Nissan Murano Will Not Start

The Nissan Murano, a stylish and comfortable crossover SUV, has carved a niche for itself since its introduction in 2002. Known for its distinctive design and smooth ride, the Murano is a popular choice for families and individuals alike. However, like any vehicle, it can experience starting problems. This article delves into the common reasons why your Nissan Murano might refuse to start, providing insights for owners, enthusiasts, and mechanics alike.

Common Causes of a Murano That Won't Start

Diagnosing a "no-start" condition in a Nissan Murano requires a systematic approach. Let's examine the most frequent culprits:

Dead or Weak Battery

This is the most common reason for a no-start situation. The battery provides the initial electrical power needed to crank the engine. Over time, batteries degrade due to age, temperature fluctuations, and parasitic drain (e.g., leaving lights on). A weak battery may have enough power to illuminate the dashboard lights, but not enough to turn the starter motor.

Symptoms: Dim headlights, slow cranking, clicking sound when turning the key, dashboard lights flickering. A healthy battery should read around 12.6 volts. Anything below 12.0 volts indicates a discharged or failing battery.

Troubleshooting: Use a multimeter to test the battery voltage. If it's low, try jump-starting the car. If the car starts with a jump, the battery likely needs replacing. Consider a battery load test at an auto parts store to determine its overall health.

Faulty Starter Motor

The starter motor is responsible for turning the engine over until it can run on its own. If the starter motor is failing, it may not be able to crank the engine, even with a fully charged battery. Starter motor problems are more common in older vehicles or those with high mileage.

Symptoms: Clicking sound when turning the key (even with a good battery), no sound at all, grinding noise during starting, or the engine cranks very slowly. Sometimes, tapping the starter motor with a hammer can temporarily get it working, indicating a problem.

Troubleshooting: Check the starter motor relay and fuse. If they're good, the starter motor itself is likely the problem. Replacing the starter motor is often necessary.

Alternator Issues

While not directly responsible for starting the car initially, a failing alternator can eventually lead to a dead battery. The alternator recharges the battery while the engine is running. If it's not functioning properly, the battery will slowly drain, eventually preventing the car from starting.

Symptoms: Dimming headlights while driving, warning lights on the dashboard (e.g., battery light), a generally weak-running engine, and eventually, a no-start condition after the car has been sitting. An alternator usually puts out between 13.5 and 14.5 volts when the engine is running.

Troubleshooting: Check the alternator's output voltage with a multimeter while the engine is running. If it's significantly below 13.5 volts, the alternator is likely faulty. Replacing the alternator is the usual solution.

Fuel System Problems

For the engine to start, it needs fuel. Problems in the fuel system can prevent fuel from reaching the engine, leading to a no-start condition. This could involve a faulty fuel pump, clogged fuel filter, or malfunctioning fuel injectors.

Symptoms: Engine cranks but doesn't start, sputtering or hesitation during starting, a noticeable lack of power while driving, or a complete absence of fuel pump noise when the ignition is turned on. Note that the Nissan Murano's fuel pump is located inside the fuel tank, making access a bit more involved.

Troubleshooting: Listen for the fuel pump priming when you turn the key to the "on" position (but before starting). Check the fuel pump relay and fuse. A fuel pressure test can confirm whether the fuel pump is delivering adequate pressure to the fuel rail. A clogged fuel filter should be replaced regularly as part of preventative maintenance.

Ignition System Malfunctions

The ignition system provides the spark needed to ignite the air-fuel mixture in the cylinders. Issues such as faulty spark plugs, ignition coils, or a crank position sensor can prevent the engine from starting.

Symptoms: Engine cranks but doesn't start, rough idling (if it does start), misfires, and a check engine light. A faulty crank position sensor can prevent the engine from even attempting to start.

Troubleshooting: Check the spark plugs for wear or damage. Use a spark tester to verify that each spark plug is receiving a spark. A diagnostic scan tool can help identify faulty ignition coils or a malfunctioning crank position sensor. A code reader is invaluable in these situations.

Immobilizer System Issues

Modern vehicles, including the Nissan Murano, are equipped with an immobilizer system to prevent theft. This system uses a chip in the key to communicate with the car's computer. If there's a problem with the immobilizer, the car won't start, even with a valid key.

Symptoms: The engine cranks but doesn't start, the security light on the dashboard may be flashing, and the car may display a "key not recognized" message.

Troubleshooting: Try using a spare key. If the spare key works, the original key may be faulty. If neither key works, there may be a problem with the immobilizer system itself, requiring professional diagnosis and reprogramming.

Other Potential Causes

While the above are the most common causes, other less frequent issues can also prevent a Nissan Murano from starting:

Faulty Crankshaft Position Sensor: This sensor provides crucial information to the engine control unit (ECU) about the engine's position. A faulty sensor can prevent the engine from starting.
Clogged Air Filter: Although less likely to cause a complete no-start condition, a severely clogged air filter can restrict airflow to the engine, making it difficult to start.
Vacuum Leaks: Large vacuum leaks can disrupt the air-fuel mixture, making the engine hard to start or causing it to stall.
Wiring Issues: Damaged or corroded wiring can interrupt the flow of electricity to critical components, preventing the car from starting.

Diagnostic Process and Tools

Diagnosing a no-start condition often requires a systematic approach and the use of various tools:

Multimeter: Used to measure voltage, current, and resistance to check battery health, alternator output, and circuit continuity.
Scan Tool (OBD-II Scanner): Reads diagnostic trouble codes (DTCs) stored in the car's computer, providing valuable clues about the source of the problem.
Fuel Pressure Tester: Measures the fuel pressure in the fuel rail to determine if the fuel pump is delivering adequate pressure.
Spark Tester: Verifies that each spark plug is receiving a spark.
Jump Starter: Provides a temporary power source to jump-start the car if the battery is weak.

Preventative Maintenance

Regular preventative maintenance can significantly reduce the likelihood of experiencing a no-start condition. Here are some key maintenance tasks:

Battery Maintenance: Regularly clean the battery terminals and check the battery voltage. Replace the battery every 3-5 years, depending on climate and usage.
Fuel System Maintenance: Replace the fuel filter at the manufacturer's recommended intervals. Use high-quality fuel and avoid letting the fuel tank run completely empty.
Ignition System Maintenance: Replace spark plugs at the recommended intervals. Inspect ignition coils for damage and replace them if necessary.
Regular Oil Changes: Ensure proper lubrication and cooling, contributing to overall engine health and easier starting.

Conclusion

A Nissan Murano that won't start can be a frustrating experience. By understanding the common causes and employing a systematic diagnostic approach, you can identify the problem and get your Murano back on the road. Remember to prioritize safety and consult a qualified mechanic if you're unsure about any repair procedures. Investing in preventative maintenance can help avoid many of these issues in the first place, ensuring years of reliable service from your Nissan Murano.