I run the car on 87 octane fuel. Always have. Apparently that isn't the best practice, but this isn't about that.I'll be happy to take reprimands and criticism as soon as I remedy this problem.

At the moment, the tank is nearly full of regular fuel - I think 87 Octane. The car recently started pinging a little bit under load, and now it pings incessantly and much more loudly whenever I get on the gas.

As far as I can tell, there are four things that might be going on.
1) Buildup/hotspots in the block/head.
2) Timing is off.
3) Knock Sensor out of commission.
4) Just an unlucky bad tank of gas.

Can someone please clue me in as to what kind of problem this might be? It started out of nowhere and I didn't change the octane rating of fuel whatsoever, and hadn't even opened the hood lately.

Any input would be greatly appreciated. Thanks in advance.

BTW. I plan to fill up with premium from a name brand station next time just to see if it will help, but I've got a couple of weeks' worth of gas in the tank and don't want to let this problem sit if I don't have to.

 

I doubt it is a timing problem since your EZ-116K system uses a crank position sensor (timing can't be adjusted). I would inspect/replace the spark plugs and check for OBD codes in both sockets 2 and 6.

See this for the cooling system info:
http://www.brickboard.com/FAQ/700-900/Cooling.htm

Cars used the 92 deg. thermostat unless it was a turbo, then it was 87 deg.

I would seriously consider flushing your cooling system at the same time.

If you plan on having the car for awhile and want to do the majority of the work yourself I would suggest the "volvo 240 service manual" from Bentley Publishers .... I got mine used for cheap off ebay. 200% better than Haynes or Chilton.

 

Thanks so much. I'll try and snag one of those manuals when I get a chance. Just spent the evening cleaning out my flame trap. ugh. need to buy a new one asap - seems like this one was probably original...