Whether you are headed to an important business meeting or just off to the beach, it's a big pain when your car fails to start. The starter cranks the engine, allowing fuel to enter the cylinders and power your vehicle. Sometimes, starter problems are difficult to figure out. Before you head out to purchase a new one, you should make sure that the starter is actually the problem, not just the battery. There are a few steps you can take to test the function of your car starter and save time and money.
Inspect the battery. You should always check your battery first, because dead or sulfated batteries are often misdiagnosed as car starter problems. If the battery is low on power, dead or badly corroded, it may be responsible for your car troubles.
Wire the battery past the solenoid. The solenoid can be found either directly on top of your starter or nearby, and it is usually connected to the positive battery cable. This part carries power from your starter to the battery and it can often become disconnected or corroded. Wire the starter to the battery using a jumper cable and making sure to bypass the solenoid. If the starter motor spins, then the problem is a faulty solenoid.
Perform a no-load free running test on your starter. This will tell you the rpm speed of the part. Clamp the starter lightly in a bench vice and attach the negative cable to its housing. The positive cable goes on the positive battery lead found on your starter. The motor should spin at around 2500 rpm. If it turns too slowly or remains still, you will have to replace the starter.
Inspect the teeth on the flywheel. If these teeth are broken or damaged, the starter will be unable to crank the engine and start the car. Turn off the car and manually turn the engine fan 1/4 of a turn. Attempt to start your car again and listen. If the starter begins cranking and stops, the flywheel teeth are broken and need to be replaced. If the starter does not become stuck on the flywheel, but makes a grinding noise, the problem is probably with the starter drive.
Check your gears for wear and damage. If you notice that your starter will not shut off or it won't engage, it may be a result of faulty pinion or ring gears. Replace worn down and corroded gears as needed.
