm Load _ Valve issue _ 5.3 engine with 4.8 heads ! )
dunno ,, any comments ? ides ?
because they made me look Stupid infront of the customer

thanks

Well. I'm not that experienced, but...

- find out if the knock always comes at the same RPM even if you remove timing a lot, then it probably is a some sort of mechanical-related noise
- aftermarket valvetrain (& pushrod) combinations can be noisy and thus introduce false knock

If possible, do some scans with perfectly stock vechiles. As an example, I've seen stock C5's remove timing but not really knocking.

Finally, use proper equipment to listen the engine (I guess you do that, but just as a reminder for casual reader).

these motors are bad about showing knock when there is none ..the knock sensor in these motors and in the tune are super sensitive ..i just listen to the motor for knock under load if none i turn down the sensor in the tune .this has been imo thorn in the side on these truck engine .hth

If they are under the intake....
Check the knock sensors and harness to them. Chances are very good they are corroded and needing replacing. Same with the harness.

the 1st thread is Zo6
is was Real Knock
Rocker arm load

the second car ,,, i guess the guy will break the engine
thanks for replay guys