I know, it's not detonation in a diesel engine. But that's about the most accurate way I can describe what's going on with my 85 300 wagon. If it were a gasoline engine, I would say the timing was way too advanced (pinging in a conventional piston engine). It starts perfectly, idles well, and gets about 24mpg all with 275k, but has been making much more than usual diesel clatter over the past month or so. Seems a bit worse when cold, better after running 10 minutes or so. When more throttle is applied, the clatter is worse. Part throttle or lift off, the clatter eases. Haven't used any injector cleaner recently but have in the past. Does my injection pump need adjusting? Other thoughts? Thanks in advance...

give it a couple of heavy doses of techron.If that does not help you have a mechanical problem

Check the following
 

Greetings,

I would check your timing chain to see if it is in fact worn beyond it's acceptable limits. Pretty simple procedure to check your timing alignment marks and while you have the valve cover off, adjust the valves as well. I would also take a look at your injection pump start of fuel delivery, could be that it is advanced beyond the 24-26 degree marks causing it to ping with to much advance.

Just a few thoughts

Charles

275k miles? Just how many miles do the injectors have on them? Bad spray patterns by the injectors can cause all kinds of noise. If there is any doubt about them, they can be tested for proper popping pressure and patterns on a test bench.

Good luck. Hope you find your problem quickly.

Injectors are relatively new....
 

But I suspect the pump timing also....

I have found on my 82 300D turbo that if I add a dose of cetane booster to each tankfull the noise is substantially reduced while running.

Rick