Dme
 

For a 1985 911 Carerra 3.2, there is either no spark or no fuel reaching one cylinder. I'm wondering if it is possible for the DME to be doing this in either case? And is it possible to diagnose a DME to determine if the problem is the DME?

The DME fires all injectors together. The ignition events are identical for all 6 cylinders and the energy is routed by the distributor.

No Spark.
 

Have a look at the disributor/rotor/wires, and all conections.

Good luck,

Gerry

always carry a spare I say...

Check the OHMs on the ref/speed sensor

You might consider swapping the plug wire, maybe plug too. Ohm out the injector to make sure it isn't open, or check/swap it to make sure it isn't clogged.

And like Gerry suggests, checking the connections. Check the large bundle of injector returns (ground wires) which are tied to the same point on the intake. Look inside of the distributor. It wouldn't be your DME if the other 5 are working.

To answer your question, it can be diagnosed. With a strong magnifying glass check the solder joints for cracks and if cracked re-flow.

You do this at your own risk.

Doesn't sound like the dme RELAY as differentiated from the dme which would be the box under the left seat. I would continue the trouble shooting procedures as above.