A 1993 Subaru Impreza exhibited a no-start condition with unusual Check Engine Light (CEL) behavior. Initial symptoms included low voltage despite a new battery and alternator, and a “hollow” cranking sound indicative of a timing belt issue.
The timing belt was found to be one tooth off and was corrected. However, the no-start problem persisted. Upon turning the key, the CEL illuminated briefly but then extinguished. The vehicle would not enter diagnostic mode.
Further inspection focused on the electrical system. The ignition relay was replaced, and the fusible link connection was cleaned, but neither action resolved the issue. Connecting jumper cables to provide additional power resulted in a more consistent CEL illumination, although it still exhibited intermittent blinking.
With the added power, the engine eventually started. The cranking sound returned to normal before starting. However, subsequent attempts to start the engine resulted in the hollow cranking sound and no CEL illumination, suggesting the Engine Control Unit (ECU) was cutting fuel and spark.
After repeated attempts, the engine started again with a normal cranking sound and a flickering CEL. The car has started consistently since then. This intermittent behavior points to a potential ECU malfunction. A common ECU failure symptom is a complete lack of CEL illumination. However, this intermittent CEL behavior and no-start condition is less common. Replacing the ECU is a recommended next step in diagnosing this issue. Observing and documenting the CEL behavior through video recording can provide valuable diagnostic information.
