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Feedback System

  1. A single Red LED, located on the ECU, is used. Start engine and warm to operating temperature. Ensure idle speed and timing are adjusted to specification. Increase engine speed to about 2000 RPM for 2 minutes under no-load condition; enter self-diagnostic Mode II and monitor Red LED on ECU.
  2. Red LED should flash a minimum of 5 times every 10 seconds. If Red LED does not respond as described, check idle mixture (CO percentage level). See ON-VEHICLE ADJUSTMENTS article. If idle mixture adjustment does not affect LED operation, check fuel pressure regulator, airflow meter, injector(s), engine (coolant) temperature sensor or ECU.
ECU RED LED FEEDBACK RESPONSE

Application (1) Flashes (@ 2000 RPM)
300ZX 5
(1) Number of flashes in 10-second period.