A Hyundai’s engine is compoised of various mechanical parts, sensors and other electronic parts. Any one of these parts could make a Hyundai engine shut off or stall. To understand how an engine works, you must know that each part affects another part in or on the engine. A simple sensor fail could cause the whole engine to stall.
When a Hyundai engine stalls, check the obvious first. Make sure there is fuel in the tank. Do not rely on the gas gauge, since the gas gauge can be broken. Tap the bottom of the tank with your fingers to see if it has gas in it. You should hear a dull thud if there is gas in the tank. If not, you will hear a hollow sound.
If there is gas in the tank, make sure the fuel is getting to the engine. Look for the fuel rail. There should be a Schraeder valve on the fuel rail. Uncap the Schraeder valve. Stick a Phillips screwdriver in and push the center of the Schraeder valve down while a friend turns the key on. The fuel should shoot straight up into the air. If it dribbles, either you do not have fuel getting to the rail or the pressure is very low.
If fuel is not the problem, spark can cause an engine to fail. To test for spark, remove a plug wire. Stick an extra plug (do not use the plug that is in the engine) into the end of the wire. Lay the plug on the metal part of the engine. Have a friend crank the engine over. Look for spark. If you do not see spark, the problem is in the ignition system.
Sensors and Computers
Sensors can also cause a Hyundai engine to stall or shut off. Most sensor fails will send the computer into a “limp home” mode. The car will run badly, but it will at least get you to a mechanic or home. There are some sensors that will cause a complete failure, most notably the idle air control valve. This valve senses when the vehicle’s idle goes below a certain point. Systems such as the air conditioning require horsepower to run. When the compressor comes on, the idle will drop because of the resources needed to run it. The idle air control valve turns the idle up on the car so it will not stall. If the idle control valve is dirty or has completely failed, it will not be able to change the idle on the vehicle, causing it to stall.
If the timing belt breaks while you are driving, this will cause a definite stall. The timing belt runs from the camshaft(s) to the crankshaft. Depending on the year and model Hyundai you are driving, you may have one or two camshafts. As the crank turns, the lower timing gear on the crank turns the belt, which is also mounted on the cam gears. If the cams do not turn, the valves cannot open and close. Simply put, fuel and air do not make it into the proper cylinder at the proper time, causing a shutdown.
Because of the configuration of today’s engines, the Hyundai engine, along with all other modern engines, are more difficult to diagnose without the use of a computer and an experienced mechanic.