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  1. #1
    Join Date
    Mar 2008
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    Stamford, CT
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    Finallly Exorcised the Last Demon!

    Over the last several months I've been chasing several demons that have been robbing my 2006 SRT8 of performance.
    1. Purge valve and filter in the fuel tank. This was confirmed at the dealer and I'm in the queue for a new fuel tank
    2. Vacuum leak from hard lines. I replaced all the vacuum hard lines with new tubes.
    3. Refitted the vacuum line elbow to the PCV. The elbow had gotten hard, brittle, and cracked.
    4. Knock sensor on driver's side sending false positives. This was the least obvious to locate.


    Some of these took time to isolate and trace. The knock sensor was low on my list of possible demons, but ended up being significant. There's not much in these sensors, but somehow it had become hypersensitive and really killed my performance and gas mileage.

    Lesson learned, persistence...



  2. #2
    Join Date
    Sep 2006
    Location
    Calgary, Alberta
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    Accurate torque of the KNK sensor is very important...
    2005 Magnum RT---Viper Venom Red----440ci Aluminum block----Short Runner Valve Intake--410mm BAER 6S Monoblock Extreme--Eibach Multi-Pro 2

    Custom--Grille Work--Hood--Headlights--Side View Mirrors--Rear Spoiler--Rear Diffuser--SRV Control System--Turbine Wheels


  3. #3
    Join Date
    Jan 2008
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    Aurora, Ohio
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    How do yoy test a knk sensor and is the same on the 5.7?

    Sent from my SM-N950U using Tapatalk
    05' Magnum R/T HEMI Registry #889 CAI, JBA Ceramic shorties-CATless, MTCM, Predator , MDS, ESP, 3.06 Getrag swap, HALOS
    Aus liebe zum Automobile "Out of Love for the Automobile"

  4. #4
    Join Date
    Mar 2008
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    The KNK sensor is likely the same. Check RockAuto for your particular year.

    Because of the heat shield on the KNK sensors, they must be physically inspected, look for rust and other contaminants like oil. The KNK sensor that I found giving false positives was contaminated by oil. When reconnecting I made sure to torque the sensor properly and used dielectric grease around the outside of the connector to further protect the electrical contacts against contaminants like water and oil.

  5. #5
    Join Date
    Jun 2015
    Location
    Niagara Falls, NY USA
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    Quote Originally Posted by richierevs View Post
    The KNK sensor is likely the same. Check RockAuto for your particular year.

    Because of the heat shield on the KNK sensors, they must be physically inspected, look for rust and other contaminants like oil. The KNK sensor that I found giving false positives was contaminated by oil. When reconnecting I made sure to torque the sensor properly and used dielectric grease around the outside of the connector to further protect the electrical contacts against contaminants like water and oil.
    Could one of those false positives be phantom misfire codes? I've been chasing shadows.

  6. #6
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    Mar 2008
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    Stamford, CT
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    Quote Originally Posted by Blackjac 716 View Post
    Could one of those false positives be phantom misfire codes? I've been chasing shadows.
    Hard to tell without more info. If the KNK sensor starts acting weird it will show up on your wideband AFR (if you have one). I have two, one for each exhaust bank, which allowed me to trace the problem. When a KNK sensor becomes hypersensitive, the AFR will start to go rich at various times, even on cruise. In a way it's similar to a random misfire without any codes. The PCM gives the KNK sensors high priority and will retard the ignition timing as a way to protect the engine. As the timing is retarded the AFR goes rich, performance drops as well as gas mileage.
    Last edited by richierevs; 03-22-2020 at 10:24 PM.

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