Exam 19: Fuel Subsystems

In a fleet operation, when should truck drivers be instructed to refill the fuel tanks?

Which of the following fuel subsystem components would be subjected to charging pressure?

Technician A says that it is common for Caterpillar HEUI fuel systems to use a centrifugal type fuel transfer pump. Technician B says that a double-acting fuel subsystem transfer pump moves fuel on the push and pull strokes. Who is correct??

What can result from a water-in-fuel condition when the secondary filter is capable of entrapping particulate as small as one micron?

An engine with a reported lack of power (LOP) condition evidently caused by fuel starvation is being diagnosed. The specified maximum inlet restriction on the primary side of the fuel transfer pump is 7-inches HG and the circuit tests at exactly this value. Technician A says that the LOP condition is almost certainly caused by a plugged primary filter and the first step should be to change it. Technician B says that the primary side of the fuel subsystem is not responsible because it still tests within specification. Who is correct?

When priming a primary fuel filter during a routine service, which of the following is best practice?

In a typical fuel subsystem, which of the following is capable of entrapping the smallest particles suspended in the fuel?

Which of the following fuel subsystem components would typically be located closest to the fuel tank?

In a typical diesel fuel subsystem, where would the fuel subsystem charging pressure regulating valve be located?

When is the preferred time to refuel diesel fuel tanks??

What two principles are used by most fuel water separators to remove water from fuel?

?Technician A says that a diesel fuel subsystem secondary filter can plug on water causing an engine shutdown. Technician B says that when secondary fuel filter causes an engine shutdown due to fuel starvation, pouring two cans of methyl hydrate into the fuel tank should cure the problem. Who is correct?

When fuel exits a gear pump discharge port while an engine is run, what force moves more fuel into the gear pump inlet in a typical diesel fuel subsystem?

What pumping principle is used on transfer pumps on a majority of diesel engines today?

What should be used to verify the operation of a fuel tank sending unit when it is electrically disconnected?

Technician A says that secondary fuel filters can entrap particles smaller than the eye can see. Technician B says that primary filters cannot entrap particles smaller than a section of a human hair. Who is correct?

Technician A says that a diesel fuel tank plays a role as a heat exchanger in many modern diesel fuel systems. Technician B says that rectangular shaped fuel tanks can provide the same strength using thinner wall thickness than that required for cylindrical tanks. Who is correct?

Technician A says that when a diesel fuel tank is vented to atmosphere, more than half the dirt trapped by the fuel filters enters the tank through the breather. Technician B says that a fuel tank breather filter can extend the life of fuel filters. Who is correct?

What is a fuel water separator unable to remove from the fuel routed through it?

You are verifying the performance of a 240-ohm fuel tank sending unit that you have disconnected. Which of the following resistance readings is OK when the sender arm is moved to the full fuel position?