Hi,
l have a 1983 Porsche 944 NA, l am getting no spark.
It was running fine untill it sat in the carport for 10 years.
l have replaced the DME relay and the DME module.
l have power at the coil, coil has been tested to be working. l am getting no power out of the middle of the coil/switching power at the terminals.
l am looking at the speed and reference sensors but whilst l am cranking the motor, l can not hear the fuel pump running which makes me think it is not only the speed or reference sensors l should be looking at. l have bridged the terminals at the DME relay and the fuel pump works fine.
Do faulty sensors cause the fuel pump to not switch on?
l dont have an oscilloscope to check the reference/speed sensor outputs. l have checked the resistances and they are in spec. Tacho does not bounce during cranking. l have just ordered new speed and reference sensors which should be coming in a week or so. Any common problems l need to look at?

Check all the ecu grounds & look for broken wires. If the fuel pump runs when u jump the relay that half of the circuit is good. The ecu or ignition switch supplies the power/ground to the magnet side of the relay to flip the hi current side on.

The coil should get power all the time on one side & switched ground from the ecu on the other. It should flash a test light cranking. l think its a grounding issue, corroded or broken wires. Mice like to chew on sitting cars.

Tach not bouncing = speed reference sensors. Those are your problem.