Unexplained knock retard.
Thread Starter
Launching!
Joined: Oct 2003
Posts: 248
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Unexplained knock retard. I have done two WOT runs where the scanmaster has recorded a knock retard of 10 and 12 degrees. Other times whenever I take off from a stop the scanmaster starts to read a knock retard under very light throttle conditions and it goes up as I give the car more throttle (0.1 to about 1.8 degrees of retard). The odd thing is that some days the scanmaster will record 0 knock retard even under WOT. At first I thought it may be because the engine might be running to cold (160 T-Stat) but I know for a fact when the scanmaster recorded the 10 degrees of retard at WOT my LT1 was at operating temps. Any input on the subject would be appreciated.
Thanks
Thanks
TECH Apprentice
Joined: Jun 2004
Posts: 312
Likes: 0
From: Romeoville, IL
heh I never knew my car had false knock untill I bought my scanmaster. What a great investment.
Anyway, dude I have the same issues you have. I think mine is because of my loud *** exhaust. But heck all I know it could be a lifter tick.
The best way to test to see if it is real knock is to try running some race gas in her. Maybe like half a tank of 100 octane. If the problem goes away, then you know its the fuel. If it doesn't go away, and you dont have any loud valvetrain noise or exhaust leaks, then it could be a fualty knock sensor. There is a huge post about this on cz28.com on the lt1 forum.
Good luck in tracking it down. I'm going nuts. I think I'm just going to have someone disable the knock retard on mine, cause its robbing power.
Mike
Anyway, dude I have the same issues you have. I think mine is because of my loud *** exhaust. But heck all I know it could be a lifter tick.
The best way to test to see if it is real knock is to try running some race gas in her. Maybe like half a tank of 100 octane. If the problem goes away, then you know its the fuel. If it doesn't go away, and you dont have any loud valvetrain noise or exhaust leaks, then it could be a fualty knock sensor. There is a huge post about this on cz28.com on the lt1 forum.
Good luck in tracking it down. I'm going nuts. I think I'm just going to have someone disable the knock retard on mine, cause its robbing power.
Mike
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Joined: Nov 2001
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From: LT1 land...the "409" of the 90s!
we fixed 90% of our Knock issues by scaling the decay tables by .75 
Then we zero'd all the low octain tables. Once the car would go into low octain mode there was ALWAYS some knock retard. Now there is only retard when we get real knock 
This is on a 12.5 to 1 engine running oxigenated 92 octain.
Then we zero'd all the low octain tables. Once the car would go into low octain mode there was ALWAYS some knock retard. Now there is only retard when we get real knock This is on a 12.5 to 1 engine running oxigenated 92 octain.
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Originally Posted by TwoFast4Lv
we fixed 90% of our Knock issues by scaling the decay tables by .75 Then we zero'd all the low octain tables. Once the car would go into low octain mode there was ALWAYS some knock retard. Now there is only retard when we get real knock
This is on a 12.5 to 1 engine running oxigenated 92 octain.
Then we zero'd all the low octain tables. Once the car would go into low octain mode there was ALWAYS some knock retard. Now there is only retard when we get real knock This is on a 12.5 to 1 engine running oxigenated 92 octain.
Now that's some real tuning right there. Otherwise I am with NoFear95, I just unplugged mine and turned it off. Motors ran for 40 years without them. 
