Questions and Answers
Injectors in a multi-point injection system usually spray atomized fuel very close to the:
inlet valve
When fitting a knock sensor it should always be:
set to the specific torque setting
A manifold absolute pressure (MAP) sensor measures:
induction air vacuum
The name of the component which rotates in a distributor cap is:
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One benefit of using a coil per plug system is that the:
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What three harmful gases will the catalyst convert?
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After a faulty fuel injection air mass meter has been replaced it is often necessary to:
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What equipment would be used to check the operational efficiency of replaced MPI fuel injectors?
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When checking petrol Multi Point Injection system pressure, the test should be carried out on the:
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Tuned lengths of both inlet and exhaust manifolds are used to greatly improve:
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When injectors operate individually, this is called:
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A faulty oxygen sensor will affect the:
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What effect would an open circuit coolant temperature sensor have on an engine management system?
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In which one of the following components would the ignition pulse generator be located?
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Which one of the following cylinder heads is more likely to cross thread a spark plug?
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If a car fails to crank when starting, which one of the following would normally be the first to be tested?
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An accurate method of checking ignition timing on an engine with a coil per plug system is to fit a:
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Glowing red hot spark plugs often cause an engine running fault called:
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The term pinking refers to a noise heard in the engine when it suffers from being:
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A common cause of poor starting in damp conditions is:
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Replaced exhaust components must comply with:
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Which one of the following items of equipment would be used to check the operational efficiency of a replaced catalyst converter?
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One method of reducing exhaust noise is to use:
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A resonator box is fitted to an exhaust system to:
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Which one of the following can cause internal corrosion of an exhaust system?
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When removing and replacing light vehicle diesel injectors, which other components should always be replaced?
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Name one design difference between the SPI and MPI fuel systems:
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Where is a common place on a four-stroke petrol engine for the ignition crank angle sensor to be located?
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One purpose of a resilient mounting on an exhaust system is to:
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What is the purpose of an air filter?
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An EOBD system warns of an Electronic Fuel Injection running fault by:
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Which one of the following engine running test methods would determine whether a light vehicle electronically controlled diesel injector was working?
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When retrieving fault codes, what equipment should initially be connected to the OBD socket?
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A coolant temperature sensor with a Negative Temperature Coefficient (NTC) will:
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When the petrol fuel to air ratio control is monitored by exhaust Lambda sensors, it is known as:
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Which one of the following is an important action before removing a spark plug?
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When examining spark plugs, a white speckled insulator tip would indicate a very:
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A simple test for the correct running of an engine is to look at the:
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Which one of the following sensors sends signals to the engine management system for ignition timing adjustments?
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Which engine stroke does the spark plug normally fire on?
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What would a black soot covered spark plug indicate?
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Before replacing an exhaust manifold it must be ensured that:
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Which one of the following light vehicle exhaust components would normally be fitted to a diesel engine but not fitted to a petrol engine?
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Fuel and air swirl in a combustion chamber is assisted by:
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Which one of the following is a symptom of a blocked exhaust?
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For what reason do turbocharger bearings require constant cooling?
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Which component distributes high voltage to the distributor cap segments?
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Study Notes
Fuel Injection Systems
- Multi-point injection systems use injectors that spray atomised fuel close to the inlet valve.
- Sequential operation of injectors allows for improved fuel efficiency by activating each injector individually.
Sensors and Monitoring
- A manifold absolute pressure (MAP) sensor measures induction air vacuum, essential for fuel management.
- Knock sensors must be set to specific torque settings during installation to ensure proper operation.
- Oxygen sensors impact the air/fuel ratio and must be functional for optimal engine management.
- Coolant temperature sensors with a Negative Temperature Coefficient (NTC) decrease resistance as the temperature rises, aiding in accurate engine control.
Emissions Control
- Catalysts convert harmful gases: hydrocarbons (HC), carbon monoxide (CO), and nitrogen oxides (NOx).
- Emissions testers are used to check the operational efficiency of replaced multi-point fuel injectors.
- Exhaust gas analysers assess catalyst converter efficiency.
Ignition System
- The rotor arm rotates within the distributor cap to distribute high voltage.
- Spark plugs should be examined for condition; white speckled insulator indicates overheating, while black soot suggests a rich fuel mixture.
- Ignition timing can be checked accurately using a hand-held ECU interface scanner.
Exhaust System
- Exhaust components must meet legal noise requirements after replacement.
- Resonator boxes and baffle plates help reduce sound levels in the exhaust system.
- Internal corrosion of exhaust systems can be caused by combustion by-products.
Maintenance Practices
- Replace injector sealing washers when changing diesel injectors to prevent leaks.
- Clean all mating surfaces and replace gaskets before installing a new exhaust manifold.
- Dust and debris should be removed before spark plug replacement to avoid contamination.
Engine Performance and Diagnostics
- A faulty fuel injection air mass meter requires erasing fault codes after replacement to reset the system.
- EOBD systems alert drivers to Electronic Fuel Injection issues by illuminating warning lights.
- Turbocharger bearings require constant cooling due to their proximity to the exhaust manifold.
Miscellaneous
- A particulate filter is typically found in diesel engines but not in petrol engines.
- Cylinder head design facilitates fuel and air swirl in the combustion chamber, enhancing combustion efficiency.
- Symptoms of a blocked exhaust include a total lack of engine power.
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Description
Test your knowledge with these flashcards from Motor Vehicle Unit 172. Each card contains essential definitions and terms related to automotive technology and systems. Perfect for students looking to reinforce their understanding of multi-point injection systems, sensors, and more.
