Originally Posted by
Chas
It depends.
I have seen a friend's Rover SD1 popping from the exhaust alot in addition to backfiring via the carb which was suspected initially down to worn valve springs. It was the camshaft in the end.
OTOH (it was a diesel mind you) my old PD Passat misfired terribly upon throttle. I have to this day not seen an intact camshaft quite so worn.
None of that is detonation though mate, it sounds like valves opening/closing at the wrong time in relation to the spark event.
The diesel is not comparable as it doesn't have a spark in the first place and essentially detonates all the time.
Originally Posted by
Marino
good morning,
at the beginning i also thought it was an issue of ECU that does not retard the timing but I tried 2 different ignition ECU (one without knock sensor) but nothing has changed. also i have tried to change the act sensor, metering unit, fuel ECU and fuel pump but nothing
.
i have already spent more than $ 500 in spare parts and equipment to control the AFR and timing. the only things that i have not changed are the dizzy and the camshaft.
What pistons do you have? What fuel are you using?
Unless somehow the cam has worn in such a way it has increased your dynamic CR, but I don't know if that's even possible?! lol