Owner's Problem Description
The owner reported that their 1990 Honda Accord stalled while driving. The maintenance required light was flashing, and after pulling over, they were able to restart the vehicle after a few attempts. It operated normally for the rest of the day. In the previous month, they experienced occasional hesitations while driving but had no stalls until this incident. The owner took the car to Autozone, but no trouble codes were retrieved.
Professional Technical Analysis
This 1990 Honda Accord is equipped with a 2.2L inline-four engine and automatic transmission, with an estimated mileage of around 150,000 miles. The owner experienced an intermittent stall while driving, with the maintenance required light flashing. This symptom often suggests potential issues related to the ignition system or fuel delivery. In particular, the flashing maintenance light could indicate an underlying electrical fault or sensor issue. Given the history of hesitation over the past month, this could point to a failing ignition switch, which is a common failure in older Honda models. During the stall, it is critical to check if all dashboard indicator lights remained illuminated, as this could confirm if the ignition switch was indeed the culprit. The absence of trouble codes at Autozone suggests that the issue may be intermittent or not severe enough to trigger a fault code. The current vehicle condition is concerning as intermittent stalling can pose a safety hazard on the road. Components like the ignition switch, fuel pump, and electrical connections should be closely examined for wear and proper function. Based on my experience, ignition switches in vehicles of this age can fail due to internal corrosion or heat-related damage, especially if the vehicle experiences heat stress conditions. Given the situation, it is essential to conduct a thorough diagnostic to confirm the exact root cause before proceeding with repairs.
Possible Causes
Most common causes (ordered by frequency):
- Ignition Switch Failure: The ignition switch may be failing, which is a common issue in older Honda models. A faulty ignition switch can cause intermittent power loss to the engine, leading to stalling. This issue is especially prevalent when the switch is subjected to heat, which can cause internal components to fail. The switch should be tested for continuity and proper operation under load. Replacement part number for the ignition switch is OEM P/N 35130-SV4-003. - Flashing maintenance required light, intermittent stalling, potential loss of all dashboard lights during stall.
- Fuel Delivery Issues: If the fuel pump is failing or there is a clog in the fuel filter, it can result in insufficient fuel reaching the engine, causing stalling. The fuel pressure should be checked; it should be around 35-45 PSI at idle. If the pressure is low, the fuel pump may need to be replaced. Fuel pump part number is OEM P/N 17040-PY3-003. - Poor acceleration, hesitation before stalling, low fuel pressure readings.
- Electrical Connection Issues: Corrosion or loose connections in the ignition or fuel system wiring can lead to intermittent power losses, which could cause stalling. Inspect all related electrical connections for corrosion or looseness. Voltage drop tests should be performed to ensure proper voltage is being supplied during operation. - Fluctuating electrical performance, visible corrosion on connectors.
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 OBD-II Diagnosis: Begin with a thorough OBD-II system scan using a professional scanner or the GeekOBD APP to capture any stored codes, even if none were found previously. This ensures no underlying issues are overlooked. Live data monitoring will help assess engine parameters during operation. Check for voltage levels at the ignition switch during cranking.
- STEP 2 - Inspect Ignition Switch: With the vehicle running, test the ignition switch for proper operation. Check for continuity and voltage drop across the switch terminals when operating the key in various positions. A voltage drop greater than 0.5V may indicate a failing switch. Replacement should be done with OEM parts for reliability.
- STEP 3 - Fuel System Pressure Test: Conduct a fuel pressure test to ensure the fuel pump is delivering adequate pressure. Attach a fuel pressure gauge to the test port; it should read 35-45 PSI at idle. If readings are low, inspect the fuel pump and filter for clogs or damage. Replace as necessary.
- STEP 4 - Check Electrical Connections: Inspect all electrical connections related to the ignition and fuel systems. Look for any signs of corrosion or looseness. Perform voltage drop tests across connectors to ensure proper voltage delivery. Clean and secure any connections found to be problematic.
