Fuel Systems and Components
. In a GDI system (gasoline direct injection) the injector sprays fuel into the
Combustion chamber
2. Which of the following is not a PCM output?
solenoids lights (indicator)
thermostats relays
Thermostats
Technician A uses the snapshot function of his scan tool to record serial data during a road test that can be transferred and displayed on a PC. Technician B uses the snapshot feature of his scan tool to record the sensor data and conditions leading up to the vehicle setting a DTC. Who is correct?
A only both A and B
B only neither A nor B
A only
Which of the following should be checked before proceeding with specific fuel injection and electronic control testing?
vaccum lines
pcv system
Engine Coolant level
all of the above
vaccum lines
pcv system
Engine Coolant level
Reach, heat range, and air gap are all characteristics that affect the performance of which ignition system component?
Spark plugs
Which of the following problems would NOT cause a oxygen sensor to appear bad?
leaking fuel injector leaking EGR valve
leaking intake manifold gasket
leaking muffler to tailpipe gasket
leaking muffler to tailpipe gasket
Data collected by system sensors is stored in _____ memory.
Ram ( Random Access Memory)
Two technicians are discussing IAT sensors (intake air temperature). Technician A says the IAT sensor is an integral part of the mass airflow sensor (MAF). Technician B says the IAT is a discrete sensor located in the intake air passages or air cleaner assembly. Who is correct?
A only both A and B
B only neither A nor B
Both A and B
A no-start condition on an EI system is being discussed. Technician A says to use a test spark plug to determine whether the problem is in the ignition system. Technician B says that if a noid light is connected to the injector harness and it pulses while the engine is cranked, the triggering unit for the primary ignition circuit should be okay. Who is correct?
Who is Both A and B
The magnetic field surrounding the pickup coil in a magnetic pulse generator moves when the ______.
reluctor tooth begins to move away from the pickup coil
A camshaft position sensor provides the PCM with data needed to control _____.
fuel injector timing
ignition coil timing (COP ignition)
variable valve timing
4. To read flash codes on an OBD I Chrysler-built vehicle ______.
connect terminals A and B on the DLC with a jumper wire
turn the rotary switch on the PCM counter clockwise 3 clicks
connect the E1 and TE1 terminals on the DLC
turn the ignition key on and off three times in five seconds, ending in on
turn the ignition key on and off three times in five seconds, ending in on
A technician is rebuilding an engine and notices that one tooth is missing from the crank sensor pulse ring. Technician A says the pulse ring is broken and will have to be replaced. Technician B says that missing tooth identifies when cylinder #1 is at TDC and that the missing tooth is normal. Who is correct?
who is Tech B
A vehicle towed into the shop with a “cranks but doesn’t start” problem. A quick check under the hood reveals that the spark plugs are not firing and the injectors are not receiving a pulse from the PCM. The technician notices that the MIL light does not come on when the key is turned to the run position. What would you do next?
Check the PCM’s fuses, power wires, and ground wires
Replace the PCM
Check the main power relay in the power distribution center
Check for codes with a scan tool
Check the PCM’s fuses, power wires, and ground wires
Which of the following is NOT a type of engine position sensor?
Hall-effect photoelectric [optical]
magnetic pulse generator piezoresistive
piezoresistive
A plugged fuel filter will cause ______.
High speed surge
hesitation on acceleration
loss of power at high speed ( engine cut out)
. A conventional oxygen sensor needs to be heated to ________ degrees Fahrenheit before it can produce a usable signal.
750 degrees
Ignition timing is being discussed. Technician A says when the engine idle speed moves away from the desired idle speed, the PCM will adjust the timing to stabilize the engine speed. Technician B says when a knock is detected, the PCM retards the timing in fixed steps until the knock disappears. Who is correct?
Who is Both Technicians
A vehicle with a DTC for an engine coolant temperature out of range code is being tested.
The serial data stream shows the coolant temperature to be 198 degrees Fahrenheit. When the technician tests the resistance between the ETC terminals, he finds infinite resistance. The specifications call for 20 to 40 ohms at 200 degrees Fahrenheit. After the ECT is replaced and the code is erased, the system runs normally and the code and MIL illumination do not reoccur. How is this possible?
There was excessive air in the cooling system; when the ECT sensor was removed, the trapped air bled out
The ETC code was set by a loose connection where the harness meets the ECT terminals; disconnecting and reconnecting the plug essentially fixed the problem
The problem is an intermittent electrical fault; it will eventually reoccur
When the ECT failed, the PCM substituted a nominal ECT value that allowed the engine to run in limp home mode; the substituted value was displayed by the scan tool
When the ECT failed, the PCM substituted a nominal ECT value that allowed the engine to run in limp home mode; the substituted value was displayed by the scan tool
An ohmmeter connected to the leads of a pickup coil in a DI ignition system reads 14 ohms of resistance. The reading indicates that the pickup coil ______.
What is Shorted
If twenty inches of vacuum is applied to the fuel pressure regulator while the fuel pump is running, the fuel pressure should _____.
Increase
An air/fuel ratio sensor is different from an oxygen sensor in that ______.
the signal output is a varying current (amps)
as the mixture becomes leaner, its output signal increases
the output responds to minor changes in air/fuel mixture, not just rich/lean conditions
Resistor-type spark plugs are being discussed. Technician A says the resistor increases the plug firing voltage. Technician B says the resistor helps reduce radio frequency interference [RFI], which can interfere with, or damage, radios, computers, and other electronic accessories, such as GPS systems. Who is correct?
Who is Both Technicians
A rich air/fuel mixture is being discussed. Technician A says oxygen content in the exhaust will be high.
Technician B says the O2 sensor voltage will be high. Who is correct?
Who is Tech B
What could a leak in the fuel pressure regulator or the fuel pump check valve that allows the fuel pressure to slowly bleed down after engine shut down cause?
What is Hard starting