A8 Engine Performance Practice Test Graded A+

A8 Engine Performance Practice Test Graded A+ PCV System What should happen when performing a PCV valve test? The valve should rattle when shaken back and forth. What is the purpose of the PCV valve test? To check if the valve is functioning properly. What tool is used to perform the PCV valve test? A rattle test. What happens when performing a snap-back test on a PCV valve? The plunger snaps back when pressed with the thumb. What tool is used to check for crankcase vacuum at idle? A water manometer. Ignition Module What could cause ignition module failure? Loose module mounting screws. What would not cause ignition module failure? A fouled spark plug. Fuel System What would happen if the fuel return hose is partially restricted? Fuel pressure would be higher than normal, causing poor fuel economy without affecting drivability. What would happen if the fuel regulator is stuck open? Fuel pressure would be lower, possibly causing a no-start condition, but not affecting fuel economy. EGR System What is the purpose of the EGR system? To lower combustion chamber temperature. What would happen if the EGR system is inoperative? The engine would run hotter, causing spark knock and elevated oxides of nitrogen (NOx) readings. Coil What type of voltage does the ignition coil produce? Three types: required voltage, available voltage, and reserve voltage. What could happen if there is not enough reserve voltage? The engine would miss during acceleration. Diagnostic Procedure What is the first step in any diagnostic procedure? Verify the customer complaint. Fuel Pressure What would happen if low fuel pressure were present in all cylinders? All cylinders would be affected. What could cause a multiple-cylinder misfire code? Low fuel pressure, a leaking EGR valve, or a burnt valve. Gas Cap What could happen if a non-vented gas cap were used on a vented gas cap-equipped vehicle? The vehicle could starve for fuel due to vacuum locking in the fuel tank, or the gas tank could collapse. Secondary Air System What is the purpose of the secondary air system? To inject additional air into the catalytic converter to help oxidize HC and CO emissions. Would secondary air injection lean out the air/fuel mixture? No, it does not lean out the air/fuel mixture. C. The resistance value of the primary circuit in the coil is crucial for good secondary circuit operation. A resistance measurement of the primary to secondary measures the secondary winding resistance and is an important test. The secondary ignition system is a high-voltage, low-amperage circuit, While the secondary voltage readings are important, the amperage is not measured. The primary amperage is very important. If the primary amperage was too low, then the secondary voltage would be low. ️Which of the following is LEAST LIKELY to be a test that would be performed on an ignition coil? A. Resistance primary to primary B. Resistance primary to secondary C. Secondary circuit amperage D. Primary circuit amperage