Ignition Problem
 

I recently bought a 1972 911T. It doesn't run. The previous owner left it in his garage for the last 20 years. I'm having problems getting the starter to run with the ignition switch. I've performed many tests; however, the following two test are key.

1. Jumper terminal 30 and 50 on the starter solenoid. Results were as expected. The starter engaged and the motor turned over.
2. With the yellow wire removed from terminal 50, I engaged the ignition switch as if I was trying to start the car. At the same time, I measured the voltage between the lifted yellow wire and ground. I got ~12Vdc as would be expected.

It's almost as if their is too much resistance between the starter at terminal 50 and the ignition switch.

HELP!!!

I've heard of this.... there must be a thread here somewhere, might be the contacts in the key switch.

I had a similar issue with my head lights recently where I was reading 12V where I should have but the head light was not working. It turned out to be a corroded fuse. It was conductive enough that some thing was happening so I could read the 12V but it was not allowing any current through. I dont know if this is fuse protected but its worth a look. Check all your fuses, if you have the time pull them all and sand the tabs down to shiny copper. It would be worth your while to replace all the fuses any way, they are super cheap and you can get them at any local parts store.

Regards
Dave

Check your ground strap between the trans and the body and clean the connections. Also clean the ground at the battery. You can read 12 volts and have almost no current because of a bad ground due to corroded connections. As Dave says above "...and sand the tabs down to shiny copper" This goes particularly for the ground connections.

a good test light can sometimes give better info than a volt meter

a cheap test light might not draw enough if it is low watts