190204c Electronic Fuel System Diagnosis

Question 0

What must you do before removing rocker assemblies ?

Answer 0

Back off the adjustment screw.

Question 1

If you don’t have the tooling to install an injector what should you use ?

Answer 1

Not hitting the solenoid or the follower carefully tap the injector into position with a dead blow hammer

Question 2

What must be removed to gain access to the injectors ?

Answer 2

Rocker housing/valve cover
Engine brake head &
Rocker levers.

Question 4

Before replacing an EUI, you should clean the injector tube paying particular attention to the?

Answer 4

Combustion seal seat

Question 5

When replacing an EUI, it is an acceptable practice to pull the injector into the head using the hold down clamp assembly. True or false?

Answer 5

False. Injector should be pushed down into the cylinder head until it bottoms

Question 6

Injector O-rings should never be lubricated with engine oil before installing. True or false?

Answer 6

False. Injector O-rings should always be lubricated with engine oil before installing

Question 7

The 2 basic path for diagnosis/ troubleshooting are

Answer 7

Symptom based and fault code based

Question 8

When preforming harness repair what percautions should be followed?

Answer 8

Connectons are tight and clean
Protect harness from abrasion moisture and oil.
Best way to repair damage harness is replace complete harness
Ensure all solder splices are insulated for contamination

Question 9

Protect the ECM from excessive voltage and surges how?

Answer 9

Unplug Ecu when welding on equipment
-Don’t use a fast charger to start engine
-Never disconnect the battery with engine running
Never open electrical connections when the electronic control system is operational

Question 10

When diagnostic a issue on equipment best to talk to operator, what questions would u ask them?

Answer 10

What job were you doing when it happen?
•has another shop done anything to it repair or service?
•did electroincs or dash turn on and off.
•did it happen at a specific engine RPM

Question 11

List 4 steps that must be performed to complete the installation of an EUI

Answer 11

• install the rocker shafts and related components
• adjust the valves and injectors
• install and adjust engine brakes
• install rocker covers
• bleed the fuel system before starting the engine
• test engine operation to confirm repairs have correct the problem

Question 12

When replacing the ECP, failure to purge the fuel supply passages will result in?

Answer 12

Engine oil dilution

Question 13

When replacing an EUP, it is an acceptable practice to remove both of the mounting bolts and let spring tension eject the pump from the cylinder block. True or false?

Answer 13

False. Remove one mounting bolt and loosen the other one. When the pump has moved away from the cylinder block, you can remove the other bolt.

Question 14

Before attempting to remove an EUP, you must?

Answer 14

Remove the high pressure fuel line, disconnect the solenoid wiring connections, and clean around the pump

Question 15

Before installing an EUP, you should?

Answer 15

Inspect the roller tappet for wear and damage

Question 16

When replacing an EUP, there is no specific procedure for tightening the mounting bolts. True of false?

Answer 16

False. Pump moin ting bolts should be tightened evenly to pull the pump into the block and then torque to specifications

Question 17

After pump replacement, EUP heat shields do not need to be replaced if the fuel system has an ECM cooling plate. True of false?

Answer 17

False. The heat shields should be replaced to protect electronic components

Question 18

Before the replacement procedure for an EUP is completed, you will need to?

Answer 18

Program the calibration code

Question 19

Physical damage to a harness can allow moisture to enter the wiring causing corrosion. The corrosion will eventually lead to what?

Answer 19

High resistance and opens on the electrical circuit.

Question 20

True or false

Some engine fault codes will only appear with the engine running?

Answer 20

True

Question 21

Most manufacturers use a diagnostic switch to activate what?

Answer 21

Flashing fault code lamps

Question 22

Information that may be included with PC based diagnostic tools

Answer 22

Precautions 
Component location 
Detailed fault code information 
Troubleshooting charts
Repair procedures

Question 23

True or false

It is acceptable to skip steps in a manufacturers trouble shooting procedure?

Answer 23

False

Question 24

What would you be looking for while performing checks on a wiring harness?

Answer 24

Check harness resistance values to determine electrical opens, shorts and ground faults

Question 25

After a component has been identified as a defective unit, what should be preformed next?

Answer 25

Test the component to ensure that it is actually faulty

Question 26

After all the repairs/replacements have been done on a fuel injection system. and all the codes have been cleared, you should then?

Answer 26

Disconnect all the diagnostic equipment, replace all machine protective panels and Road test the vehicle

Question 27

While the engine is running, you should not touch?

Answer 27

Electronic injector harness or pump connections - there is a high voltage present which can cause a serious electrical shock and personal injury

Question 28

Failure to drain the fuel passage before removing an injector can cause?

Answer 28

Hydraulic lock which can result is failures such an bent connecting rods.

Question 29

When using air pressure to drain fuel passages, you should never?

Answer 29

Use air pressure that exceeds the normal transfer pressure or fuel system damage may occur

Question 30

What precautions should be observed when replacing components on any electronically controlled fuel system?

Answer 30

• Number disconnected battery while the engine is running
• Do not open electrical connectors with electronic control systems operational
• Keep components in their original location
• Make sure that injector wiring or in his connections are clean and tight
• Protect the injector and pronghorn harnesses from abrasion and pinch points
• Keep electronic injector and pump connections free of moisture and oil contamination
• Always use manufacturers recommended procedures and specifications

Question 31

When performing a visual inspection means what?

Answer 31

Use your phyical senses

Sight, feel, smell, and hearing

Question 32

The best repair a broken wiring harness in an electronic fuel injection system is what

Answer 32

Complete replacement

Question 33

If a new wiring harness is not available and you must repair a broken conductor it is acceptable to what?

Answer 33

Make a well insulated, resistance free soldered splice

Question 34

True or false. When you were accessing fault codes using a personal computer, the engine must always be running

Answer 34

False

Question 35

When using a PC with diagnostic software you can access information relating to

Answer 35

Fault codes, troubleshooting trees, electronic component location and time fault code occurrence.

Question 36

Following a logical troubleshooting process decreases the time required to locate a fault. True or false

Answer 36

True

Question 37

When testing a replacing components in an electronic control system, you should

Answer 37

Ensure the key switch is off before disconnecting any circuit

Question 38

If a special puller is not available, an EUI can be safely removed using what

Answer 38

A heel bar

Question 39

When replacing MEUI, before you remove the injector from the cylinder head you should

Answer 39

Check for debris around the base of the injector

Question 40

List five stages of the HEUI fuel injector process?

Answer 40

Pre-injection
pilot injection
delay  injection
main injection
end of injection