I believe pinging in a diesel is always related to late combustion, where too much fuel is injected before it has a chance to ignite, and then you end up with too much fuel igniting all at once. My EGR appears to be working correctly and my timing appeared correct as well last time I checked it. I wonder then if delaying the timing could be useful in compensating for wear & tear, but then again the engine seems to run too good to have much wear. Hardly any oil consumption either.

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2004 VW Jetta TDI (manual)

Past MB's: '96 E300D, '83 240D, '82 300D, '87 300D, '87 420SEL