Fuel Systems Flashcards
How do you inspect and service fuel lines and tubing?
Check for leaks, cracks, or blockages in the fuel lines. Replace any damaged sections, and ensure all connections are tight.
What are the different fuel filter designs and mountings?
Fuel filters can be inline, canister-style, or integrated with the fuel pump, typically mounted along the fuel line.
How do you remove and replace a fuel filter?
Relieve fuel system pressure, disconnect the fuel lines, remove the old filter, and replace it with a new one, ensuring proper mounting and seal.
How does an electric fuel pump circuit work?
The electric fuel pump is activated by the fuel pump relay, which sends power to the pump when the ignition is turned on, pumping fuel to the injectors.
How do you conduct a pressure and volume output test on an electric fuel pump?
Attach a pressure gauge to the fuel line and measure the fuel pressure. Then, measure the fuel volume to ensure it meets manufacturer specifications.
How do you service and test an electric fuel pump?
Inspect for power and ground at the pump, check fuel pressure output, and verify that the pump is delivering the correct fuel volume and pressure.
What is the basic composition of gasoline?
Gasoline is primarily composed of hydrocarbons, with additives for engine performance, fuel stability, and emissions control.
Why are materials added to gasoline to make it more efficient?
Additives such as detergents, antioxidants, and oxygenates improve combustion efficiency, reduce carbon deposits, and reduce emissions.
What are common substances used as oxygenates in gasoline, and what do they do?
Oxygenates like ethanol and MTBE are added to gasoline to increase the oxygen content, promoting cleaner combustion and reducing emissions.
How is the quality of a fuel tested?
Fuel quality can be tested by measuring its octane rating, checking for contaminants, and performing tests on volatility, density, and sulfur content.
What are the advantages and disadvantages of various alternative fuels?
Alternative fuels like ethanol, propane, and natural gas offer cleaner emissions but may have limitations in energy density, availability, or cost.
What is the difference between diesel fuel and gasoline?
Diesel fuel has a higher energy density, is less volatile, and has different combustion characteristics compared to gasoline. Diesel engines use compression ignition, while gasoline engines use spark ignition.
What are common types of fuel injection used on diesel engines?
Diesel engines typically use direct injection (DI) or common rail direct injection (CRDI), which injects fuel directly into the combustion chamber under high pressure.
What techniques are used to allow current diesel engines to meet emission standards?
Techniques include exhaust gas recirculation (EGR), selective catalytic reduction (SCR), and diesel particulate filters (DPF) to reduce NOx and particulate emissions.
What steps should you take to perform a no-start diagnosis?
Check for fuel, spark, and air supply, inspect the ignition system, fuel system, and compression, and use diagnostic tools like a scan tool or multimeter.
How do you determine the cause of an engine misfire?
Check for fuel, ignition, and air issues, perform a compression test, and inspect components like spark plugs, injectors, and ignition coils.
How do you test ignition system components using a voltmeter, ohmmeter, and test light?
A voltmeter measures voltage, an ohmmeter checks resistance, and a test light confirms the presence of voltage or current at components like the ignition coil or spark plugs.
How do you perform a visual inspection of ignition system components?
Inspect spark plugs, ignition wires, coils, and connections for wear, damage, or corrosion that could lead to misfires or ignition issues.
What is the effect of incorrect ignition timing?
Incorrect ignition timing can cause engine misfires, poor performance, knocking, or excessive exhaust emissions.
How do you check and set ignition timing?
Use a timing light to check the timing marks on the crankshaft pulley and adjust the timing as needed using the distributor or timing control module.
How do you diagnose engine misfiring on electronic ignition-equipped engines?
Check for spark at each cylinder, inspect injectors and sensors, test the ignition system, and ensure the correct air-fuel mixture.
What are the three basic types of ignition systems?
The three basic types are conventional ignition systems (points and condenser), transistorized ignition systems, and electronic ignition systems.
What are the two major electrical circuits used in all ignition systems?
The primary circuit (from the battery to the coil) and the secondary circuit (from the coil to the spark plugs).
How do ignition coils, spark plugs, and ignition cables operate?
The ignition coil transforms low voltage into high voltage, which is sent through ignition cables to spark plugs, where it ignites the air-fuel mixture.
