[SoCal Driver]

Mike, Sounds like you've eliminated quite a bit of the electrical. The basic test for the injection is to jump the DME relay completely out of the circuit and see if it starts. If not then it's off to "Fase Too" of the testing procedure. I'll conjecture that the DME relay is working OK as you have power to the injectors and the fuel pump runs when you crank it.

Check the plugs to the reference and speed sensors. Could be loose or corroded. If not use an ohm meter between the center pin and one of the outer pins on each sensor. Should be around 1K ohms. Note the other side pin is an isolated ground shield. It will should show as an open circuit.

The rear most sensor, the one closest to the fire wall will show about 2 volts between the 1k'd pins during cranking. This is the speed sensor. The front of the two is the reference sensor and should show a 2 volt pulse. Might be hard to pick up on a digital volt meter. You can see the needle jump on an older analog meter.

There is a way to use a diode to see the pulses too. The Bosch/Porsche DME Test Plan has a part number of 171 919 081B with a 1/4 watt 220 ohm resistor on the negative side of the diode. Think any diode will work. Connected across the two active pins on the sensor you should see the diode flicker. Or you could get an injector pulse checker from Pep Boys or Kragen or ???? and check to see if the injectors are firing as the reference sensor is responsible for firing both the injectors and the coil.

So basically it's down to the reference sensor, fuel pressure or loose/corroded solder joints in the brain to get spark and/or the injectors to fire.

Just because the fuel pump runs does not mean you have fuel pressure. There is the filter and dampener in the way of the injectors and going out of the fuel rail the pressure regulator.

There are other poor running considerations but we will save those for;

Fase 3 !