I am trying to revive a 1983 928S that has been idle since 2001. I put some fresh gasoline in the empty tank, installed a fresh battery and it cranks but it doesn't start. I checked for spark and there was none. How do I diagnose a no spark condition.
Thanks
Jorge

 

relays and fuses first, then the RPM sensor on the crank

 

I've got the same problem myself, right now. WSM starts with cleaning ground points. While it's most likely relays, fuses and RPM sensor (as per Lizard931), will get you a spark, don't overlook this maintenance item as well.

 

Defect in the ignition switch often causes problems of no spark too. Use a voltmeter on the coil wires. The + side should be about 11V, and the - side should pulse rapidy at crank RPM. You're going to need a voltmeter to test everything in the 928.

 

83 is analog, no RPM sensor.

Check the special wire from the distributor, over the engine to the spark box on the fender wall. It should be green, and the connectors in good shape. If it is black and stiff, and/or the connectors are crumbling, then it needs replacing.

 

As suggested, test the ignition relay. If it's not good, you can just remove the aluminium cover and squeez the contact together by hand. If the car starts, replace it with either another good used or a new one.

 

No ignition relay in '83. Unfused switched ignition.

 

Why does everyone jump into electronics first..... Is the distributer turning?

 

Thanks for the suggestions I will give them a try and let you know how it worked out.

 

Occam's razor.

 

Check for voltage at the coil resistors under the power steering reservoir.