What causes the engine to turn but can't start

Experienced drivers have, at some point, faced challenging situations. Turning the key causes the vehicle to crank, but it does not start. The frustration accompanying such situations leaves the drivers with nasty opinions about cars.

Luckily, there is a remedy if the car turns but won't start. First, we must understand the root causes of this problem. We need to understand that the starter cranks the engine when the key turns in the ignition. Technically, a faulty starter will be one of the causes of this problem.

Other issues may cause engine starting problems, including insufficient fuel pressure, bad timing and ignition coil faults.

Spark problems

The spark plug is connected to an ignition coil. The coil draws energy from the car battery and converts it to a high voltage. This voltage delivers a spark that ignites the fuel. The engine can crank but not start if the spark plug, ignition coil or connections are faulty.

Poor timing is another issue that affects the spark. It causes the cylinders to fire at irregular intervals. That way, the fuel supply is out of sync with the spark delivered by the ignition coil. It is common if the camshaft position sensor is damaged.

A car can turn but not start if the engine is flooded.

To resolve spark problems, perform a comprehensive visual inspection. Check the distributor cap for any faulty connections. Use a spark tester to check for the quantity of arc produced by the spark plug. If the ignition challenge is due to a flooded engine, remove the spark plugs. Dry them before retrying the ignition.

Interrupted fuel flow

There could be insufficient fuel flow to the engine. Lack of fuel flow occurs if the car has a faulty fuel pump, dirty fuel filter, empty fuel tank or a defective fuel injector.

Remember that ignition occurs when the air-fuel mixture attains a specific pressure. It will be difficult to start the car if the fuel pressure is low. The low fuel pressure occurs if the pump is faulty and cannot supply fuel at the requisite pressure. The fuel pump should buzz when cranking the car.

You can confirm the fuel supply to the engine by using a screwdriver on each injector. A firing injector should generate a faint ticking sound. In some car models, ignition after an impact can be difficult. The inertia switch activates and prevents any further flow of fuel.

Poor compression

Engine performance depends on the compression of the cylinders. Unbalanced cylinder compression causes lair leakage from the cylinder past the compression ring, leaving insufficient air for the combustion cycle. Low compression means the cylinder is incapable of turning the crankshaft.

Compression problems increase if the timing belt is faulty. Use a compression gauge to test cylinders and estimate the amount of air leakage from each.

Power supply problems

The engine may turn but not start if there is an underlying power issue. It could be a weak starter that draws excess current from the battery, leaving it with a low voltage that cannot power injection and ignition components. A noisy starter is an indicator of a power problem.

A weak battery is another component that can cause engine starting problems. Check the battery voltage, and confirm the quality of electrical connections and the state of different fuses.

Final words

There are several ways to troubleshoot starting problems in the car. Spray some ignition fluid at the throttle. Try igniting it after spraying some fuel on the throttle.

An engine that starts but stops a short while later could be lacking fuel. If there is fuel and it does not start completely, then there is low compression.

Do not crank the vehicle repeatedly. If normal troubleshooting does not work, use a scan tool to unearth underlying problems.