Shemmer

I was recently left stranded on a busy down town street only to discover that my ignition coil primarys had developed a direct short across the + and - terminals which I believe subsequently took out the CD unit. I no longer have any positive voltage arriving at the coil but I have voltage on the red/white feed line to the CD module. The first thing I did to troubleshoot is disconnect the coil from the circuit and check for ignition voltage to the + side of the coil, then after confirming that there was no voltage present I removed the coil from the vehicle and applied voltage to the coil directly and it was then clear that there was a direct short across the terminals. If the CD module is in fact dead is it repairable or does anyone recommend a replacement that works well MDS possibly?
Is it normal that the coil could cause this damage to the CD or could it be something else?

nathanUK '81 930 G50

The MSD is a good upgrade. Do a search, IIRC the MSD 6AL is the one to use. Check it is the right model first.

Chuck Jones

My CDI died after I had the car for three months, and I replaced it with the MSD 6AL...which has the option for rev limiters also....and the car has been running great. You can also have your CDI box rebuilt by Zims....I think the link to your application is:

http://www.allzim.com/acatalog/Rebui...box_911SC.html

They charge $349 to rebuild it plus a pretty hefty core charge that's refundable. That's a heck of a lot cheaper than buying a new one!!. I've talked to several folks who have used the Zims rebuild and they're quite happy. You might also check Pelican.

Chuck

Shemmer

My original CDI has a "Repaired By Vertex" sticker on it but I don't see any option on their website for service to these units, they have the Permatune which not too many speak highly about.
Great and thanks for the link Chuck

Shemmer

Has anybody here repaired one? There must be a common part that goes in most cases. It should be directly related to the output voltage feed to the coil.