78 SC Targa CDI Module Always On

[78_sc_targa]

Here is my story:

Car drove fine the last time I drove it.

Removed battery ground.

Took out the bracket on the left side of the engine compartment that holds the CDI, regulator, 3 fuse holder, relays, etc. The 3 fuse holder and some wires connecting to it were corroded. So I took the entire module out to clean and replace the 3 fuse holder.

I took the CDI off and opened it up (just curious to see what is inside). The 31/1 power ground pin was damaged (the lead was fragile and fell apart when touched). So I soldered the good parts of the lead together.

I put a new 3 fuse holder in and installed everything.

I connect the battery ground and the CDI module starts buzzing. Even without the ignition on. I confirmed there was 12VDC at terminals 15 and 31/1 at the CDI connection plug without the ignition on.

Any ideas what might be the problem here? Bad ignition switch?

Anything I can do to test this out?

Is there a ground strap connection on the back of the bracket that holds the CDI, regulator, etc?

[47silver]

did you have a problem with it not shutting off before you did the work?

If you did not then you connected the key on wire to a always on connection.

Looks like the B terminal on the cdi should be to the the top fuse on the 3 fuse holder,,and that should go to the front fuse block which should be on a key on terminal.

[78_sc_targa]

I turned the car on and it would not turn off. Took the key out and still the motor ran. Took the battery off and still it ran. The only way I turned off the motor is to remove the CDI connector.

I removed the new 3 terminal fuse holder and inspected it. It looks like the new fuse holder is different from the old one (even though I gave the Porsche parts guy the number off my old fuse block). From the front the fuse holder is exactly the same. When you turn it over all (3) terminals are shorted together on one side. On my old one only (2) of the terminals are shorted on one side.

I did a little research on my old terminal block ( ending in 02) and it looks like the one they gave me (ending in 05) is the superseded part. So I cut the 3 shorted terminals to make it only short the 2 terminals.

The CDI no longer is on all the time now. Only when the ignition switch is on does it turn on.

Thought I'd post my findings in case somebody else runs across this.

The car now turns on and off as expected. Although something still seems to be not right. Idle is okay but when giving a little gas at idle it seems to lag. Didn't have time to drive it. Will try it tomorrow. Maybe I damaged the CDI?

[78_sc_targa]

Is there a ground connection from the ground point behind the fuel filter to the bracket that the CDI sits on?

Hey 47silver, where I can I get the drawing you posted? Is there a book?