Accord and Prelude models 1990-91
The Programmed Fuel Injection (PGM-FI) system is a fully electronic engine management system based on a microprocessor. The Electronic Control Unit (ECU) is responsible for:
- determination of fuel injection time and duration,
- air intake control,
- setting the ignition timing,
- enrichment of the mixture during cold start,
- fuel pump control,
- fuel supply cut-off,
- operation of the air conditioning compressor,
- generator control,
- operation of the EGR system,
- cleaning cycles.
The ECU receives electrical signals from a large number of sensors and sources located both on the engine itself and around it. The output signals from the ECU are determined by processing the incoming signals in accordance with programmed parameters. The ECU contains additional memory, backup and fail-safe functions, as well as diagnostic capabilities based on symptomatic diagnostics and storing error codes. For testing, it is always necessary to use diagnostic cards, as well as a Honda test harness, a voltmeter and an ohmmeter.