OSSA ECU Exerciser
It is pretty straightforward to build an ECU exerciser. The 34-pin MX32A mating connector, manufactured by JAE (Japan Aviation Electronics), is available from Joe Scavone at Cycle Terminal. A mating connector for the Kokusan Denki communications interface is also available from Cycle Terminal. It is a 4-position Sumitomo HM090 series.
ECU exerciser on the bench
Simulating Sensors and Inputs
By far the most difficult part of the task is generating the flywheel pickup signal. An arbitrary waveform generator is required. These devices are sometimes called ARBs. I used an Agilent 33120A. More on this later.
Measured flywheel pickup waveform
Synthesized flywheel pickup waveform
Fuel injector pulse
ECU connector with numbered pins
Pin removal tool, insertion location
Correct pin orientation
CDI Output Special Consideration
CDI firing pulse
This is a placeholder for a discussion of the Easy-Start unit I repaired and reverse-engineered. It is an unusual, but clever design. The potting compound was very soft and sticky, yet crumbly. I accelerated the de-potting process with alcohol (figuring acetone would melt the plastic enclosure). There was also a conformal coating over the PCB. The PCB was well-marked with silkscreened component placements.
It uses a Microchip MCP1623 step-up regulator. A Microchip PIC16F1824 controls timing and sequencing.
Positive end of filter capacitor marked
Easy-Start wiring to PCB connections
Easy-Start PCB, transistors annotated