Replaced knock sensors still problems

Discussion in 'Engine Performance + Maintenance' started by The_Viking, Aug 7, 2019.

Car Parts
  1. The_Viking

    The_Viking Newbie

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    2000 K2500 7.4
    It was falling on its face. Scan tool identified knock sensors were bad. Replaced both. Now in Overdrive under acceleration it’s doing the same thing it was doing prior repair. It’s only in Overdrive at about 1500 rpms it’s not as bad as it was but it’s still there, the sputtering, bucking. What else should I check? Fuel pressure is good at rails new cap rotor wires. I’m fucking lost.
     
  2. evilunclegrimace

    evilunclegrimace Does not always play well with others

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    Did you torque the knock sensors to the proper spec? If they are over tightened the can send a false knock signal to the computer.
     
  3. Schurkey

    Schurkey I'm Awesome

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    HOW does a scan tool "identify knock sensors as "bad""?

    Not possible as far as I know. To the scan tool, failed wire harness looks just like a failed sensor.
     
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  4. DerekTheGreat

    DerekTheGreat I'm Awesome

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    LoL reminds of my first ever experience with my MT2500 on our former '88 C3500. Some code regarding the speed sensor on the trans. I fired the parts cannon and bought a brand new one. Stabbed it in, no change. Code had further details which stated issue could be sensor or circuit. Checked circuit and sure enough, contacts on fuse were corroded. Would have been a zero dollar fix.
     
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  5. The_Viking

    The_Viking Newbie

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    I misspoke. Yes bad sensor. Changed both and it’s better but still sputtering in OD. This thing is killing me and I’m only a half shitty mechanic. Knock sensors torqued to spec
     

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