Diagnose an E36 no-start in a fixed order: fuel, then spark, then the immobiliser.
- Confirm the fuel pump primes (a brief buzz when the ignition goes on)
- Confirm spark
- Confirm the crank-sensor signal
Reading the result:
- Good fuel AND spark but no fire → look at timing and the crank signal
- Neither spark nor injector pulse while the starter cranks normally → suspect the EWS immobiliser (on a failed key handshake the DME shuts down both ignition and injection while the starter still turns)
To tell them apart: EWS kills spark and injector together; a crank-sensor fault does something similar but is heat-intermittent; a fuel-supply fault leaves spark present. EWS II arrived on the E36 around 1995, so earlier cars predate it.