2004 Tahoe 5.3L Help

Discussion in 'The Garage' started by Pink_Vapor, Jun 23, 2019.

  1. Pink_Vapor

    Pink_Vapor Well-Known Member Supporting Member

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    I’m scratching my head, what’s my next step?
    It was parked for a couple years after cam bearing 3 spun and then the fuel went bad.
    I rebuilt the engine, new knock sensors and harness, cleaned K&N air filter, cleaned the MAF sensor, fuel filter (I couldn’t blow air through the replaced one it easily).
    The two confirmed codes are P0332 and P0327, bank 1 & 2 knock sensors. I had read the oil from a K&N filter can cause a film on the MAF sensor leaning the engine and causing knocks, I assume the filter would have the same effect. I suspect the injectors. I just ran a bottle of HEET and SeaFoam in 5 gallons of gas through it.
     
  2. THE PUNISHER

    THE PUNISHER Member

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    Did you replace the knock sensor wiring harnesses, they have know to go bad.
     
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  3. THE PUNISHER

    THE PUNISHER Member

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    Also need to look at a live data stream to see what the fuel trim is
     
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  4. Mike Overlay

    Mike Overlay Lacks seriousness Staff Member Benefactor Charter Life Member

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    And get pinched under the intake when installing.

    I have never seen an air filter of any style cause a lean condition setting knock sensor codes. That is not how that system works.
     
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  5. Burt Gummer

    Burt Gummer Abusive Staff Member Staff Member Benefactor Charter Life Member

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    This man is a 5.3 genius. Listen when he talks
     
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  6. Pink_Vapor

    Pink_Vapor Well-Known Member Supporting Member

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    I did, and made sure it wasn’t pinched/grounded by the intake.
    I pinched the first harness :confused:, made sure it didn’t happen a second time.
    I saw a warning about an oily film build up on the MAF sensor, especially if the filter’s heavily oiled.
     
  7. Pink_Vapor

    Pink_Vapor Well-Known Member Supporting Member

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    Fuel pressure is 50psi Key On Engine Off and when accelerating. 42psi at idle.
    At idle in park
    C7B5E020-53C9-4B2A-B66A-8BDFBFFF5C2C.jpeg

    Idle in park
    20F3EA66-B65B-464B-B544-F83B0FD12B7E.jpeg

    @ 2k rpm in park
    267E226B-E38F-4FC2-ACD7-6D6FBC87A575.jpeg
    CBF88B69-E9F5-467B-B88C-2289F89B25A7.jpeg
    6CA9FFF5-CA27-4D93-8DFF-6657573FFFB1.jpeg
    6C1E706F-4CDB-4408-9F39-9B52C6222F92.jpeg
    B1B34D07-412D-47FD-B07D-0E47800145A3.jpeg
    Any thoughts?
     
    Last edited: Jul 13, 2019
  8. THE PUNISHER

    THE PUNISHER Member

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    Does the upstream sensors (before cat) read high the low fast? .800-.100 should be switching fast. Ones behind cats (post) should be switching slower than the fronts.
     
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  9. Schattenreiter

    Schattenreiter Member

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    Have you got the two harnesses plugged to the right sensor. I know zero about the 5.3 but I once had a Fiat eng that came from the factory with the upstream and down stream noxs sensors plugged up backward. Upsteam harness was on down stream sensor and vice versa.
     
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  10. Mike Overlay

    Mike Overlay Lacks seriousness Staff Member Benefactor Charter Life Member

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    Where did the knock sensor and harness come from?

    That sytem is relatively simple. They measure a frequency that ripples thru the block when a knock occurs. The data screen shots you show are really of no help with a knock sensor issue.

    The knock sensor are used by the pcm to correct for spark knock, changing the ignition firing timing either by advancing or regarding the timing. You will not get knock sensor codes when lean or rich condition occurs.

    The codes p0327 and p0332 are when the knock sensor system has a fault. The fault is going to be either bad sensors, bad harness, damaged sensor harness or a break in the wiring from the harness connector on top of the manifold to the pcm.

    The lean condition that you suspect will cause p0171/p0174 codes to set. And since those codes are not present and the screen shots show the data parameters are normal, stop chasing that thought process.
     
    Last edited: Jul 13, 2019
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