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Thread: Knock

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Posts: 1-9 of 9
2015-11-19 06:08:58
#1
Knock
Should I check or uncheck the ENABLE KNOCK SENSOR and ENABLE KNOCK ANALYSIS.?

From the start up calibration files I saw some tcd with check and uncheck position.

I am afraid of knock so I check both figuring it will save me from knock.
The problem is I get knock retard of 5 degree every time I hit 1psi.
I guess I hit invalid retard because knock sensor fails diagnostics.

Is my knock sensor bad when it fails diagnostics.?

When help section says cylinders voltages are initialized to 2.56v, is that knock sensor voltage?.
My knock voltage is 3.1v when I turn the ignition on


Thanks
2015-11-19 10:10:30
#2
Originally Posted by zurud
Should I check or uncheck the ENABLE KNOCK SENSOR and ENABLE KNOCK ANALYSIS.?

From the start up calibration files I saw some tcd with check and uncheck position.

I am afraid of knock so I check both figuring it will save me from knock.


If only Knock Sensor is enabled, you wont have any retardation of timing.
Knock Analysis needs to be enabled for the ECU to add/remove "Knock Trim"


The problem is I get knock retard of 5 degree every time I hit 1psi.
I guess I hit invalid retard because knock sensor fails diagnostics.


Reasons for false knock:
-Too sensitive limits
-Faulty sensor
-Engine mounts other than OEM rubber. Also broken engine mounts. Can be tuned around by adjusting limits


When help section says cylinders voltages are initialized to 2.56v, is that knock sensor voltage?.
My knock voltage is 3.1v when I turn the ignition on
Thanks


I don't have access to my tuning laptop atm, so I can't answer this. Maybe someone else can chime in?
2015-11-19 11:51:43
#3
from memory my knock sensor registers under 2v during a dyno run. ignition on should be 2.5v. check the ohmage, should be 550-560k.
2015-11-19 17:56:10
#4
I have solid aluminum as a motor mount. I think that mount might be contributing to false knock.

I have 2 other knock sensors that produce the same voltage .
Last edited by zurud on 2015-11-19 at 17-59-13.
2015-11-20 06:43:07
#5
Okay. If you get "knock" at say 1psi of boost, <11.xAFR, <20deg timing, then its looking a lot like a false positive.

Keep in mind that knock is hard to detect accurately, and often require lab grade equipment to get bang-on. Even with a cylinder pressure sensor, it can be tricky to get low/high knock limits dialed in. If you're feeling brave, and trust random strangers telling you what to do with your engine, I'd lower the voltage sensitivity %-setting in knock parameters section.

God I wish there was cheap cylinder pressure sensors available for the SR20 engine :/ I feel your pain on this one, I get "knock" on deceleration too, with prothane engine mounts...
2015-11-20 14:59:58
#6
Our knock sensor is rather useless with solid aluminum engine mounts. Your going to need some type of knock ear to properly tune the car.
2015-11-20 19:36:29
#7
I guess I have to remove my solid aluminium mounts and see.
I put them because I have several oem mounts that split open.
I am tired of it.
2015-11-21 03:06:55
#8
If the oem mount do not stop the knock I am going to uncheck both knock analysis and sensor.


I had been running like that for 3 years.
Only this year I found and check that option
2015-11-27 06:56:23
#9
Change to oem motor mount.
The results are the same .Still knock.

I am disabling knock analysis
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