December 16, 2023

Acura Legend (1990-1995) Running Rough? Engine Light?

Acura Legend check engine light, stalling, runs rough If your car is stalling, has the check engine light on, or running rough, this may be one of the common issues with this generation of the Acura Legend.  I’ve had my fair share of problems, but this is too common, especially the 1990-1995 models.  The problem is likely related to the Exhaust Gas Recirculation (EGR) valve. I’ll share my experience on how to troubleshoot and replace the EGR valve in these models.

Check for Recalls

Symptoms

A rough running car or an engine light are hard to ignore, but getting stuck due to stalling is the worst!

First, let’s look at the symptoms of a faulty EGR valve:

  1. Check Engine Light: Often the first sign something is wrong.
  2. OBD Codes P0401 and P1491: Codes specifically indicating issues with the EGR system.
  3. Rough Idle: The engine might feel uneven or shaky when idling.
  4. Reduced Fuel Economy: Your car’s mileage is worse.
  5. Engine Vibrations: These can be felt even when the car is not moving.
  6. Hesitation or Stalling: The car might hesitate when accelerating or stall unexpectedly.
  7. Long Cranking Before Engine Starts: It takes longer than usual for the engine to start.
  8. Failure of State or Federal Smog Tests: Can lead to increased emissions, causing smog test failures.

See all the OBD codes here.

Troubleshoot and Repair your Acura Legend

  1. Check the Check Engine Light: Use an OBD-II scanner to read the trouble codes. Codes like P0401 (EGR Flow Insufficient) and P1491 (EGR Valve Lift Insufficient Detected) are telltale signs.
  2. Visual Inspection: Visually inspect the EGR valve for any signs of damage or excessive carbon buildup.
  3. Check the Vacuum Line: Ensure that the vacuum line connected to the EGR valve is not cracked or loose.
  4. Test the EGR Valve: Apply vacuum to the valve with a hand-held vacuum pump. If the engine idle does not change, the EGR valve might be faulty.
  5. Check for Other Codes: Other related OBD codes include P0400 (EGR Flow Malfunction), P0402 (EGR Flow Excessive Detected), and P0403 (EGR Circuit Malfunction).

Replacing the EGR Valve

  1. Locate the EGR Valve: It’s usually mounted on the engine, near the throttle body.
  2. Disconnect the Battery: Always disconnect the battery before starting the replacement process.
  3. Remove the Vacuum Line: Carefully disconnect the vacuum line from the EGR valve.
  4. Unbolt the EGR Valve: Use a wrench to remove the bolts securing the EGR valve to the engine.
  5. Remove the Old Gasket: Take off the old gasket from the engine where the EGR valve sits.
  6. Clean the Surface: Clean any residue or carbon buildup where the EGR valve was mounted.
  7. Install the New Gasket: Place a new gasket on the engine.
  8. Install the New EGR Valve: Position the new EGR valve onto the gasket and secure it with bolts.
  9. Reconnect the Vacuum Line: Attach the vacuum line back to the new EGR valve.
  10. Reconnect the Battery: Once everything is back in place, reconnect the battery.
  11. Test the Car: Start the engine and observe if the check engine light goes off and if the engine runs smoothly.

Final Thoughts

Always remember, if you’re unsure or uncomfortable with performing these steps, it’s best to consult a professional mechanic. Regular maintenance can save a lot of time and money in the long run.