05 CTS-V LS6 Valves Knocking
Thread Starter
Teching In
Joined: Oct 2018
Posts: 3
Likes: 0
From: Atlanta, GA
05 CTS-V LS6 Valves Knocking Howdy folks, I am new to the forum and did scour the archive threads looking for guidance, but basically my baby starts knocking (loudly) under load around 4k RPM. It is lightly modified, trans and drive train stuff, but nothing done to engine. It has nearly 100k on the odometer, but about a year ago it started this knocking.
I appreciate how impossible it is to diagnose over the Internet/forum, but basically I need some guidance on what to attack and figured, reading numerous other threads, that getting an HP Tuner and pulling the current data would be the start. It has no engine codes using my basic OBD2 scan tool, but I did have a local (and trusted) shop replace the knock sensor just in case (amongst the other mods). The guy at the shop was stumped (short of pulling the heads to take a look) and suggested I get my own "professional" tool, since I race it often.
So, I have done the small things, like de-carbonize, use 93 octane (always) and synthetic oil (always), fuel injector cleaner both Seafoam and Lucas. If the heads need to be-rebuilt, I am ok with doing some performance upgrades to the engine like new heads.
I am open to any and all suggestions including getting an HP Tuner (which one?) or another advanced scan/flash tool.
Many thanks!
Tim
I appreciate how impossible it is to diagnose over the Internet/forum, but basically I need some guidance on what to attack and figured, reading numerous other threads, that getting an HP Tuner and pulling the current data would be the start. It has no engine codes using my basic OBD2 scan tool, but I did have a local (and trusted) shop replace the knock sensor just in case (amongst the other mods). The guy at the shop was stumped (short of pulling the heads to take a look) and suggested I get my own "professional" tool, since I race it often.
So, I have done the small things, like de-carbonize, use 93 octane (always) and synthetic oil (always), fuel injector cleaner both Seafoam and Lucas. If the heads need to be-rebuilt, I am ok with doing some performance upgrades to the engine like new heads.
I am open to any and all suggestions including getting an HP Tuner (which one?) or another advanced scan/flash tool.
Many thanks!
Tim
I had bad knocks at 4500+ rpm too (LS1 2001 TA). For years. I had done "only" an airlid. When I put on long tubes, I took it for a professional tune. The tuner (Jeremy at FasterProms) was shocked how lean it was and "how much fuel he had to add to the tables". Now it runs fantastic all the way up to 6k. I don't know if my tune was "bad" from the factory, from the 1st owner, or even just my airlid did so much to mung up the A/F ratio.
Thread Starter
Teching In
Joined: Oct 2018
Posts: 3
Likes: 0
From: Atlanta, GA
Thank you Chris. Are the LS1 and LS6 similar? Do you think age had anything to do with your knocking in your case? Logically speaking, something that started with higher miles would allude me to think that it was a wear item or a slowly going bad sensor, hence my request to swap out the knock sensor. As for wear items, I have read everything from tappets to cam lobe wear to pitted valves, which would make sense but hard to tell without pulling the head covers or heads themselves. If I go that far, I may as well have them rebuilt or do some performance upgrades... Anyway, for another time we can talk performance upgrades.
Do you have a preference on scan/tuner tools/software???
Thanks for the quick response!
Tim
Do you have a preference on scan/tuner tools/software???
Thanks for the quick response!
Tim
Sorry I can't really say any more as what to look for. I only wanted to point out fuel map could be an issue, if maybe there was an upgrade that you did not mention. I'd go with knock sensors first too for parts. I use a wifi OBD2 transmitter and an iPhone app called DashCommand (Android version too I think). It has a lot of details (100s of sensors/data points if your car has them) and easy to use, but only reads codes it can't program. It can clear IIRC. In app purchase to unlock additional codes depending on the vehicle. I know on my car it can see knock sensors and misfires, and AF ratio. It was like $10 for the app and $20 for the obd2 adapter so a cheap way to start.
Trending Topics
LS1 Tech Stories
The Best V8 Stories One Small Block at Time
Gas Monkey Built a 6-Wheel Ferrari Testarossa With a Corvette LT4 Engine
Verdad Gallardo
7 Most Reliable High-Performance Engines GM Has Ever Built
Verdad Gallardo
Amazing '71 Camaro Restomod Is Modern Muscle Car Under the Skin
Verdad Gallardo
6 Common C5 Corvette Failures and What's Involved In Repairing Them
Pouria Savadkouei
Retro Modern Bandit Pontiac Trans AM Comes With Burt Reynolds' Autograph
Verdad Gallardo
Top 10 Greatest Cadillac V Series Performance Models Ever, Ranked
Pouria Savadkouei
Top 10 Most Powerful Chevy Trucks Ever Made!
Hennessey's New Supercharged Silverado ZR2 Has 700 HP
Verdad Gallardo
