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Knock sensor - installed incorrectly from factory. Is yours?


Deer Killer

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It's supposed to be installed with a 60 degree angle from the rear, this is so that the housing and wire does not contact anything. Except on my car clearly it was just torqued down until the sensors housing bumped into one of the block re-enforcing ribs. This is not good for a highly calibrated piezo microphone.. Also it was torqued by a gorilla, clearly not the 17.8 ft-lbs specified.

 

Did it make a difference? Unofficial results, seems a lot less noisy, where I had confirm noise before. 1-2 hard shift got through with 0 FBKC at least once so far. That was damn near impossible before. I actually made a 30 minute drive to work this morning with absolutely 0 FBKC for the whole drive, also something I have never seen before.. Particularly noisy section at 2500 rpm ~1-2.0 loads is much quieter now.

 

If you're going to ask, yes it still detects actual knock.

 

I suppose possible further improvement by ensuring the wire does not contact the block in any way until the suspended harness connector, wish I had verified this while I was in there - that seems to be what the engineers were trying to get.

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knock-right.JPG.3e78cdf5915b0564e53bc1de76636e93.JPG

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knock sensors, specifically knock sensor CEL's are frequently the result of really bad gas. FYI.

 

 

secondly, I'm sure it wasn't torqued by a gorilla. Since 2005, the block has sustained hot and cold temps, the bolt is not suppose to come off with anywhere near the tightening torque rating.

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Just replaced one on my race car. For some reason, it seems as though they get a crack on the side. Either from over tightening on install or just normal heat and cold cycles on the car. The one I replaced did have a crack. It appeared to be the original, and lasted 150k miles. Make sure you clean the crud that likes to get in that area so it doesn't get caught under the sensor when you re-install a new one.
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knock sensors, specifically knock sensor CEL's are frequently the result of really bad gas. FYI.

 

 

secondly, I'm sure it wasn't torqued by a gorilla. Since 2005, the block has sustained hot and cold temps, the bolt is not suppose to come off with anywhere near the tightening torque rating.

 

I highly doubt it. I did have a knock sensor circuit low code thrown, after I washed down the engine with engine cleaner and water. However, the problem is that the knock sensor only has one pin in the connector, ground is taken _from the block_, of course dissimilar metals contacting over timing with salt and other crap all over the place and the connection suffers.. low = open circuit.

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*updates* a few days later, and it's confirmed it's _definitely_ quieter. Now I can tune timing with confidence for the first time, before it was always second guessing the knock sensor

 

I also did this mod which may be helping: The clutch line taps on the pitch stop mount, and it seems to make a clang, so I zip tied it loosely out of the way. Look at the rusty spot where it's been making contact.

photo-clutchknock.JPG.1d9e435f0567f36722aa23a440529941.JPG

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I also did this mod which may be helping: The clutch line taps on the pitch stop mount, and it seems to make a clang, so I zip tied it loosely out of the way. Look at the rusty spot where it's been making contact.

 

Wow.... that is very interesting. Wonder if that contributes to the infamous "shift-knock" issue.

My '05 LGT

My '07 Supercharged Shelby

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Subscribed.

5EAT here and like Deer Killer I am seeing knock in the same area, but FLKC not FBKC.

I've had IAM drop all the way down to 0.0 and come back up, I've had neg correction regardless of throttle input, etc.

17-18lbft, isn't that pretty much hand-tight?

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