Need advice for knock issue

Discussion in 'All Topics, Chips, and Tech for Buicks' started by Dan S, Aug 15, 2019.

  1. Dan S

    Dan S New Member

    I’ve had the GN for quite a while, and am looking to get it running right with zero to little knock. Car has a Walbro fuel pump hotwired, 42lb injectors with a 5.7 TT chip, stock MAF, stock turbo/intercooler, 160 degree thermostat, TPS is .42 at idle, fuel pressure is 40psi at idle, BLM is 128, boost gauge shows 16-17 at WOT, scanmaster 2.1

    At WOT O2 is 769 at 44mph and knock reads 4.5 at 31mph

    I was looking to get the O2’s closer to 800 so I added 5% fuel and set the BLM to 134
    At WOT O2 is 792 at 33mph and knock reads 8.7 at 33mph

    I thought adding more fuel would make the knock decrease? I didn’t check the AF at WOT nor did I check TPS at WOT. Should I continue to add fuel? Lower the boost? Any advice is much appreciated!
  2. EricM

    EricM Administrator Staff Member

    Knock can be from being too lean, or not enough octane for the given boost level, or it could be noise (not real knock). 33mph is about where the 1-2 shift occurs and sometimes there is noise there.

    You can try turning the boost down to see if it goes away.
  3. Dan S

    Dan S New Member

    Ok I will try lowering the boost a pound or two. Should mess with adding/decreasing fuel through the chip?

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