C4 Tech/Performance L98 Corvette and LT1 Corvette Technical Info, Internal Engine, External Engine

Knock Counts

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Old Sep 24, 2024 | 08:52 AM
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Default Knock Counts

When data logging, Is it normal to get 3600+ knock counts with zero degree knock retard? Thanks
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Old Sep 24, 2024 | 10:09 AM
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Is your car stock? What year?

Sometimes with aftermarket modifications like roller rockers, headers, more aggressive cams, etc... things can get a little noisier and the knock sensor will pick that up and start recording knock counts (even if it doesn't get to the point of retarding timing)

Also an incorrect sensor can cause it. Knock sensors are tuned for particular engines (i.e.. 305 vs 350 for example).

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Old Sep 24, 2024 | 10:44 AM
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Originally Posted by TheKodiak
When data logging, Is it normal to get 3600+ knock counts with zero degree knock retard? Thanks
It's feasible. What's the MAP reading during all the zero degree retard operation?
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Old Sep 24, 2024 | 03:46 PM
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It's a '96 LT1. Roller rockers and 52mmTB, are the only major mods done by the PO. During idle, I get 2.4K knocks, 0 knock retard. Should I only be concerned if I get knock retard?


Originally Posted by ULTM8Z
Is your car stock? What year?

Sometimes with aftermarket modifications like roller rockers, headers, more aggressive cams, etc... things can get a little noisier and the knock sensor will pick that up and start recording knock counts (even if it doesn't get to the point of retarding timing)

Also an incorrect sensor can cause it. Knock sensors are tuned for particular engines (i.e.. 305 vs 350 for example).
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Old Sep 24, 2024 | 03:56 PM
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During idle and cruising, 47.97 Kpa, but at WOT it's 52.4 Kpa.



Originally Posted by 69427
It's feasible. What's the MAP reading during all the zero degree retard operation?
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Old Sep 24, 2024 | 04:08 PM
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Originally Posted by TheKodiak
It's a '96 LT1. Roller rockers and 52mmTB, are the only major mods done by the PO. During idle, I get 2.4K knocks, 0 knock retard. Should I only be concerned if I get knock retard?
Assuming your knock sensor is not malfunctioning and is correct for the car, then I would likely chalk it up to false knock due to the roller rocker noise.

Questions about real/false knock are common on thirdgen.org. Couple of sample threads below... the first one is mine, where I was troubleshooting what I determined to be mostly false knock. But if you search you'll find tons of threads. Granted they're all about Gen1 small blocks, but the logic and diagnostics are largely going to be the same.

https://www.thirdgen.org/forums/diy-...tard-real.html

https://www.thirdgen.org/forums/tpi/...retarding.html



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Old Sep 24, 2024 | 04:48 PM
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I ran across this awhile back. I read don't worry about the counts only the knock retard. The counts start at 0 and go up to 60k or so on a loop. Looking at a few of my logs I noticed my counts went from 79 to 12k before I turned the key to start the engine. It stays at the 12k through the log unless you get spark retard at which it may go up 50 points. It also depends on where the log starts in the loop. Another started at 700 counts and remained there until I shut the car off and it climbed to 60k. I did notice couple times the count increased 40 or so and there was no knock retard. Must be the norm, 1993 lt1.
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Old Sep 24, 2024 | 06:27 PM
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I wonder if I could use knock sensors from a '96 LT4. I would probably need a new ecu, or am I off? Thanks a millions Gents
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Old Sep 24, 2024 | 06:32 PM
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I wouldn't introduce more variables into the mix. I'd ensure you have a genuine GM knock sensor for your vehicle. In that thread I linked to, I had to do that in order to solve my issue.
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Old Sep 24, 2024 | 07:21 PM
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Originally Posted by TheKodiak
I wonder if I could use knock sensors from a '96 LT4. I would probably need a new ecu, or am I off? Thanks a millions Gents
I believe the knock sensors are the same lt1/lt4. It was the lt4 knock module everyone used.
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Old Sep 24, 2024 | 09:42 PM
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Originally Posted by TheKodiak
I wonder if I could use knock sensors from a '96 LT4. I would probably need a new ecu, or am I off? Thanks a millions Gents
Using an LT4 knock module was standard practice when putting rollers into a 1996 LT1, either that, or tuning the LT1 one to be less sensitive.

use this as a search term
how to tune a 1996 lt1 knock module to be less sensitive
This is a LT4 knock module. I searched for months before I found one at a reasonable cost.

https://www.garretttuning.com/produc...DbEV_RgBNDIw3w

Last edited by drcook; Sep 24, 2024 at 10:34 PM. Reason: corrected terminology
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Old Sep 25, 2024 | 07:33 AM
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In a nutshell, it could be a false reading is what I gathered. My MAP readings look good, plus I have no knock retard, but my egr has been deleted. Shouldn't the LT4 module help "quite" things down? (I got confused between the module vs knock senor). As far a stock knock sensors, I'm more than 100% sure they're the originals, but I'll check anyways. The car was badly neglected, when I got it.

Originally Posted by ULTM8Z
I wouldn't introduce more variables into the mix. I'd ensure you have a genuine GM knock sensor for your vehicle. In that thread I linked to, I had to do that in order to solve my issue.

Last edited by TheKodiak; Sep 25, 2024 at 07:41 AM.
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