I'd also clean & test the crank position sensor. Pins 1&2 off the sensor should read about 640ohms. Pins 1&3 and 2&3 should have very high readings, at least 100Kohms. If you're using the Bentley manual for the M42 motor, it has the wrong specifications - 1280ohms for the cam sensor, 640 for the crank sensor.
We've found that the rust that tends to cover the sensor face at the crank pulley can shield the signal. Without a good crank sensor signal, the computer will never trigger the fuel pump.
Also, be sure you don't run a resistance or continuity test on the wiring harness/chassis side of the engine wiring. A multimeter can overload electronics like the computer or gauge cluster and permanently damage them.