sporatic knock
02-05-2007, 07:13 PM
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sporatic knock what causes sporatic knock ( 1 and 2 degrees) in various areas. I logged my knock retard and I am getting sporatic knock in various cells. Hp tuners
02-06-2007, 02:32 PM
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It can sometimes be caused by an abrupt change in timing values from cell to cell. Smooth is the key to timing changes. Generally, though, too much timing, or too lean. If you're not in PE mode, the PCM will correct fuelling to stoich, so you have too much timing. If you're WOT in PE mode, fuelling is locked, so it can be either too little fuel, or too much timing.
Then again, over-active knock sensors can cause the problem too.
Start from a stock binary, and set your PE table to what you want your afr to be. Then using a wideband, tune the VE table in open loop, tune the MAF table in open loop, restore closed loop and allow the STFTs to control day to day fuelling. Then fix any timing problems. My guess is that you won't have any.
Then again, over-active knock sensors can cause the problem too.
Start from a stock binary, and set your PE table to what you want your afr to be. Then using a wideband, tune the VE table in open loop, tune the MAF table in open loop, restore closed loop and allow the STFTs to control day to day fuelling. Then fix any timing problems. My guess is that you won't have any.