Always getting knock Retard
Always getting knock Retard Hi
my friends Camaro SS
has a strange problem
he bought a rebuilt motor *short block* from a local guy here
built LS1 348ci set up for nitrous
Custom Nitrous Camshaft 228/230 571/573 LSA 114
Rest of the setup
ETP 215 62cc
FAST 102mm
102 bigmouth
headers
11.1 CP
3200stall
3.73 gears
The car is a good daily driver, it's tuned and sound great
and the mid range TQ is huge
But the problem is it doesn't stand timing, it has to be in the 17-18° in timing so it doesnīt sense Knock Retard in WOT and it doesnīt pull jack **** after 4500 rpms
AFR is 12.5 threw the band, but if you give it more timing it just KR, we tryed give it racegas but it didnīt change anything it just KR if we gave it more timing.
I think it isnīt false knock, because i can get KR out by going down in timing.
the car went at the track like this and it went 13.1@105
So the question is
What can be wrong here ?
could it be
1. the Camshaft is built this way
2. the camshaft is degreed wrong
3. something wrong whith tuning
???
Baezi
my friends Camaro SS
has a strange problem
he bought a rebuilt motor *short block* from a local guy here
built LS1 348ci set up for nitrous
Custom Nitrous Camshaft 228/230 571/573 LSA 114
Rest of the setup
ETP 215 62cc
FAST 102mm
102 bigmouth
headers
11.1 CP
3200stall
3.73 gears
The car is a good daily driver, it's tuned and sound great
and the mid range TQ is huge
But the problem is it doesn't stand timing, it has to be in the 17-18° in timing so it doesnīt sense Knock Retard in WOT and it doesnīt pull jack **** after 4500 rpms
AFR is 12.5 threw the band, but if you give it more timing it just KR, we tryed give it racegas but it didnīt change anything it just KR if we gave it more timing.
I think it isnīt false knock, because i can get KR out by going down in timing.
the car went at the track like this and it went 13.1@105
So the question is
What can be wrong here ?
could it be
1. the Camshaft is built this way
2. the camshaft is degreed wrong
3. something wrong whith tuning
???
Baezi
Joined: Aug 2007
Posts: 24,241
Likes: 89
From: Turnin' Wrenches Infractions: 005
This can be a big problem with the auto cars with aftermarket converters. I would think it was something that should be corrected in the tune. Also, the knock sensors have to be torqued properly for them to read right. Those would be the two things I look at first. The tuning info can be found in the PCM section.
On The Tree
Joined: May 2006
Posts: 137
Likes: 0
From: 60 mi SE of Melbourne, Australia
What are the knock sensor sensitivites set at in the tune? I dunno what OS you are using, but perhaps try to find the original settings for that car / model year and reflash those. If they are stock, decreasing sensitivity - to a point - might be the only remedy.
Are you hearing knock - using a stethoscope / earmufffs, or is it simply showing up KR on the tuning logs?
How aggressive are your KR tables for reducing timing?
Have you got enough fuel flow / injector?
Is there some mechanical issue that is causing false knock?
As you suggest, it may be camshaft related, although camshaft timing would not ordinarily cause knock / trigger knock sensors unless it is WAY out, would it?
Sorry if my queries have already been addressed.
FWIW - my car with those heads and a cam that has higher dynamic compression than the cam your mate has (all the mods in my sig), takes just under 25* timing up top.
Good luck with it.
BTW - great choice in the ETP215s!
cheers
Are you hearing knock - using a stethoscope / earmufffs, or is it simply showing up KR on the tuning logs?
How aggressive are your KR tables for reducing timing?
Have you got enough fuel flow / injector?
Is there some mechanical issue that is causing false knock?
As you suggest, it may be camshaft related, although camshaft timing would not ordinarily cause knock / trigger knock sensors unless it is WAY out, would it?
Sorry if my queries have already been addressed.
FWIW - my car with those heads and a cam that has higher dynamic compression than the cam your mate has (all the mods in my sig), takes just under 25* timing up top.
Good luck with it.
BTW - great choice in the ETP215s!
cheers
Last edited by macca33; Jul 11, 2011 at 11:17 PM.
What are the knock sensor sensitivites set at in the tune? I dunno what OS you are using, but perhaps try to find the original settings for that car / model year and reflash those. If they are stock, decreasing sensitivity - to a point - might be the only remedy.
It's set at stock
Are you hearing knock - using a stethoscope / earmufffs, or is it simply showing up KR on the tuning logs?
Not hearing knock no only showing KR in the log
How aggressive are your KR tables for reducing timing?
stock
Have you got enough fuel flow / injector?
they are LS7 injectors, but maby some settings are wrong, that was one idea i got
Is there some mechanical issue that is causing false knock?
the motor is new rebuilts and sounds fresh
As you suggest, it may be camshaft related, although camshaft timing would not ordinarily cause knock / trigger knock sensors unless it is WAY out, would it?
Sorry if my queries have already been addressed.
FWIW - my car with those heads and a cam that has higher dynamic compression than the cam your mate has (all the mods in my sig), takes just under 25* timing up top.
Good luck with it.
BTW - great choice in the ETP215s!
cheers
It's set at stock
Are you hearing knock - using a stethoscope / earmufffs, or is it simply showing up KR on the tuning logs?
Not hearing knock no only showing KR in the log
How aggressive are your KR tables for reducing timing?
stock
Have you got enough fuel flow / injector?
they are LS7 injectors, but maby some settings are wrong, that was one idea i got
Is there some mechanical issue that is causing false knock?
the motor is new rebuilts and sounds fresh
As you suggest, it may be camshaft related, although camshaft timing would not ordinarily cause knock / trigger knock sensors unless it is WAY out, would it?
Sorry if my queries have already been addressed.
FWIW - my car with those heads and a cam that has higher dynamic compression than the cam your mate has (all the mods in my sig), takes just under 25* timing up top.
Good luck with it.
BTW - great choice in the ETP215s!
cheers
thanks
Baezi
Trending Topics
Joined: Aug 2007
Posts: 24,241
Likes: 89
From: Turnin' Wrenches Infractions: 005
I don't remember the process for fixing it in the tune. Thats why I said its in the PCM section. You are gonna need to search around that section until you find one of the threads that tells you how to fix it.
LS1 Tech Stories
The Best V8 Stories One Small Block at Time
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
Coachbuilt N2A Anteros Is an LS2-Powered C6 Corvette In Italian Clothes
Verdad Gallardo
Awesome K5 Blazer Restomod Comes With C7 Corvette Power
Verdad Gallardo
10 Camaros You Should Never Buy
10 LS Engine Myths That Refuse to Die
Verdad Gallardo
The convertor is a good possibility but it could also be a bad harmonic dampener. What pulley is on the car? I have seen some of the cheap underdrive pulleys cause KR and swapping back to stock fixed it.
there was some problem whith flexplate, but it is fixed now, but still the KR
baezi
