I'm going bananas!!!
I have a '92 S 420 L (Australia --- known elsewhere as a 400 SEL). It's pinging it's head(s) off!
According to the owners book it should, and has done, run quite happily on regular (91 ron). Now I have to use Premium (95 ron) or even ultimate (98 ron). It still rattles even with these higher octane fuels but not quite so badly. I've had the fuel system flushed, replaced the filter, injectors out and cleaned, and the fault log downloaded -- no faults.
Seemed slightly better after I installed new Bosch F8DC4 plugs.
I may have to resort to going to a dealer unless someone out there has any ideas.
the picture on the epc shows it as being on the crankcase, bottom left (as you sit in the car) - and is 272 US dollars [:0]
if the knock sensor isnt responding, the ign system will keep advancing the ign timing - but if it gets no signal back it wont retard it when it pinks..
Linear Mode
