Need CDS help
 

I'm restoring a 72 911t and the engine hasn't run for 6 mos. Tried to fire it up and no spark. Went to the manual which said the CDS unit (perma tune) should have a whistling noise. There is 12V at terminal B but no whistling noise and only an occasional spark. Can something like this haapen from just sitting? Any trouble shooting tips? Thanks

The permatune does not whistle, but the bosch does. I have one of each, both in good working condition. If you would like to swap one into your car to see if that fixes the problem, I'll lend you one for debug purposes.

cdi blues
 

The power supply to the cdi unit, if three prong plug is the
center red wire which is energised from a fuse in the front
trunk fuse box.

Mygatts57,

If you go to www.permatune.com, detailed troubleshooting and testing instructions are there. They will bench-test the unit for you for $20 and tell you if it can be rebuilt. Mine couldn't be rebuilt and I had to buy a new unit (PP has them). Lonnie Lenarduzzi from PermaTune was VERY helpful and this was the very first project I did on my '74 last summer and all you need is a $100 multimeter. I also replaced the Bosch coil, distributor cap, plugs, wiring harness, etc... and the PermaTune unit hasn't cause me a problem since I replaced it. Good luck!