1973/450sl trigger points
 

What are the sypthoms of trigger points that have gone bad. At what intervals are they cleaned or replaced? thanks

which trigger points?
 

Which points are you referring to? There's a set for ignition, as well as for the fuel injection system....

Prior to replacing the injection trigger points in my '73 350SLC the engine (3.5 M116 with D-Jetronic) would suffer intermittent misfire at low speeds, especially after a long journey at higher speeds. The misfire was injection related (use something long like a screwdriver as a stethoscope to listen to each injector) with pairs of injectors intermittently missing. Cleaning the trigger points would temporarily cure the problem. The permanent fix was a new set of trigger points (at great expense). That was years ago and I have not had cause to touch them since.

1973/450sl trigger points
 

I am referring to the trigger points in the lower distributor tray. Thanks for your responses.