2017 CTSV-A Love Story....

[L8rt8r]

Purchased a 2017 V with 44k on the clock in Dec. of '19. Mods...Whipple 2.9, Meth, Pulley's 3.25 up and 9.1 down. Made 15 psi.
Mistake #1-Didnt get a comp or leak down test. While the test drive was uneventful, after purchase, the stumbling and bumbling started. Flashing CEL... Got my tuner out when I got home and damn if it wasnt misfiring everywhere but not enough to through P codes.
Took it to N----- Speed in Richmond where after Leak Down -we had likely piston ring failure. Caveat Emptor. I should name this car Christine 'cause it's going to kill me....
Beautiful, unique car, I voted to go for the rebuild. Months went by due to Covid. Torn down to block, all good. Built it back up with what I hoped would add to a great platform:
Cam motion custom grind 5150 cam
LS7 rocker arm
comp cam HP fuel pump
New GM LT phaser bolt
Katech c5r timing chain
Cam motion block off plugs
BT racing valve springs
GM Lifter guide plates and bolts
Johnson lifters
Tooley rods
ARP bolt kits
Tooley trunion roller upgrade
Aux fuel pump
NGK LTR 7IX-11 plugs
Protect a boots
DSX Flex
Cordes expansion tank
Mighty Mouse Catch can
Kooks Headers/Borla exhaust

Refreshed the heads and Whipple.
E-85 tune HP @853hp
No more Meth....told that was the cause. Given the busted Piston as proof.

Drive home 8 months later flashing CEL at steady highway speed with no known issues at light load and only around the 70-75mph mark. BUT no stumbling or bumbling....drives fine. Shop takes it back for a week and says its the O2 sensors and rich fuel. Nothing to worry about.

Well I'm worried after break in and a long trip with multiple flashing CEL at that same steady low throttle 70-75 mph. I hooked up the tuner and misfires sitting in the garage at idle an light throttle (which hangs and 93 octane idle is too high but that's another issue)

Would never know an issue sans the light and the tuner. But that aint right. I did the proper break in with the Brad Penn oil as directed by them.

Here's a small shot of what's up. PS-Never replaced the coils... Appreciate any thoughts on what might be tune issues/possible try's before trailering to another shop.
Thanks, Matt
Attachment 111883ctsv_post_rebuild_idle_test.hpt

[01SLPSSM6]

Misfire settings are stock, with a bigger camshaft installed, the misfire monitor settings need to be raised. Dont max them out, you still need to be able see when a cylinder is actually misfiring, no real way to tune them that i am aware of, but start increasing them until you are not seeing any misfires. Its running on MAF only, the torque model is not going to work correctly left in just MAF only, the VVE needs to be tuned and enabled. What fuel pump lobe does the cam have? I would recommend taking the car to someone who knows what they are doing with the Gen 5 platform. You have a lot of money invested, take it someone who can calibrate the car right the way.

[L8rt8r]

Thanks for taking the time to review and respond. It means more than you know. I'll follow the adjustments you called out and post how it goes. To your question, its a 33% fuel lobe and appreciate any further direction you're willing to offer on that topic.... I think you're absolutely right, I've seen enough shortcuts taken elsewhere in the tune that tell me an experienced gen v tuner is the way to go. Your review confirmed they wanted it running enough to get out the door and I'm more convinced than ever no true data logging took place. Thanks again,
Matt