Sudden KR Whats going on?
Thread Starter
Teching In
Joined: Jun 2007
Posts: 48
Likes: 0
From: Irving, Texas
Sudden KR Whats going on? I have recently developed significant KR in the lower RPM ranges. It is more prevalent as you reduce engine speed towards idle and during low RPM’s. While accelerating or steady cruise everything seems fine.
I have not changed anything lately and have no idea of what is going on with this erratic behavior. Can someone take a look at my scan? I also will include my latest tune.
I have not changed anything lately and have no idea of what is going on with this erratic behavior. Can someone take a look at my scan? I also will include my latest tune.
I would raise the min MAP and RPM for KR. Are you getting your commanded timing when going WOT? Your burst knock tables seem to have low values and burst knock doesn't show up as KR. It will just remove timing. You might consider raising them.
Thread Starter
Teching In
Joined: Jun 2007
Posts: 48
Likes: 0
From: Irving, Texas
BLOWNBLUE ZO6
I have running with nearly this same tune for weeks / months and have not seen this before today.
WAHUSKER
I did not think that pipes, rattles or outside vibrations would be read by KR sensors. My understanding was that it takes certain frequences within the engine to set off KR readings. I'm not an expert by any means.
I have running with nearly this same tune for weeks / months and have not seen this before today.
WAHUSKER
I did not think that pipes, rattles or outside vibrations would be read by KR sensors. My understanding was that it takes certain frequences within the engine to set off KR readings. I'm not an expert by any means.
BLOWNBLUE ZO6
I have running with nearly this same tune for weeks / months and have not seen this before today.
WAHUSKER
I did not think that pipes, rattles or outside vibrations would be read by KR sensors. My understanding was that it takes certain frequences within the engine to set off KR readings. I'm not an expert by any means.
I have running with nearly this same tune for weeks / months and have not seen this before today.
WAHUSKER
I did not think that pipes, rattles or outside vibrations would be read by KR sensors. My understanding was that it takes certain frequences within the engine to set off KR readings. I'm not an expert by any means.
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I have running with nearly this same tune for weeks / months and have not seen this before today.
WAHUSKER
I did not think that pipes, rattles or outside vibrations would be read by KR sensors. My understanding was that it takes certain frequences within the engine to set off KR readings. I'm not an expert by any means.
I have running with nearly this same tune for weeks / months and have not seen this before today.
WAHUSKER
I did not think that pipes, rattles or outside vibrations would be read by KR sensors. My understanding was that it takes certain frequences within the engine to set off KR readings. I'm not an expert by any means.
Can you actually hear the knock? or is this just on your scanner, Could be something failing such as your knock sensor, will not throw codes untill dead. Also could it be carbon build up? we had a car in the shop one time for cam install, sat around for a couple of weeks. After the mechanic was done, started the car and it sounded just like a rod was knocking, yes it was that loud. We could not figured what the hell happened, the mech said that it might be carbon build up in the heads, I said no way, well he was right...
Can you actually hear the knock? or is this just on your scanner, Could be something failing such as your knock sensor, will not throw codes untill dead. Also could it be carbon build up? we had a car in the shop one time for cam install, sat around for a couple of weeks. After the mechanic was done, started the car and it sounded just like a rod was knocking, yes it was that loud. We could not figured what the hell happened, the mech said that it might be carbon build up in the heads, I said no way, well he was right...
That's a lot of knock a low speeds and idle...definitely think it's a mechanical issue, nothing with the tune. Although the suggestion about your decay rate sounds viable. Check the mechanical condition of your car.
Thread Starter
Teching In
Joined: Jun 2007
Posts: 48
Likes: 0
From: Irving, Texas
I cant really detect any noise in the engine. About three weeks ago immediately after an oil change, the engine during idle and off idle rpm's started making a sound and frequency very similar to lifter sticking. Similar but not exactly, sound was not a sharp tick but more of a wipe or revolving motion and would come and go. Drove to a local shop with lots of LS experience and they also could not pin the sound to a specific location. Intent was to drop off truck on the following Monday and let them dive into it but over the weekend the sound suddenly stopped as quick as it began.
Today I performed more scans. I reduced timing as much as 10* through the entire range and still recorded substantial KR. Most was below 2000 rpm's.
When under acceleration and in boost I see no KR.
Definitely something going on. I am still at a loss for what.
Today I performed more scans. I reduced timing as much as 10* through the entire range and still recorded substantial KR. Most was below 2000 rpm's.
When under acceleration and in boost I see no KR.
Definitely something going on. I am still at a loss for what.
I cant really detect any noise in the engine. About three weeks ago immediately after an oil change, the engine during idle and off idle rpm's started making a sound and frequency very similar to lifter sticking. Similar but not exactly, sound was not a sharp tick but more of a wipe or revolving motion and would come and go. Drove to a local shop with lots of LS experience and they also could not pin the sound to a specific location. Intent was to drop off truck on the following Monday and let them dive into it but over the weekend the sound suddenly stopped as quick as it began.
Today I performed more scans. I reduced timing as much as 10* through the entire range and still recorded substantial KR. Most was below 2000 rpm's.
When under acceleration and in boost I see no KR.
Definitely something going on. I am still at a loss for what.
Today I performed more scans. I reduced timing as much as 10* through the entire range and still recorded substantial KR. Most was below 2000 rpm's.
When under acceleration and in boost I see no KR.
Definitely something going on. I am still at a loss for what.
Thread Starter
Teching In
Joined: Jun 2007
Posts: 48
Likes: 0
From: Irving, Texas
Is it possible the sensors could pick up anything in the torque converter or transmission to cause KR ?
My heavy duty truck mechanics seem to think they hear some sort of rattle in the torque converter area after removing dust cover.
My heavy duty truck mechanics seem to think they hear some sort of rattle in the torque converter area after removing dust cover.
