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Knock sensor

Discussion in 'GM Powertrain' started by 91Chuck, May 3, 2009.

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  1. 91Chuck

    91Chuck New Member

    I just purchased a 1991 K1500 4x.... the previous owner rebuilt the 5.7, and add a mild cam along with an eldelbrock intake. Small problem, the cel is on, and the code is for the Knock sensor. If I am correct, teh bigger than stock cam has set the code....is there a way around this. Long time sence I played with a Chevy. Anty and all help is apperciated!
  2. Jimmiee

    Jimmiee New Member 1000 Posts 100 Posts

    The knock sensor code sets when your computer hears a knock and it can't shut it up by retarding your timing. So a cam could indirectly cause a knock sensor code, as could any noise like a tappet, exhaust leak, fan belt, etc. Can you hear any engine pinging? Sometimes you can't hear the knock. Have you tried boosting your octane?
  3. 91Chuck

    91Chuck New Member

    I,m running 93 octane. No noises at all.
  4. Jimmiee

    Jimmiee New Member 1000 Posts 100 Posts

    The next step is test the sensor. A scanner showing the signal from the sensor to the computer makes this an easy task. Watching the scanner, tap on the exhaust manifold with a wrench and see if the signal changes. This will test for a bad sensor.
  5. 91Chuck

    91Chuck New Member

    Ok, I can get a scanner tommrow.

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