Knock Sensor ?
Thread Starter
Safety Car
Joined: Nov 2007
Posts: 4,446
Likes: 878
From: Bay Area CA
Knock Sensor ?
I read that the LS3 Knock Sensors can be over sensitve. After X amount of K.S. triggers, does the ECM revert to 89 octance tune to prevent further triggering? Does the ECM return to 91 octane after you fill up at the gas station?
What can be done to reduce the over sensitive Knock Sensors?
What can be done to reduce the over sensitive Knock Sensors?
Last edited by Mike's LS3; Jun 6, 2010 at 01:32 PM.
Former Vendor
Joined: Jun 2009
Posts: 603
Likes: 0
From: Tampa FL
Yes the LS3 knock sensors are sensitive. If the computer sees Knock it will revert to the Low Octane table, it will stay there for a certian amount of time with our seeing Knock before it moves back to the High Octane table.
You can desensitize the knock sensors through the tune, but i would only recommand doing that if you know that the Knock is false and not real.
Ian
You can desensitize the knock sensors through the tune, but i would only recommand doing that if you know that the Knock is false and not real.
Ian
Drifting
Joined: Dec 2009
Posts: 1,404
Likes: 7
From: Malverne New York
Yes the LS3 knock sensors are sensitive. If the computer sees Knock it will revert to the Low Octane table, it will stay there for a certian amount of time with our seeing Knock before it moves back to the High Octane table.
You can desensitize the knock sensors through the tune, but i would only recommand doing that if you know that the Knock is false and not real.
Ian
You can desensitize the knock sensors through the tune, but i would only recommand doing that if you know that the Knock is false and not real.
Ian
Thread Starter
Safety Car
Joined: Nov 2007
Posts: 4,446
Likes: 878
From: Bay Area CA
Thanks guys for your responses. I use only tier 1 gas, Chevroon 91 octane. Infineon raceway is nearby, which has unleaded race gas. I will try some and see what happens.
No codes are flashing, but I need to have a look at my oem tune to determine if I am getting any burst knock, false knock or real knock.
No codes are flashing, but I need to have a look at my oem tune to determine if I am getting any burst knock, false knock or real knock.
Thread Starter
Safety Car
Joined: Nov 2007
Posts: 4,446
Likes: 878
From: Bay Area CA
Racer
Joined: Mar 2006
Posts: 281
Likes: 4
From: Houston TX
You will get false knock if you get wheelspin as well.
I tuned a LS3 the other day on the dyno and was getting 1-2 counts of knock on a bolt on car with 24* of timing. After 2 pulls, I had dropped the timing down to 21* and I was still getting some. While I was driving the car up to speed I noticed that the muffler in the rear was rattling loudly against the frame. Then I found out that each knock event was tied to the rattle of the muffler.
I looked at his exhaust and the x-pipe was welded to the muffler. Whenever I see this on cars, it always brakes exhaust hangers because it doesn't allow the exhaust to flex when the engine torques over so it's not a good idea.
I turned down the knock sensors slightly and it fixed the problem.
I tuned a LS3 the other day on the dyno and was getting 1-2 counts of knock on a bolt on car with 24* of timing. After 2 pulls, I had dropped the timing down to 21* and I was still getting some. While I was driving the car up to speed I noticed that the muffler in the rear was rattling loudly against the frame. Then I found out that each knock event was tied to the rattle of the muffler.
I looked at his exhaust and the x-pipe was welded to the muffler. Whenever I see this on cars, it always brakes exhaust hangers because it doesn't allow the exhaust to flex when the engine torques over so it's not a good idea.
I turned down the knock sensors slightly and it fixed the problem.
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Thread Starter
Safety Car
Joined: Nov 2007
Posts: 4,446
Likes: 878
From: Bay Area CA
If the knock sensor, false or real, are triggered, will it throw a code. What can I use to determine that K.S. have triggered. I have a Actron code reader, will it show up on there?
If not, would I have to buy a tuners program, like HP, to read the file on the ECM?
If not, would I have to buy a tuners program, like HP, to read the file on the ECM?
