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Datalog - Knock Sensor

26K views 57 replies 16 participants last post by  BlackBetty2012 
#1 ·
Hello, I recently installed a JLT CAI and Steeda Tune on my 2013 GT. The tune has only been on the car for about 30miles and i decided to log some data to ensure nothing looked too crazy. I noticed the knock sensors were giving readings, even at WOT, which concerned me. As you can see, this first recording shows knock sensor readings of -5deg to nearly 4deg. I recorded a few more WOT pulls after this and all values were between -4 to 0. I am unsure if this is normal/excessive or if this is possibly just due to the car learning the tune and i need to give it some more time.
 

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#2 ·
according to what Ive been learning lately, - actually means it is adding timing, and + means it is taking out timing, yeah odd I know
 
#6 ·
I believe redline is 7k.. i haven't taken it above 6500rpm at the moment. Being that the tune is still new to the car and the car needs to learn/adjust, I am probably OK knowing Steeda's reputation with a "safe" tune. I mostly wanted to determine if there is a dangerous level of knock that I should keep an eye out for (I have friends with turbo 4cyl who don't like anything above 5deg - that is a significantly different application though of course!). I plan to put a bit more mileage on it over the next few days and do some more recordings.

I have sent two data files to Steeda and will see what their thoughts are. Quick picture of my second recording. Looks like knock values stay between 0 and -4deg.. also looks as though the knock value reduces after doing a few pulls to around -2deg... Makes me think the car just needs to get educated a bit more before worrying :D
 

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#7 · (Edited)
did you even read my reply???? the - minus means timing is being added while the + positive means timing is being pulled therefore your log is showing timing being added, meaning the ECM saw no knock and added some timing for more power
 
#8 ·
Scott, not disagreeing with you or saying you're wrong. Is anyone else able to confirm this? It seems odd to me that the ecu would make adjustments because it doesn't sense knock, but maybe that's how it works..

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#11 ·
Never heard of that whatsoever. Your pcm is not going to add timing on its own. Every degree of timing is critical on these cars. So the pcm adding it automatically could be a disaster.

My knock sensors are completely turned off in my tune. And not once has it ever added timing automatically ?

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Not to mention does not make sense either. You have to add timing manually does not do it on its own.

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doesn't make sense to me either fellas, but research it, you'll find the same info I found. it's up to the tuner how much timing can be added if no knock is detected



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#9 ·
Never heard of that whatsoever. Your pcm is not going to add timing on its own. Every degree of timing is critical on these cars. So the pcm adding it automatically could be a disaster.

My knock sensors are completely turned off in my tune. And not once has it ever added timing automatically ?

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#30 ·
Have you clicked on the picture of the graph? the timing is showing a negative in front of it. That means the car is adding degrees of timing per a clean reading of the knock sensor. If the computer receives a clean signal from the Knock sensor it can be written in the tune to add a certain amount of timing. Mine is a Lund tune and it will add up to 2*. It usually does this under around town conditions but not at full throttle. You really should understand what you're talking about before you give advice to people.
 
#13 ·
I'm with Rapinator on this on.. adding timing "just because it can" doesn't make much sense to me. There wouldn't be a need to have specific tunes for specific octane levels if that were true. Still waiting on a reply from Steeda to see if this is normal. I tried to datalog the stock tune w/ stock intake, but unfortunately didn't realize that the x4 tuner only saves the most recent tune :banghead: . So I can't compare to that as a baseline.
 
#15 ·
I agree.. Still waiting on a reply from Steeda. I will try calling them after work. If they don't respond this afternoon, i may throw the stock intake and tune back on the car to get a baseline. Limited hassle and good information to have. I was just hoping someone else may have looked at or had similar recordings as this for comparison. Or that Steeda would comment on it :D
 
#17 ·
Still no word back from Steeda.. Another data log. Seems as though the knock is peak at WOT, which is never good. May leave the car at home until i can get some answers. Car seemed to drive better with stock intake and steeda 93 tune, but if this is all part of the car learning, I don't want to start all over :confused:
 

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#18 ·
So I decided to put the stock intake and tune back on the car and log some more data. I figured I'd post the results. Turns out the car knocks at WOT even with the stock intake and tune. Makes me feel slightly more confident that my car won't explode.:thumb:
 

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#20 ·
just why do you think the knock sensors are there? there are times when the fuel we use is not the best quality, or exreme heat, engine is heat soaked etc. it's silly to think stock tunes don't knock........

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#21 ·
A bit new to this.. Question 1: what is PID? Question 2: how do I find out?

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#23 ·
My other potential issue is this menu within the SCT Livelink program.. I just left everything as-is. Any suggestions on what to choose??

To further confuse - here's an article from another forum discussing what +/- values mean. :confused:

SCT Datalog "Knock Sensor" PID - Ford Mustang Forums

One of the comments says that the knock sensor measures crank degrees in the direction of rotation.. meaning a negative number would actually indicate advancing the timing and a positive number would mean retarding the timing..
 

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#24 ·
That is correct. When you see the -# it means the computer is advancing timing or adding degrees. A lot of us see this "Knock sensor activity" and first instinct is the car's detonating. You have to be concerned about the positive # as that means is positive for spark knock. Your data log screen shot only shows 1* at WOT. That's not to bad. Could be low quality fuel or false KR from exhaust noise.
 
#25 · (Edited)
I also said the minus is adding timing but was written off lol, it's how these cars make different power from 87 - 93 octane, the ecm doesn't magically know there is premium fuel in the tank or regular, and if people actually think the stock tune doesn't knock, well then why have the KS at all right?

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#26 ·
scott_O, i was certainly not writing you off! In fact, i was hoping that you were correct - since that would be a good thing for me! I think we all know that you can't trust everything that everyone says on forums!

Steeda recently contacted me and said that they are looking into it.. either way, I will continue to drive the sh*t out of the car!
 
#27 ·
yeah I understand man, alot of bad info out there for sure. as I said, the **** doesn't make sense to me either but I've done extensive research on it. as far as adding timing when knock isn't detected, it's how these cars make more power on different octane fuels to a certain extent, the tuner sets how much timing can be added when knock is not present

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#33 ·
He was telling you it's not going to randomly add timing because your knock sensors are disabled. So your car will not. If you think he's telling you something different than you are misunderstanding him. Either that or he's completely clueless. You have a data graph posted right here showing timing being added. Don't believe me, believe the proof right in front of your face.
 
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