Originally Posted by SdeBrandt (Post 11345708)

The car is a 1973.5 911T. I dropped the engine out for a refreshing, put everything back how I found it. Or at least I think so. Seems I’m not getting any voltage reading on the coil, of course no spark. The engine cranks over. Put in a new coil. Even bought another electric board, still nothing. Any suggestions? I’m about to pull the engine out again in case I missed something.

Originally Posted by timmy2 (Post 11346530)

You won’t see voltage at the coil on a CDI system.
Check your points are opening and closing properly.
Search “Dwell “.
Red wire plugged in Beside the CDI box?

Originally Posted by Walter_Middie (Post 11089013)

If Marion's 1974 911 is stock, he won't have the infamous "green wire". He should have a 3 pin CDI:

http://forums.pelicanparts.com/uploa...1604500198.jpg



You will not see any voltage at the coil like on a classic points and coil system, as the coil only gets a pulse from the CDI (shown in the AndrewCologne graphs above).

To get a spark to the spark plug in the engine:
First, you need power to the CDI.
Next you need to have a way to trigger the CDI

Then the CDI will send a pulse to the coil which will increase the voltage and send it through the high tension lead to the rotor and to the selected spark plug. You need to verify that each step in this chain is working. 



1) Verify that the CDI is getting power. Do you hear it whining? If so, you are getting power to it. 



2) Verify that the CDI is producing a spark. You can do this with a "telegraph" test. Take the high tension lead off of the center of the distributor and put a spark plug on it. Ground the threaded part of the spark plug. With your plug attached to the center lead, open the distributor, remove the rotor, place your key in the run position, and manually open and close the points. Each time you cycle, you should see a spark from the plug. If you do not, you may have a bad CDI.



3) Verify that the coil gets a signal when you crank. Replace the rotor and distributor cap. Leave the plug on the center high tension lead. Crank the engine. Do you see a spark? If so, you are getting spark to the distributor. If not, your point gap may be off or there is some other problem with the connections. 



4) Verify that the spark goes to the spark plug wires. Reattach the center lead to the distributor. Attach your spark plug to one of the leads going to the cylinder spark plugs and ground. Crank engine. If you see a spark you may have a timing problem. If no spark, you have a problem with your rotor or distributor cap or your wires are improperly seated.