Fuel System Diagnosis And Repair

Question 1

The drain system is checked for —– pressure or —– .

Excess pressure or flow in the drain system is a indication of a failed —–,—–, or a —– drain line.

A drain test is preformed ——- on each item to determine the failed component .

Answer 1

1) excess / flow
2) injector,pressure relief valve,restricted
3) individually

Question 2

A buzz test refers to KOEO —– solenoid test when a sound from —– is heard

When signal wires are spliced into a harness, use wire with —— insulation. Because of the low current and voltage levels you should —— the splices.

Answer 2

1) injector, injector

2) high temp , solder

Question 3

The EUI plunger is a —— member and is spring loaded into its —– position. The plunger is actuated by —– profile.

EUI injectors have a injector camshaft mounted on the —— or ——.
The injector train is actuated by cam —– , the EUI plunger is driven through its stroke.

EUI plunger stroke does not vary regardless of how the engine is being —–.

Answer 3

1 Reciprocating , retracted , cam
2 cylinder block , over head , profile
3 fueled

Question 4

To check for water in the fuel tanks first allow the fuel to —— and then insert a —— rod coated with —– detection —— until the rod touches the bottom.

Fuel sending units consist of a —– ,—– and —– resistor.

Answer 4

1 settle , aluminum , water , paste

2 arm , float , variable

Question 5

EUI is typically provided fuel by means of a —— integral with the cylinder head. Excess fuel is used to —— and ——.

The —– is cam actuated , integral pumping , metering and atomizing device that is controlled by the —–.

The pumping element of a EUI consist of a —– and a —–.

Answer 5

1 manifold , lubricate , cool
2 EUI , ECM
3 plunger , barrel

Question 6

When performing cylinder cut out test on EUI after a cylinder has been cut out the EUI should increase their ——-.

The common rail system usually has high pressure pump and a low pressure pump.

High pressure common rails are tested for supply pump —— and —— , high pump pressure , and sometimes ——.

Answer 6

1 pulse width

2 pressure , flow , drain system pressure

Question 7

Low supply pump pressure / flow can be caused by —— , a worn —— or insufficient fuel in the tank.

Low pressure from the high pressure pump can be cause by low supply pump pressure or —– , a weak —— pump a faulty fuel pressure control valve or pressure relief valve.

Answer 7

1 fuel filters , pump

2 flow , high pressure

Question 8

If the accelerator pedal position sensor or —— sensor is adjusted it is normally adjusted to approx —— volts at idle.

HEUI stands for ———.

EUI stands for ———.

EUI system consist of a —– side and a charge side with fuel movement provided by a positive displacement —– type pump.

Answer 8

1 throttle position
2 hydraulic electric unit injector
3 electronic unit injector
4 suction , gear

Question 9

The —— sensor connects to the accelerator pedal and sends and input to the ECM.

The ECM uses the throttle valve to aid in —— flow.

Answer 9

1 accelerator pedal position

2 EGR

Question 10

The low pressure side of the fuel system will have a —— fitting or —– valve .

To remove high pressure fuel lines
1 remove ——-
2 disconnect ——- lines then cap off —– and injection lines
3 disconnect fuel lines at ——–.

Answer 10

1 restrictor , regulating

2 low pressure lines , injection , injectors , injection pump

Question 11

Fuel heaters are electrical ________ heaters and can be checked with an _________ or __________. The ECM typically controls these based upon _______.

If fuel heaters fail to shut off they can cause __________ concerns__________ because of fuel _________ .

Some systems use fuel coolers which are _____ to_______ which usually get contaminated by _______ .

Answer 11

1 resistance , ohm meter , amp meter , temperature
2 low power , overheating
3 fuel , air , mud

Question 12

ECM cooling plates are mounted under the ECM and have ________ flowing through them .

Dry fuel filter installation is recommended by most OEMS to prevent _______ from entering.

Normal fuel filter restriction max is _______ psi. Low _____ and low _____ pressure are common fuel filter restriction concerns.

Answer 12

1 fuel
2 dirt
3) 5 , power , boost

Question 13

One method of checking for air in the fuel is to install a clear piece of hose or liquid eye in the fuel ________ line. Another is to remove the return line and submerge it into a ________.

Air in the fuel system can cause low ________ and surging ________, and ____________ .

Answer 13

1 supply , fuel

2 power , rpm , hard starting

Question 14

Steps to priming a fuel system
1 locate a ________ point in the system on inline injection pumps this will usually be at the exit of the ___________________ .

2 If the system is equipped with a hand primer actuate it until ________ cease to exit . If it does not have one install one upstream from the _________ filter.

3 Then crank for ______ second segments with ________ mins between high pressure circuits will self prime when ________ systems are primed.

Answer 14

1 bleed , charging gallery
2 air bubble , secondary
3 30 , 2 , sub

Question 15

Low fuel supply pressure Ina a common cause of _______ and low turbocharger ________ pressure.

Insufficient fuel flow can result in low power and fuel ______. Fuel pump failure on Diesel engines can be associated with ________.

Fuel ware separators should be drained when ________ .

Products that remove water should never be used because they tend to for water through the ________ system.

Answer 15

1 low power , boost
2 starvation , fuel starvation
3 every service
4 injection

Question 16

Fuel supply systems have a ______ pressure sipe and a ______ pressure side.

The ________ pressure side will have a ______ fitting or regulating valve to control the pressure these valves can stick _____ or _____.

When a fuel pressure valve sticks closed fuel pressure will be _____ this can cause ________ of the fuel and cause component damage

Answer 16

1 low , high
2 low , restrictor , open , closed
3 lower
4 high , overheating

Question 17

Some EUI’s require setting of the plunger ______ this adjustment is preformed by adjusting a _______ on the ______ .

EUI height adjustment methods require _____ , _____, and ______ adjustment gauges.

Answer 17

1 height , screw , rocker arm

2 torque wrench , dial indicator , height

Question 18

When a transfer pump is used there is a divide in the fuel system there is a _______ side and _______ side

A primary filter is usually located on the _______ side and the secondary filter is on the ________ side.

Many diesel fuel management systems pump greater quantities of fuel than is required .

Answer 18

1 suction , charge

2 suction , charge

Question 19

Excess fuel that is pumped through the fuel system is returned to the fuel system is returned to the tank and used to ______ and ______ high pressure injection components.

Fuel transfers ______ from the injection devices to the ______ which provides it with the role of a heat exchanger.

A plugged fuel tank vent will create a restriction in the suction ________ that the transfer pump can’t overcome.

Answer 19

1 cool , lubricate
2 heat , fuel tank
3 hose or side?

Question 20

Engine protection systems are designed to _______ horsepower and _______. When the ECM recognizes that the engine is overheating over speeding or has low ______ pressure.

Auto start/ restart systems are designed to reduce ______ time.

Answer 20

1 lower , torque , oil

2 idle

Question 21

Fuel sending units can be diagnosis with a ________ in ______ mode.

Pick up tubes draw fuel slightly above the ______ of the fuel tank to avoid picking up ______ and ______. Pick up tubes usually fail because of metal fatigue cracks at the ______.

Low fuel supply pressure is a common cause of low ______/ low turbocharger _______ pressure.

Answer 21

1 DMM , resistance
2 bottom , sediments , water
3 power , boost