So I am remotely helping a buddy out with getting his Sierra tuned up. Its a 6.0L with a TVS1900 and a medium cam. Cam specs: .597 / .578 220* / 230* 115* lobe.
It came with an out of the box magnuson tune. Some problems the truck had from the get go...tossing misfire codes, and torque converter lock up issues. I made some changes starting from the magnuson tune. Scaled the injectors, a few other things. Adjusted VE and MAF to get it in the ball park. The truck was misfiring so much that I desensitized the misfire tables (which I hate doing, this cam should not need it) but we needed to get it tuned and it wouldn't run very well in safe mode of course.
We got part throttle tuning down pretty good, and then started working on PE and PE entry points. The more and more he drove the truck, the more and more knock became an issue...even at idle. The magnuson tune has more timing than stock, so I reduced timing back to stock and disabled burst knock (quite common for roots blower setups) to see if that would help...hell I went with even less timing than stock.
Knock is getting worse. The mechanic who did the install tore into it again, double checked the cam and valvetrain and looked for intake leaks. Cam was never degreed with a wheel but is dot to dot. Mechanic says everything checks out.
I have never seen a vehicle knock at idle if the fueling and timing are even remotely close to where it should be. Mechanic swears its not mechanical, so I am hoping I missed something in the tune and could use some extra eyes.
I am posting the current tune and a recent log. I have advised the owner not to drive it until we can get it figured out. Thanks for looking.