Common Causes

When a Land Rover Discovery turns over but won't start, several issues could be at play:

  • Fuel system problems: This includes a faulty fuel pump, clogged fuel filter, or issues with the fuel injectors.
  • Ignition system failures: Spark plug issues, faulty ignition coils, or a malfunctioning crankshaft position sensor can prevent starting.
  • Electrical issues: Problems with the battery, alternator, or starter motor can cause starting difficulties.
  • Security system glitches: The immobilizer may be preventing the engine from starting.

Fuel System Troubleshooting

Start by checking the fuel system:

  • Listen for the fuel pump when turning the key to "On" position. A humming sound indicates it's working.
  • Check the fuel pressure using a fuel pressure gauge.
  • Inspect the fuel filter for clogs and replace if necessary.
  • Test fuel injectors for proper operation.

If these checks reveal no issues, move on to the ignition system.

Ignition System Checks

Examine the ignition system components:

  • Inspect spark plugs for wear or damage and replace if needed.
  • Test ignition coils for proper resistance and output.
  • Check the crankshaft position sensor for correct operation.
  • Verify the camshaft position sensor is functioning correctly.

Electrical System Inspection

Ensure the electrical system is functioning properly:

  • Test the battery voltage (should be above 12.6 volts).
  • Check all battery connections for corrosion or looseness.
  • Inspect the alternator for proper charging (13.5-14.5 volts while running).
  • Verify the starter motor is engaging correctly.

Security System Issues

The immobilizer system can sometimes prevent starting:

  • Try using the spare key to rule out a faulty key fob.
  • Check for any security system warning lights on the dashboard.
  • Consider having the immobilizer system scanned for faults.

Professional Diagnosis

If these steps don't resolve the issue, consider seeking professional help:

  • Use a diagnostic scan tool to check for error codes.
  • Perform a compression test to rule out internal engine problems.
  • Conduct a fuel pressure test to verify proper fuel delivery.

Remember, Land Rover Discoveries can have complex electrical systems. If you're unsure about any step, it's best to consult a qualified mechanic specializing in Land Rover vehicles.

FAQs About Land Rover Discovery Starting Issues

    • Can a bad fuel pump cause my Discovery to crank but not start?
      Yes, a faulty fuel pump can prevent fuel from reaching the engine, causing a no-start condition even when the engine cranks.
    • How often should I replace the fuel filter in my Land Rover Discovery?
      It's recommended to replace the fuel filter every 30,000 to 50,000 miles, but check your owner's manual for specific intervals.
    • Could a dead key fob battery prevent my Discovery from starting?
      While unlikely, a dead key fob battery could interfere with the immobilizer system. Try using the spare key or holding the key fob close to the start button.