Transistorized wiring diagram

[MunichTaxi]

This diagram, copied from the MB workshop manual CD-Rom, show the wiring with the Transisitorized ignition. The diagram shows the #15 terminal of the coil connected to the Ballast resisitor, and the #1 terminal of the coil connected to earth.

When I purchased my 1970 280S, (March, 2004) the wiring was connected in this fashion. I was getting 12 to 12.5 mpg, the exhaust had a muffled sound, constant gas smell at tailpipe.

So I connected the #15 terminal to earth, and I connected the #1 terminal of the coil to the Ballast resisitor.
Gas mileage went up 5 mpg to 17mpg, the exhaust tone became resonant, clear and crisp, and no more gas smell was coming from the tailpipes.

See post "Coil Polarity Changed, Added 5 Mpg" (dated 8-18-04) for the beginning of this discussion.

[psfred]

There are two versions of the electronic ignition system, first one has the coil grounded directly, second version is grounded through the switchbox. I don't know which one is used on which original installations beyond the fact that all the V8s are the second version.

The coils are different, so if you have the wrong coil wiring for a specific coil, it won't work well....

Peter