Volvo: Pre-ignition, knock sensor, pump fuel

Question
It is a 1987 240, done just over 200 000kms.  I have had to back off the timing so far to stop the pinging that I have lost a lot of power and the problem seems to be progressing. Could it be that that the Fuel pressure is falling off and it needs a new pump? Fuel injected of course.

Regards

Geoff

Answer
In a 240 that new, you have a knock sensor which should adjust the timing to enough extent that you don't need to retard it to avoid knock.  If you're finding you do, that sensor might have died (which is common).  I would replace it and see if the knock disappears.  Good luck!