Question to the CDI(6 Pin) Gurus!
 

Hello Everyone! SmileWavy

Got a used CDI. Was told that it worked. I never tried to run it yet. But was curious what was on the inside. :D

Took the cover off, and one wire/strap fell apart in front of my eyes... 31/1
Looks like it was burnt, or something...

http://forums.pelicanparts.com/uploa...1276019642.jpg


http://forums.pelicanparts.com/uploa...1276019712.jpg


http://forums.pelicanparts.com/uploa...1276019753.jpg


Would a simple replacement of the wire fix this whole thing?

Thank you very much!!!
Gene

The 31/1 is the ground. Something shorted like one of the diodes possibly. Do a search on Warren Hall. Warren posted a great thread on the CDI's years ago and will provide you with lots of information. There are some other good posts on CDI's here with Pelican.

Contact this company. I've heard they are the experts on rebuilding these CDI boxes:

Systems Consulting...Automotive Electronics

Marc

Thanks a lot guys!!! :)

Here are a few classics with great information.

http://forums.pelicanparts.com/porsche-911-technical-forum/226517-history-bosch-cdi-toubleshooting-info-parts-list-changes-schematics.html

http://forums.pelicanparts.com/porsche-911-technical-forum/203100-6-pin-sc-turbo-cdi-unit-repair-documentation.html?highlight=cdi+documentation

FYI - that was my dead CDI that lived for the documentation. Warren was such a great member of this board.

Now I remember where I have seen that name! At the top of the forum!!!

Too bad Warren is no longer with us! He will be missed!!!

These Bosch CDI units can be rebuilt. Pelican Parts (our host) amongst others are offering this service.

The internals are a DC/DC converter, a trigger circuit and a SCR switch. The DC/DC generator charges the internal main capacitor to around 400V-450V. The trigger circuit evaluates the VR (variable reluctance) signal from the distributor and generates a sharp spike-shaped signal for the SCR. It is a pulse-shaping stage. On the 6 pin it also generates the tach signal.

The SCR switches that charged capacitor to the ignition coil which acts as a transformer. It transforms the voltage by a factor of x1000 to 40,000V. A spark is generated and the SCR disconnects the coil from the capacitor. Then the cycle starts again.

That is in essence how the CDI (capacitive discharge ignition) works. As others said there is a lot of good information out on the board. Warren posted several Bosch manuals and circuit diagrams. Unfortunately, some have mistakes but overall it is pretty well documented.

Ingo

My bet would be that the 31/1 printed circuit connection was faulty, poor soldering, and the resulting heat buildup melted the connection.

Replace the connection and be done with it.

wwest I like your style!!! :D

If I do, and it doesn't fix the problem. The rest of the car's components will be fine?

Thanks! :)