How Do You Know If A Starter Is Going Bad
So, you're hearing some funny noises when you try to crank your engine, or maybe it's just refusing to turn over at all. Chances are, your starter motor is on the fritz. Knowing how to diagnose a failing starter can save you time, money, and a whole lot of frustration. This article will walk you through the tell-tale signs, the diagnostic procedures, and what you can do to confirm your suspicions.
Understanding the Starter System
Before diving into the symptoms, let's briefly recap how the starter system works. The starter motor is an electric motor responsible for cranking your engine until it reaches a speed where it can sustain combustion on its own. Key components include:
- Starter Motor: The primary unit that spins the engine.
- Solenoid: An electromagnet that engages the starter's pinion gear (small gear) with the engine's flywheel (or flexplate in automatic transmissions) and closes the circuit to send high current to the motor.
- Battery: Provides the electrical power to drive the starter.
- Ignition Switch: Sends the signal to activate the solenoid when you turn the key.
- Wiring & Relays: Connect all the components and ensure proper power distribution.
A failure in any of these components can lead to starting problems, but we'll focus on identifying issues specific to the starter itself.
Common Symptoms of a Failing Starter
Here are the most common symptoms indicating a potential starter motor problem:
1. Clicking Noise, But No Crank
This is perhaps the most frequent symptom. When you turn the key, you hear a single *click* or a series of rapid clicks. This usually points to a problem with the solenoid. The solenoid is receiving the signal to engage, but either it doesn't have enough power to fully engage and throw the pinion gear, or the contacts inside are worn and failing to complete the high-current circuit to the starter motor. Low battery voltage is a common culprit here, so always rule that out first (more on that later). A bad starter relay can cause a similar issue, preventing sufficient current from reaching the solenoid.
2. Grinding Noise During Start-Up
A horrible grinding sound usually indicates that the pinion gear isn't properly meshing with the flywheel/flexplate. This can be due to worn teeth on either the pinion gear or the flywheel/flexplate. The solenoid might be failing to fully extend the pinion gear, or the gear itself might be damaged. Continued attempts to start the engine with this grinding can cause significant damage to both the starter and the flywheel/flexplate.
3. Engine Fails to Crank at All
Sometimes, the engine simply does nothing when you turn the key. There is no clicking, no grinding, just silence. This can be caused by a completely dead starter motor, a faulty solenoid, a bad ignition switch, a broken wire, or a dead battery. It’s crucial to systematically rule out other possibilities before condemning the starter. Use a multimeter to check for voltage at the starter solenoid when the ignition switch is in the "start" position. If you have voltage, the problem is likely within the starter motor or solenoid itself.
4. Starter Stays Engaged After Engine Starts
This is a less common but potentially damaging symptom. If the starter motor continues to run even after the engine has started, it's likely the solenoid is sticking. This can lead to the starter motor over-revving and self-destructing, as well as damaging the flywheel/flexplate. Turn the engine off immediately if this occurs. Don't try to restart the car until you've addressed the issue.
5. Intermittent Starting Problems
Sometimes, the car starts perfectly fine, and other times it struggles or refuses to start altogether. This can be a sign of a starter that's on its way out. The brushes inside the starter motor might be worn, or the solenoid might be intermittently failing. These intermittent issues can be particularly frustrating to diagnose, as the problem might not be present when you're trying to troubleshoot. Take detailed notes about when the problem occurs (e.g., hot weather, cold weather, after the car has been sitting for a long time).
6. Smoke or Burning Smell
If you notice smoke coming from the starter area or a burning smell after attempting to start the engine, this is a serious sign of a failing starter. The starter motor is likely overheating due to excessive current draw or internal damage. Disconnect the battery and investigate the issue immediately to prevent further damage or a potential fire.
Diagnostic Procedures
Once you've identified some potential symptoms, it's time to perform some diagnostic tests:
1. Battery Voltage Test
The first step is to rule out a weak battery. Use a voltmeter to check the battery voltage. A fully charged battery should read around 12.6 volts. If the voltage is significantly lower (e.g., below 12 volts), charge the battery fully and retest. If the battery still doesn't hold a charge, it might be the culprit, not the starter. Also, check the battery terminals and cables for corrosion. Clean them thoroughly with a wire brush if necessary.
2. Voltage Drop Test
A voltage drop test measures the voltage loss across a circuit. This can help identify corroded connections or damaged wires. To perform a voltage drop test on the starter circuit, connect the voltmeter leads to the positive battery terminal and the starter motor's positive terminal (while someone attempts to start the car). A voltage drop of more than 0.5 volts indicates excessive resistance in the circuit.
Repeat the test on the ground side, connecting the voltmeter leads to the negative battery terminal and the starter motor's housing. Again, a voltage drop of more than 0.5 volts indicates a problem with the ground connection.
3. Starter Solenoid Test (Jump Test)
Safety Note: This test involves bypassing some of the safety features of the starting system. Ensure the vehicle is in park (automatic) or neutral (manual), and the parking brake is firmly engaged.
To test the solenoid directly, you can perform a jump test. Use a heavy-gauge jumper cable to directly connect the positive terminal of the battery to the small "S" terminal on the starter solenoid. This bypasses the ignition switch and sends power directly to the solenoid. If the starter engages and cranks the engine, the problem is likely in the ignition switch, wiring, or starter relay. If the starter still doesn't engage, the solenoid itself is likely faulty.
4. Visual Inspection
Carefully inspect the starter motor for any visible signs of damage, such as cracks, broken wires, or corrosion. Check the pinion gear for worn or broken teeth. If you can access the flywheel/flexplate, inspect its teeth as well. A borescope can be helpful for this. Also, check the wiring to the starter. Look for frayed or damaged wires and corroded connections.
When to Replace the Starter
If you've performed the diagnostic tests and confirmed that the starter motor is indeed faulty, it's time for a replacement. While some people attempt to rebuild starter motors, it's generally more cost-effective and reliable to replace the entire unit with a new or remanufactured starter. Be sure to purchase a starter that is specifically designed for your vehicle's make, model, and engine. If you are unsure of the procedure, consult a qualified mechanic to perform the replacement.
Important: Always disconnect the negative battery cable before working on the starter system to prevent accidental shorts and electrical shocks.