Testing Automotive ECUs

I am using the logic analyzer today to look at the injector signals, ignition signals. The ignition signals show the distributor reference signals, and the drive signals for the coils. This is a waste-fire system, it has a quad terminal coil pack that has two coils each with two high voltage terminals. The tach output sums the ignition signals, so any standard tach may be used. The side benefit is, no tach loading on the coils for improved ignition.

The logic analyzer is small and inexpensive via the USB port on PC. The software easily measures time between signal edges. From the measured times, it is easy to calculate RPM, injector pulse widths, ignition dwell, and ignition timing in degrees.