My car won't start. What's wrong?
P Paul Coker

My car won't start. What's wrong?

Aug 29, 2024

Why won't my car start? It was going fine when I drove home last night..

Starting faults can be caused by many different things, from a flat or faulty battery, a wiring or immobilizer fault, a faulty starter motor, the list goes on.

In this blog we will cover the basics and most common issues causing your vehicle or engine not to start.

If you turn your key on, try start your engine and it doesn't start, you will likely have one of 4 symptoms.

1 Slow cranking engine, sounds like it's struggling, not turning over fast enough to start.

2 No sound, or a soft tick.

3 The starter seems to be spinning over, you can here this, but it's not 'engaging' and turning the engine over.

4 Big clack when you turn the key to start, but nothing more than that noise.

Let's go over these and talk about the most likely causes of these symptoms.

1 The most common and likely cause of slow cranking is a dead, or a flat battery. It can also be a failed starter motor, or a very unlikely cause is a tight engine.

The quickest way to check for this is use a good battery, jumper pack, or jumper cables. Note, you must know these are in good serviceable condition.

If your engine starts as normal with a jumper connected. You have a bad battery. You will need to charge and test the battery, or replace it.

If the battery is flat, you'll want to check the alternator is charging ok. Test the voltage across the battery once you've jumpstarted the engine, if the voltage is below 13 volts, you have a charging/alternator fault. Have the charging system/alternator tested. 

If the jumper doesn't make much difference, you most likely have a faulty starter motor.

2 The most common and likely cause of no sound or a soft tick is a faulty starter motor (brushes worn out, or a faulty solenoid).

This can also be due to a wiring, immobilizer or ignition switch fault.

Use a DC voltmeter and test the voltage at the small wire at the solenoid while cranking the key. You should get 10.5 or more volts while the key is on the start position.

If there is no or low voltage, you have a wiring, immobilizer or ignition switch fault.

3 If the starter sounds like it is spinning over but not engaging, this is the starter drive clutch slipping. The starter will need to be repaired or replaced.

4 The big clack and nothing more, this is a starter motor, or low voltage at solenoid energize terminal fault. Check for 10.5 volts or more at the small wire on the solenoid while turning the key to the start position. If less than 10.5 volts, you have a wiring fault. If the voltage was above 10.5 volts, have the starter repaired or replaced.

This covers the basics of the faults you'll see when your engine doesn't start.

If you are unsure, have someone help you to test it before you start replacing batteries or starter motors.

Cheers

Paul

StartnCharge

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