Possible 1995 knock sensor issue

Discussion in 'Chevy Truck Forum' started by logankelly, Jan 9, 2018.

  1. logankelly

    logankelly New Member

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    My son switch out starter on his 1995 k1500 then took it for drive within a mile truck spit and sputtered all the way back now will not stay running. Found out wire has come off the knock sensor. Haven’t look at truck yet. Would the ECM detected the non-connection and put the timming that far off that it won’t run? If so what would be the solution? Haven’t look at truck since. Any ideas?
     
  2. greencamaro1981

    greencamaro1981 Full Member

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    it should run in limp mode with an unplugged knock sensor but, yes it will retard the timing until it gets a reading (obviously it wont get a signal) so it will just wander all over the place
     
    MikeG and gmctrucks like this.
  3. logankelly

    logankelly New Member

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    just by trying to start engine will it read sensor is plug in. Since it cant run should I do a manual timming on it such as finding TDC for #1 and make sure rotor is at #1 wire
     
  4. dirtrider73068

    dirtrider73068 Senior Moderator
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    No need to adjust the timeing leave it be for now.

    If it was unplugged it could have set a code, then like was said the ecm adjusted timing to compansate for it not reading it.

    I would plug the sensor back in if you have the OBD1 port unhook your battery for about 30 seconds to erase any codes in the ecm, some newer gm vehicles have that theft lock radio if you do make sure you have the code to unlock it. Then see if truck will start and run, if it does then your good go, no need to touch timing it didn't physically move, the computer did it in the programming by firing the spark at a different time in the combustion cycle.
     
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