Understanding the BMW E90 Starter System
The starter system in the BMW E90 comprises several key components that work together to start the engine. Understanding these parts can help you diagnose issues more effectively.
Key Components of the Starter System
1. Starter Motor: This is the primary component that turns the engine over. It receives electrical power from the battery and converts it into mechanical energy.
2. Starter Relay: The relay acts as a switch that directs power from the battery to the starter motor when the ignition is turned on.
3. Ignition Switch: Located in the steering column, the ignition switch allows the driver to start the vehicle. When turned, it sends a signal to the starter relay.
4. Battery: A healthy battery is essential for the starter to function correctly. It provides the necessary electrical power to initiate the engine.
5. Flywheel: The starter motor engages with the flywheel, which is attached to the engine's crankshaft. This connection is vital for the engine to start.
Common Problems with the BMW E90 Starter
While the starter system in the BMW E90 is generally reliable, several common problems can arise, leading to difficulty in starting the vehicle.
Symptoms of a Failing Starter
- Clicking Sound: When you turn the ignition key, you may hear a clicking noise, indicating that the starter motor is not engaging fully.
- Engine Won't Start: If the engine does not crank when you turn the key, it may be due to a faulty starter motor or relay.
- Intermittent Starting Issues: The car may start sometimes but fail on other occasions, suggesting a problem with the starter or electrical connections.
- Burning Smell: A burning smell can indicate that the starter motor is overheating, possibly due to electrical issues.
- Dashboard Warning Lights: Warning lights may illuminate, indicating potential problems with the electrical system, including the starter.
Troubleshooting BMW E90 Starter Issues
If you experience any of the symptoms mentioned above, troubleshooting the starter system is the next step. Here’s a structured approach to diagnose the problem.
Step-by-Step Troubleshooting Guide
1. Check the Battery:
- Ensure the battery is fully charged. A weak battery can lead to starting issues.
- Inspect the battery terminals for corrosion or loose connections.
2. Test the Starter Relay:
- Locate the starter relay in the fuse box.
- Use a multimeter to check if the relay is functioning properly or swap it with another relay of the same type to test.
3. Inspect the Ignition Switch:
- Confirm that the ignition switch is working correctly. You can test the switch with a multimeter to check for continuity.
4. Examine Wiring and Connections:
- Inspect wiring connected to the starter motor and relay for damage or loose connections.
5. Test the Starter Motor:
- If all other components are functioning correctly, the starter motor itself may be faulty. You can perform a bench test or consult a mechanic.
Replacing the BMW E90 Starter
If you determine that the starter motor is the culprit, replacing it can be a straightforward process if you have some mechanical skills. Here’s how to go about it.
Tools and Materials Needed
- Socket set
- Wrench set
- Screwdrivers
- Jack and jack stands
- New starter motor
- Battery terminal cleaner (if needed)
Replacement Steps
1. Safety First:
- Disconnect the negative terminal of the battery to prevent electrical shocks.
2. Raise the Vehicle:
- Use a jack to lift the car and secure it with jack stands for safety.
3. Locate the Starter Motor:
- The starter is typically located on the lower side of the engine, near the transmission.
4. Remove the Old Starter:
- Disconnect the electrical connections to the starter motor.
- Remove the mounting bolts securing the starter to the engine block.
- Carefully take out the old starter motor.
5. Install the New Starter:
- Position the new starter in place and secure it with mounting bolts.
- Reconnect the electrical connections.
6. Reassemble and Test:
- Lower the vehicle and reconnect the battery terminal.
- Turn the ignition key to test the new starter.
When to Seek Professional Help
While many DIY enthusiasts can replace the starter, certain situations may warrant professional assistance. Consider consulting a mechanic if:
- You lack the tools or experience to perform the replacement.
- The starter issue is part of a larger electrical problem.
- There are complications during the replacement process.
Conclusion
The BMW E90 starter is a vital part of the vehicle’s starting system. By understanding its components, common issues, and replacement process, you can maintain your BMW E90 in optimal condition. Regular inspections and timely replacements can save you from unexpected breakdowns and costly repairs. Whether you decide to tackle the problem yourself or seek professional help, addressing starter issues promptly will ensure your BMW E90 continues to perform at its best.
Frequently Asked Questions
What are common symptoms of a failing BMW E90 starter?
Common symptoms include a clicking noise when turning the key, engine not cranking, dimming dashboard lights when attempting to start, and intermittent starting issues.
How can I test if my BMW E90 starter is faulty?
You can test the starter by checking the battery voltage, inspecting the starter relay, and using a multimeter to measure voltage at the starter while attempting to crank the engine.
What tools are needed to replace the starter on a BMW E90?
You'll need basic hand tools such as a socket set, wrenches, a ratchet, and possibly a torque wrench. An extension and a universal joint may also be helpful for hard-to-reach bolts.
Can a bad starter drain the battery in a BMW E90?
Yes, a bad starter can drain the battery if it remains engaged or draws excessive current, leading to a dead battery over time.
What is the average cost of replacing a starter in a BMW E90?
The cost of replacing a starter in a BMW E90 typically ranges from $300 to $800, including parts and labor, depending on the service provider and location.
