Although vehicles break down far less often today than they did in the past, they still encounter problems from time to time. The parts and systems under the hood wear out and fail. Depending on the components, such failures may cause your engine to die, after which it refuses to restart.
While a non-starting engine is always inconvenient, it can sometimes be fixed easily. But being able to do so requires a basic understanding about how the assembly starts in the first place. When you turn the key in the ignition, voltage from your battery flows to the ignition switch. It then travels to the starter relay and starter motor, which spins to crank the engine. Whether it starts and roars to life depends on whether there is sufficient fuel, compression, and spark in the cylinders.
We’ll go through a diagnostic process below that will help you to troubleshoot a non-starting car. There are many components that may be involved, and some of them are difficult, even impossible, to check by the side of the road. However, the following provides a good place to start.
Symptoms Offer Clues To The Problem
You can learn a lot about your engine by listening closely when it fails to start. The noises you hear may help you narrow down the component causing the problem. For example, if you turn the key and hear nothing, the battery is likely involved. On the other hand, a clicking noise may imply the battery or starter. If the engine turns over, but refuses to start, the problem may involve the spark plugs or fuel system.
These and other symptoms provide valuable clues regarding the reason your car won’t start. While they may not pinpoint the faulty part, they can highlight certain areas that pose problems. This will help you to save time while troubleshooting the cause.
When The Engine Refuses To Crank
The most common issue that prevents an engine from turning over is a dead battery. Occasionally, a no-start is caused by heavy corrosion that accumulates on the battery’s posts. If the battery is not involved, the problem is likely to be found somewhere in the ignition system. When an engine fails to crank, it is usually because the assembly is not receiving sufficient voltage.
A failing ignition switch or starter motor may be causing the issue. Or, the starter solenoid (located upstream from the starter motor) may have gone bad. If any of the wires from the battery to the starter motor are frayed or loose, they too can prevent voltage from passing.
When The Engine Refuses To Start
Suppose you turn the key and hear the engine turn over, but it refuses to actually start. Here, the problem involves a lack of spark, fuel, or compression. Start troubleshooting by testing for a spark. You can purchase a basic spark tester at most auto supply stores for less than $15. If there is no spark, the problem is somewhere in the ignition system. If you can verify that a spark exists, check whether sufficient fuel is arriving in the engine.
Start with the fuel pump. Then, assuming the pump is working properly, test the pressure in the fuel line. If the pump is working, the pressure should be fine. Next, check the fuel filter to make sure it is not clogged. If it is, gasoline will be unable to pass through the filter’s media. Assuming the filter is fine, check the fuel injectors to make sure they are working.
If your engine is receiving enough fuel, the no-start must be due to a lack of compression. Check each of the cylinders with a compression tester (the tester usually costs less than $30). Insufficient compression is often caused by a timing belt that has snapped or become loose. This will affect how the intake and exhaust valves land in their seats.
A non-starting engine is always frustrating, especially since the problem seems to occur at the worst possible times. However, with a methodical approach and a little patience, you can go a long way toward troubleshooting the root cause.