Owner's Problem Description
The owner reports that their 1991 Honda CRX won't start after washing the engine. The vehicle was running perfectly before the wash. After the wash, the owner attempted to start the car but it failed to crank. Initial checks suggested possible issues with the distributor or timing belt, and the check engine light is illuminated. The owner has already dried the distributor cap but the problem persists.
Professional Technical Analysis
This 1991 Honda CRX with an estimated mileage of around 150,000 miles is experiencing a no-start condition following exposure to water during an engine wash. The primary symptoms include no cranking noise and the illumination of the check engine light. Initial diagnostics should focus on the ignition system, particularly the distributor and timing belt integrity. Given that the vehicle was operational prior to the wash, it's essential to investigate potential water ingress into the ignition components. The distributor's black/yellow wire should be checked for voltage when the ignition is turned on. If power is present, the distributor may be faulty. Conversely, if there is no power, the issue may lie upstream at the ignition switch. Additionally, if the distributor rotor is not turning during cranking, this may indicate a timing belt failure. The timing belt on these vehicles tends to degrade over time, leading to snapping or losing teeth, particularly if it was already worn. A thorough inspection of the timing belt is warranted if the rotor is stationary while cranking. The check engine light is significant and should prompt a scan for fault codes to identify any related issues. Currently, the vehicle condition poses a safety concern as it is inoperable, which may affect the owner's mobility. Observations of previous repairs or maintenance, especially regarding the ignition system and timing belt changes, will assist in diagnosing the root cause efficiently.
Possible Causes
Most common causes (ordered by frequency):
- Distributor Failure: The distributor may have sustained water damage during the wash, leading to poor electrical contact or shorting. If the black/yellow wire does not show voltage when the ignition is turned on, this indicates a problem in the ignition circuit. If water is present in the distributor cap, it can hinder the rotor's ability to deliver spark effectively. - Check engine light illuminated, no voltage on black/yellow wire, possible water presence in distributor cap.
- Timing Belt Failure: If the timing belt has snapped or lost teeth, the distributor rotor will not turn when the engine is cranked. This is a common failure mode in older vehicles, particularly if the belt has not been replaced as per maintenance intervals (typically every 60,000 miles). - No rotor movement during cranking, audible noise from the engine indicating potential timing belt failure.
- Ignition Switch Failure: A malfunctioning ignition switch may fail to provide power to the distributor. If the ignition switch is faulty, it may not send the necessary voltage to the ignition components, rendering the vehicle inoperable. - No voltage detected at the distributor black/yellow wire, symptoms not consistent with normal ignition operation.
Diagnostic Steps
Professional Diagnosis Process
Follow these systematic steps to accurately diagnose the issue. Each step builds on the previous one to ensure accurate diagnosis.
- STEP 1 - Initial Voltage Check: Begin by checking the voltage at the distributor's black/yellow wire using a multimeter. With the ignition switch in the 'ON' position, you should see battery voltage (approximately 12V). If there is no voltage, investigate the ignition switch and associated wiring for faults.
- STEP 2 - Distributor Inspection: Remove the distributor cap and check for any water accumulation or corrosion. Ensure that the rotor is securely attached and rotates freely. If water is present, dry the components thoroughly before reassembling and attempting to start the engine again.
- STEP 3 - Timing Belt Inspection: If the rotor is not turning while cranking the engine, remove the timing belt cover to inspect the timing belt condition. Check for any visible signs of wear, such as missing teeth or fraying. If the belt is damaged, it will need to be replaced immediately.
- STEP 4 - Error Code Retrieval: Use a professional OBD-II scanner or GeekOBD APP to retrieve any fault codes from the PCM. This can provide insights into any additional issues that may have arisen due to the wash or related engine components.
