Knock retard gurus, please step inside
Thread Starter
Registered User
Joined: Aug 2001
Posts: 202
From: St. Louis
Originally posted by Dan K
Jason,
I looked at the datamaster logs that you sent and e-mailed you back, but just thought I'd share what I found.
Your knock does not START at high rpm OR high map. 90% of the retard you see is in fuel trim cell 11, with rpm's at about 2800, map at about 65-70. Also throttle is between 1/4 and 1/3 (going by TPS %). Eventually you might get to a higher rpm or tps, but that is not where the knock starts.
Some of this is false knock and some of it is real.
If I were you I would track down the false knock and pull some timing out based on where the knock first starts in the logs and go from there.
Not sure what else to tell you, but I wish I could help more.
Jason,
I looked at the datamaster logs that you sent and e-mailed you back, but just thought I'd share what I found.
Your knock does not START at high rpm OR high map. 90% of the retard you see is in fuel trim cell 11, with rpm's at about 2800, map at about 65-70. Also throttle is between 1/4 and 1/3 (going by TPS %). Eventually you might get to a higher rpm or tps, but that is not where the knock starts.
Some of this is false knock and some of it is real.
If I were you I would track down the false knock and pull some timing out based on where the knock first starts in the logs and go from there.
Not sure what else to tell you, but I wish I could help more.
How did you determine which knock is real and false? I assumed running race fuel would rule out false knock since I still got very similar KR.
I appreciate the help!
Registered User
Joined: Feb 1999
Posts: 34
From: Fairfax, Virginia
The only thing I can add is to actually remove and reseat the knock sensor into the block, using as accurate a torque wrench as you can. I have seen a few cases where it was just a little too tight, and this caused it to be too "sensitive", setting off prematurely.
-Ernest
95 Z
-Ernest
95 Z
Registered User
Joined: Jul 2001
Posts: 1,009
From: so close I can taste it...
Originally posted by Tech
While driving I can bury the throttle and everything is fine until I hit 3k RPMs and BOOM a large spike. I get peak KR around this area. I've pulled timing from 3000+ PRM and higher MAP values (can't remember the exact number) without any change.
While driving I can bury the throttle and everything is fine until I hit 3k RPMs and BOOM a large spike. I get peak KR around this area. I've pulled timing from 3000+ PRM and higher MAP values (can't remember the exact number) without any change.
Again, the knock retard is coming in before 3000rpm...usually starts right at 2700rpm and about 60-70map.
Check the TPS though....
Thread Starter
Registered User
Joined: Aug 2001
Posts: 202
From: St. Louis
Originally posted by Dan K
You're saying "bury the throttle"....I don't see TPS get above 1.X volts ever. Nor does TPS% get much over 35ish. Have you checked that the TPS goes from the .65v closed at idle that you have to 4.25+ volts at wot? Does it go up linearly?
Again, the knock retard is coming in before 3000rpm...usually starts right at 2700rpm and about 60-70map.
Check the TPS though....
You're saying "bury the throttle"....I don't see TPS get above 1.X volts ever. Nor does TPS% get much over 35ish. Have you checked that the TPS goes from the .65v closed at idle that you have to 4.25+ volts at wot? Does it go up linearly?
Again, the knock retard is coming in before 3000rpm...usually starts right at 2700rpm and about 60-70map.
Check the TPS though....
The reason why you didn't see 100% TPS is because the car had the blower on it and it hadn't been tuned. Like I mentioned, those were the only files I had at work. I'll gladly send you some updated ones tomorrow.
Thread
Thread Starter
Forum
Replies
Last Post
Formula Steve
LT1 Based Engine Tech
45
Sep 19, 2023 08:31 AM