Question 1

Winter blend gasoline ________.

Accepted Answer

Winter blend gasoline has a higher Reid Vapor Pressure (RVP) which means it vaporizes more easily to ensure proper engine starting and operation in cold weather. Using it in warm weather can indeed cause driveability problems due to excessive vaporization.

Question 2

Vapor lock can occur ________.

Accepted Answer

Vapor lock can occur when a fuel line is restricted or as a result of excessive heat near fuel lines, causing the fuel to vaporize within the fuel line and preventing the flow of liquid fuel to the engine.

Question 3

Which of these symptoms may be caused by excessive ethanol in the fuel?

Accepted Answer

Excessive ethanol in fuel can lead to rough idling or stalling due to its impact on the combustion process and fuel system components.

Question 4

Reformulated gasoline contains at least ________ percent oxygen by weight.

Accepted Answer

Reformulated gasoline must contain at least 2 percent oxygen by weight to ensure more complete combustion, reducing harmful emissions.

Question 5

Adding up to 10% ethanol to gasoline can also increase the fuel's ________.

Accepted Answer

Adding up to 10% ethanol to gasoline increases the fuel's volatility because ethanol has a higher vapor pressure than gasoline, which makes the fuel-air mixture more volatile and easier to ignite.

Question 6

If regular-grade gasoline is used in an engine designed for premium gasoline, what might result?

Accepted Answer

Using regular-grade gasoline in an engine designed for premium gasoline can lead to reduced engine power and reduced fuel economy because the engine is optimized to operate with the higher octane level of premium gasoline.

Question 7

Which of these is NOT a possible effect of using gasoline with alcohol additives?

Accepted Answer

Alcohol additives in gasoline can lead to reduced CO emissions, increased volatility, and increased octane, meaning all of these effects are possible outcomes of using such additives.

Question 8

To avoid problems with the variation of gasoline, all government testing uses as a fuel during testing procedures.

Accepted Answer

Indolene is used in government testing as a fuel because it has a consistent quality that helps in avoiding the problems associated with the variation of gasoline. This consistency is crucial for accurate and reliable testing results.

Question 9

Avoid topping off the fuel tank because ________.

Accepted Answer

Topping off the fuel tank can lead to fuel entering the vapor recovery system and saturating the charcoal canister, which is designed to absorb and store fuel vapors to prevent them from being released into the atmosphere. Overfilling the tank can compromise this system's functionality.

Question 10

Using ethanol-enhanced or reformulated gasoline can result in reduced fuel economy.

Accepted Answer

Ethanol contains less energy per gallon than gasoline, which means that vehicles using ethanol-blended fuels typically experience a reduction in miles per gallon compared to using pure gasoline.

Question 11

Pump octane is rated by ________.

Accepted Answer

The answer of Pump octane is rated by ________.
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Question 12

A gasoline with a high driveability index is ________.

Accepted Answer

A high driveability index (DI) indicates that the gasoline has a balanced volatility, meaning it is less volatile than gasoline with a lower DI. This balance helps ensure good engine performance across a range of temperatures without causing issues like vapor lock or hard starting.

Question 13

Technician A says that volatility is a measure of how easily gasoline evaporates. Technician B says that Reid Vapor Pressure (RVP) is one way to express how volatile a gasoline mixture is. Which technician is correct?

Accepted Answer

Volatility refers to the ease with which a liquid fuel like gasoline evaporates, which is what Technician A describes. The Reid Vapor Pressure (RVP) is indeed a common measure of a fuel's volatility, as stated by Technician B.

Question 14

Technician A says that driveability problems may be avoided by using "Top Tier" gasoline. Technician B says that driveability problems may be avoided by always keeping the fuel tank at least one-quarter full. Which technician is correct?

Accepted Answer

Both technicians are correct. "Top Tier" gasoline contains detergents and additives that can help prevent engine deposits that lead to driveability problems. Keeping the fuel tank at least one-quarter full helps avoid issues with the fuel pump overheating and potential contamination from sediment at the bottom of the tank.

Question 15

Technician A says that using lower octane fuel in vehicles designed for premium fuel will cause serious engine damage. Technician B says that some octane boosters will cause discoloration of the porcelain on the spark plug tip. Which technician is correct?

Accepted Answer

Technician B is correct because certain octane boosters contain chemicals that can lead to discoloration of the spark plug tip's porcelain. Using lower octane fuel than recommended may not necessarily cause serious engine damage but can lead to decreased performance and efficiency.

Quiz 66: Gasoline