2003 FORD MUSTANG vacuum

8. Disconnect the vacuum hose.
9. Disconnect the fuel supply spring lock coupler. For additional information, refer to
Section 310 -
00 .
10. Disconnect the accelerator controls. zDisconnect the accelerator cable.
z If equipped, disconnect the speed control cable. 11. Remove the accelerator cable bracket bolts. Klj . 2 ba
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12. Remove the throttle body and spacer assembly.
13. Release the clip and position the accelerator cable bracket and the cables aside.
14. Disconnect the electrical connectors from the fuel pulse damper, EGR vacuum regulator
solenoid, supercharger bypass vacuum solenoid, and the differential pressure feedback EGR
system.
15. Disconnect the vacuum hoses from the differential pressure feedback EGR system. Klj . 3 ba
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16. Disconnect the vacuum hoses from the supercharger bypass vacuum solenoid, and the
actuator.
17. Disconnect the vacuum hoses from the fuel pulse damper and the EGR vacuum regulator solenoid.
18. Disconnect the vacuum hose from the EGR valve.
19. Disconnect the vacuum hoses at the back of the supercharger and position the vacuum harness aside. Klj . 4 ba
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20. Remove the vacuum accessory bracket mounting nut.
21. Remove the mounting bolts, and the vacuum accessory bracket.
22. Disconnect the exhaust manifold to EGR valve tube.
23. Disconnect the barometric pressure (BARO) sensor electrical connector. Klj . 5 ba
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z
prevents hydrocarbon emissions from reaching the atmosphere.
z stores fuel vapors in the evaporative emission (EVAP) canister that are generated during
vehicle operation or hot soak, or vehicle refueling, until they can be consumed by the engine.
z routes the stored fuel vapors to the engine during engine operation.
z is controlled by the powertrain control module (PCM) which uses various sensor inputs to
calculate the desired amount of purge flow. The PCM regulates the purge flow, induced by the
application of intake manifold vacuum, by varying the duty cycle applied to the EVAP canister
purge valve.
z has an evaporative emission test port for test purposes.
The fuel vapors are routed:
zfrom the fuel tank through the fuel vapor control valve and fuel vapor vent valve.
z to the EVAP canister through a vapor line.
z to the engine when the EVAP canister purge valve is opened by the PCM.
The fuel tank pressure (FTP) sensor:
zmonitors the pressure levels in the fuel tank.
z communicates the pressure reading to the PCM during the OBDII leak test.
z is located in- line above the fuel tank and is serviced as part of the fuel vapor control valve tube
assembly.
The evaporative emission canister:
zis located in the left rear quarter panel.
z contains activated carbon.
z stores fuel vapor.
The fuel tank filler cap:
zrelieves system pressure above 14 kPa (56.21 inches H
2 O).
z relieves system vacuum below 3.8 kPa (15.26 inches H
2 O).
The canister vent solenoid: zis normally open.
z seals the EVAP system for the inspection and maintenance (I/M 240) test and OBDII leak and
pressure tests.
z is mounted to the evaporative emission canister.
z is repaired as a separate item.
The evaporative emission (EVAP) canister purge valve:
zis normally closed.
z regulates purging of the EVAP canister.
z is controlled by the PCM. Klj . 2 ba
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z
is located in the right front inner fender well.
The fuel vapor control valve tube assembly:
zconsists of the fuel vapor control valve, fuel vapor vent valve and an in- line fuel tank pressure
sensor.
z prevents suspended liquid fuel from being drawn into the evaporative emission canister along
with the fuel vapors.
z returns the liquid to the fuel tank.
z includes a fresh air transfer tube routing fresh air between the canister vent solenoid hose and
the fuel tank filler pipe assembly.
z requires two grommets to seal the fuel vapor control valve and fuel vapor vent valve to the fuel
tank.
The evaporative emission (EVAP) system monitor:
zis a self- test strategy within the PCM, which tests the integrity of the EVAP system.
z monitors the EVAP system for leaks.
z monitors electronic EVAP components for irrationally high or low voltages.
z monitors for correct EVAP system operation.
z utilizes intake manifold vacuum to test the EVAP system and involves several stages.
The evaporative emission (EVAP) test port:
zis used to connect the Evaporative Emission System Leak Tester to the EVAP system.
z is located on the EVAP canister purge outlet tube near the EVAP canister purge valve. Klj . 3 ba
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Principles of Operation
Evaporative Emission (EVAP) Canister Purge Valve
The EVAP canister purge valve is controlled by the powertrain control module (PCM). The EVAP
canister purge valve controls the flow of fuel vapors from the EVAP canister to the engine intake
manifold during various engine operating modes. The EVAP canister purge valve is normally closed.
Evaporative Emission (EVAP) Canister
Fuel vapors from the fuel tank are stored in the EVAP canister. When the engine is running, the vapors
are purged from the EVAP canister for combustion.
Canister Vent Solenoid
During the Evaporative Emission (EVAP) System Test Monitor, Evaporative Emissions Repair
Verification Drive Cycle, and the Evaporative Emission System Leak Test, the canister vent solenoid is
closed to allow a vacuum to be drawn on the fuel tank at a specific level. The canister vent solenoid is
normally open.
Fuel Tank Pressure (FTP) Sensor
The fuel tank pressure sensor is used to measure the fuel tank pressure during the Evaporative
Emissions Monitor Test. The fuel tank pressure sensor is mounted in the fuel vapor control valve tube
as it crosses over the fuel tank.
Fuel Vapor Control Valve
The fuel vapor control valve is normally between the EVAP canister and the fuel vapor vent valve. Its
function is to prevent the flow of liquid fuel into the EVAP canister or up to the canister purge valve
during refueling, and to prevent the collection of liquid fuel in the fuel vapor hoses by overfilling the fuel
tank.
Fuel Vapor Vent Valve (FVV) Assembly
The fuel vapor vent valve (FVV) assembly is mounted on the top of the fuel tank. It is used to control
the flow of fuel vapors entering the EVAP system. The head portion of the assembly prevents the fuel
tank from overfilling during refueling. The assembly also has a spring float, which prevents liquid fuel
from entering the vapor delivery system under severe handling or vehicle rollover conditions. In the
upright position, the open bottom of the float will lift and shut off the orifice. Under severe handling
conditions, the spring will push the float closed when angles allow liquid fuel to reach the orifice. In a
rollover condition, the weight of the open bottom float and spring pressure will close the orifice.
Fuel Filler Pipe Check Valve
The fuel filler pipe check valve is an intricate part of the fuel filler pipe. It is intended to prevent liquid
fuel from re-entering the fuel filler pipe from the fuel tank on refueling or roll over conditions.
Fuel Filler Cap
The fuel filler cap is used to prevent fuel spill and to close the EVAP system to the atmosphere.
Evaporative Emission System Monitor
When a fault occurs, the EVAP system monitor is reset to NO and a diagnostic trouble code (DTC) is
set in the PCM memory. After the DTC is repaired, the vehicle drive cycle must be completed to reset
the monitor in preparation for inspection and maintenance testing. EVAP Emission System Leak Test Klj . 2 ba
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To start the testing, conditions of stable purging and vehicle speed must be satisfied. During the first
stage, the canister vent solenoid is closed, while the EVAP canister purge valve remains open,
applying and building vacuum in the system as indicated by the FTP sensor. This phase checks for
major leaks in the EVAP system.
In the second stage, the EVAP canister purge valve closes and the system looks for minimal decay
rate in the EVAP vacuum, indicating the absence of any small EVAP system leaks.
The last stage is entered only if stage two of the leak test has failed and checks whether the failed test
was due to excess vapor generation. It monitors fuel vapor generation rate. Initially, the canister vent
solenoid is opened to equalize EVAP system pressure to atmosphere. Then the canister vent solenoid
is closed, allowing pressure to build if vapor generation is present in sufficient quantity. If the rate of
generation is found to be too high, the EVAP running loss system leak test is aborted. If not, then a
small leak is diagnosed.
On-
Board Refueling Vapor Recovery (ORVR) Evaporative Emission (EVAP) System
The basic elements forming the ORVR system are as follows:
zThe fuel filler pipe forms a seal to prevent vapors from escaping the fuel tank while liquid is
entering the fuel tank. Liquid in the one inch diameter tube blocks vapors from rushing back up
the fuel filler pipe.
z A fuel vapor control valve controls the flow of vapors out of the fuel tank. The valve closes when
the liquid level reaches a height associated with fuel tank usable capacity. The valve
accomplishes the following:
„limits the total amount of fuel that can be dispensed into the fuel tank
„ prevents liquid gasoline from exiting the fuel tank when submerged (as well as when
tipped well beyond a horizontal plane as part of the vehicle rollover protection in road
accidents)
„ minimizes vapor flow resistance during anticipated refueling conditions
z Fuel vapor tubing connects the fuel vapor control valve to the EVAP canister. This routes the
fuel tank vapors, displaced by the incoming liquid, to the EVAP canister.
z A check valve in the fuel filling system prevents liquid from rushing back up the fuel filler pipe
during the liquid flow variations associated with the filler nozzle shut- off.
Between refueling events, the EVAP canister is purged with fresh air so that it may be used again to
store vapors accumulated during engine soaks or subsequent refueling events. The vapors drawn off
of the carbon in the EVAP canister are consumed by the engine.
Inspection and Verification 1. Verify the customer concern is with the evaporative emission (EVAP) system.
2. Visually inspect for the following obvious signs of mechanical damage.
Visual Inspection Chart Mechanical
z
Fuel filler cap
z EVAP test port
z EVAP canister or canister vent solenoid Klj . 3 ba
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