190204c Electronic Fuel System Diagnosis Flashcards
What must you do before removing rocker assemblies ?
Back off the adjustment screw.
If you don’t have the tooling to install an injector what should you use ?
Not hitting the solenoid or the follower carefully tap the injector into position with a dead blow hammer
What must be removed to gain access to the injectors ?
Rocker housing/valve cover
Engine brake head &
Rocker levers.
Before replacing an EUI, you should clean the injector tube paying particular attention to the?
Combustion seal seat
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?
False. Injector should be pushed down into the cylinder head until it bottoms
Injector O-rings should never be lubricated with engine oil before installing. True or false?
False. Injector O-rings should always be lubricated with engine oil before installing
The 2 basic path for diagnosis/ troubleshooting are
Symptom based and fault code based
When preforming harness repair what percautions should be followed?
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
Protect the ECM from excessive voltage and surges how?
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
When diagnostic a issue on equipment best to talk to operator, what questions would u ask them?
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
List 4 steps that must be performed to complete the installation of an EUI
- 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
When replacing the ECP, failure to purge the fuel supply passages will result in?
Engine oil dilution
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?
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.
Before attempting to remove an EUP, you must?
Remove the high pressure fuel line, disconnect the solenoid wiring connections, and clean around the pump
Before installing an EUP, you should?
Inspect the roller tappet for wear and damage
When replacing an EUP, there is no specific procedure for tightening the mounting bolts. True of false?
False. Pump moin ting bolts should be tightened evenly to pull the pump into the block and then torque to specifications
After pump replacement, EUP heat shields do not need to be replaced if the fuel system has an ECM cooling plate. True of false?
False. The heat shields should be replaced to protect electronic components
Before the replacement procedure for an EUP is completed, you will need to?
Program the calibration code
Physical damage to a harness can allow moisture to enter the wiring causing corrosion. The corrosion will eventually lead to what?
High resistance and opens on the electrical circuit.
True or false
Some engine fault codes will only appear with the engine running?
True
Most manufacturers use a diagnostic switch to activate what?
Flashing fault code lamps
Information that may be included with PC based diagnostic tools
Precautions Component location Detailed fault code information Troubleshooting charts Repair procedures
True or false
It is acceptable to skip steps in a manufacturers trouble shooting procedure?
False
What would you be looking for while performing checks on a wiring harness?
Check harness resistance values to determine electrical opens, shorts and ground faults
After a component has been identified as a defective unit, what should be preformed next?
Test the component to ensure that it is actually faulty
After all the repairs/replacements have been done on a fuel injection system. and all the codes have been cleared, you should then?
Disconnect all the diagnostic equipment, replace all machine protective panels and Road test the vehicle
While the engine is running, you should not touch?
Electronic injector harness or pump connections - there is a high voltage present which can cause a serious electrical shock and personal injury
Failure to drain the fuel passage before removing an injector can cause?
Hydraulic lock which can result is failures such an bent connecting rods.
When using air pressure to drain fuel passages, you should never?
Use air pressure that exceeds the normal transfer pressure or fuel system damage may occur
What precautions should be observed when replacing components on any electronically controlled fuel system?
- 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
When performing a visual inspection means what?
Use your phyical senses
Sight, feel, smell, and hearing
The best repair a broken wiring harness in an electronic fuel injection system is what
Complete replacement
If a new wiring harness is not available and you must repair a broken conductor it is acceptable to what?
Make a well insulated, resistance free soldered splice
True or false. When you were accessing fault codes using a personal computer, the engine must always be running
False
When using a PC with diagnostic software you can access information relating to
Fault codes, troubleshooting trees, electronic component location and time fault code occurrence.
Following a logical troubleshooting process decreases the time required to locate a fault. True or false
True
When testing a replacing components in an electronic control system, you should
Ensure the key switch is off before disconnecting any circuit
If a special puller is not available, an EUI can be safely removed using what
A heel bar
When replacing MEUI, before you remove the injector from the cylinder head you should
Check for debris around the base of the injector
List five stages of the HEUI fuel injector process?
Pre-injection pilot injection delay injection main injection end of injection
