Using the diagram you reference:

pins 1-3 are connected internally - .1 to .3 is OK
pins 1-4 measure the internal capacitor thru the transformer and should not measure
any resistance, if they do (2250 ohms) it indicates a shorted capacitor.
pins 2-5 that's the tach output to the power input - of little value
pins 1-5 is the power input to the internal ground.

You need to measure pins 3-6 of the CDI harness and not the CDI unit to check
for a distributor signal (600 ohms, .5 - 1.0 volts A/C while cranking)

Again, if you measure resistance between pins 1-4 and/or by reversing the leads,
you've found the problem - a shorted internal capacitor, which typically happens
when there's a weak capacitor and the key is left on.

I haven't had time to measure the harness but I'll do that tonight.

I think I'm going to send my unit to Ingo in Santa Barbara. That seems like the best/quickest solution. I was going to buy a used "good running" unit but who knows if I end up with a marginal or bad unit that way.

Pelican Parts Catalog:


Bosch CDI Repair Service ** CUSTOMER MUST SEND THEIR CDI UNIT IN FOR REPAIR ** (includes 1 year warranty) [More Info] 911, 911S, Carrera and 911SC (1974-89)
930 Turbo (1976-77, 1986-89)

AT-CDIREPAIR
Bosch CD Ignition Units
[view in catalog] $200.00

I got my CDI back from repair. Car started right up!