15. Figure 16-2 A three-piece filler tube assembly.
16. Figure 16-3 A view of a typical filler tube with the fuel tank removed. Notice the ground strap used to help prevent the buildup of static electricity as the fuel flows into the plastic tank. The check ball looks exactly like a ping-pong ball.
17. Figure 16-4 Vehicles equipped with on-board refueling vapor recovery usually have a reduced-size fill tube.
18. Figure 16-5 The fuel pickup tube is part of the fuel sender and pump assembly.
19. Figure 16-6 On some vehicles equipped with an air flow sensor, a switch is used to energize the fuel pump. In the event of a collision, the switch opens and the fuel flow stops.
20. Figure 16-7 Ford uses an inertia switch to turn off the electric fuel pump in an accident.
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27. Figure 16-8 Fuel lines are routed along the frame or body and secured with clips.
28. Figure 16-9 Some Ford metal line connections use spring-locks and O-rings.
29. Figure 16-10 Ford spring-lock connectors require a special tool for disassembly.
30. Figure 16-11 Typical quick-connect service steps.
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44. Figure 16-12 A roller cell-type electric fuel pump.
45. Figure 16-13 The pumping action of an impeller or roller vane pump.
46. Figure 16-14 An exploded view of a gerotor electric fuel pump. The impeller draws fuel from the tank through the sock and into the gerotor pump area. The impeller is also used to expel any vapors that could be in the fuel.
47. Figure 16-15 A cutaway view of a typical two-stage turbine electric fuel pump.
48. Figure 16-16 A typical fuel-pump module assembly, which includes the pickup strainer, fuel pump, as well as the fuel-pressure sensor and fuel-level sensing unit.
49. Figure 16-17 A schematic showing that an inertia switch is connected in series between the fuel-pump relay and the fuel pump.
50. Figure 16-18 A typical fuel pulsator used mostly with roller vane-type pumps to help even out the pulsation in pressure that can cause noise.
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54. Figure 16-19 Inline fuel filters are usually attached to the fuel line with screw clamps or threaded connections. The fuel filter must be installed in the proper direction or a restricted fuel flow can result.
55. Figure 16-19 (continued) Inline fuel filters are usually attached to the fuel line with screw clamps or threaded connections. The fuel filter must be installed in the proper direction or a restricted fuel flow can result.
56. Figure 16-20 Many fuel-pump modules contain a nonreplaceable fuel filter.
57. Figure 16-21 The final filter, also called a filter basket, is the last filter in the fuel system.
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60. (Continued) 90-110 Central port fuel injection (GM) 55-64 70-90 Port fuel-injection systems 35-45 50-70 High-pressure TBI units 25-35 18-20 Low-pressure TBI units 9-13 Maximum Pump Pressure (psi) Normal Operating Pressure (psi)
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77. Figure 16-22 (a) A funnel helps in hearing if the electric fuel pump inside the gas tank is working. (b) If the pump is not running, check the wiring and current flow before going through the process of dropping the fuel tank to remove the pump. A
78. Figure 16-22 (continued) (a) A funnel helps in hearing if the electric fuel pump inside the gas tank is working. (b) If the pump is not running, check the wiring and current flow before going through the process of dropping the fuel tank to remove the pump. B
79. Figure 16-23 Typical fuel pressure test Schrader valve.
80. Figure 16-24 A fuel-pressure gauge connected to the fuel pressure tap (Schrader valve) on a port-injected V-6 engine.
81. Figure 16-25 The fuel system should hold pressure if the system is leak free.
82. Figure 16-26 Most OBD-I General Motors fuel-injected vehicles are equipped with a fuel-pump test connector. The operation of the fuel pump can be checked by connecting a 12-volt test light to the positive (1) terminal of the battery and the point of the test light to the test connector. Turn the ignition to on (engine off). The light should either go out or come on for 2 seconds. This is a simple test to see if the computer can control the fuel-pump relay.
83. Figure 16-27 If the vacuum hose is removed from the fuel-pressure regulator when the engine is running, the fuel pressure should increase. If it does not increase, then the fuel pump is not capable of supplying adequate pressure or the fuel-pressure regulator is defective. If gasoline is visible in the vacuum hose, the regulator is leaking and should be replaced.
84. Figure 16-28 Fuel should be heard returning to the fuel tank at the fuel return line if the fuel pump and fuel-pressure regulator are functioning correctly.
85. Figure 16-29 A fuel-pressure reading does not confirm that there is enough fuel volume for the engine to operate correctly.
86. Figure 16-30 Measuring the volume of fuel flowing through the fuel-pressure regulator may not show the true volume capacity of the fuel pump.
87. Figure 16-31 A non-restricted (wide-open) fuel volume test using a fuel volume tester without the restriction of other components in the fuel system, such as the regulator.
88. Figure 16-32 Removing the bed from a pickup truck makes gaining access to the fuel pump a lot easier.
93. Figure 16-33 The hookup to test the current draw of the fuel pump on a General Motors vehicle that is equipped with a fuel-pump test lead (prime connector).
94. Figure 16-34 To test the current draw of a fuel pump on a Ford vehicle, connect the meter leads at either the relay or the inertia switch.
95. Figure 16-35 Hookup for testing fuel-pump current draw on any vehicle equipped with a fuel-pump relay.
106. Figure 16-37 Charcoal canister as mounted under the hood (Jeep). Not all charcoal canisters are this accessible; in fact, most are hidden under the hood or in other locations on the vehicle.
107. Figure 16-38 The evaporative emission control system includes all of the lines, hoses, and valves, plus the charcoal canister.
108. Figure 16-39 A typical evaporative emission control system. Note that when the computer turns on the canister purge solenoid valve, manifold vacuum draws any stored vapors from the canister into the engine. Manifold vacuum also is applied to the pressure control valve and when this valve opens, fumes from the fuel tank are drawn into the charcoal canister and eventually into the engine. When the solenoid valve is turned off (or the engine stops and there is no manifold vacuum), the pressure control valve is spring loaded shut to keep vapors inside the fuel tank from escaping to the atmosphere.
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115. Figure 16-40 A typical OBD-II EVAP system which uses fuel-tank pressure and purge flow sensors to detect leaks and measure purge flow. The purge flow sensor is similar to a mass air flow sensor and measures the amount of flow into the engine.
116. Figure 16-41 The vapor management valve (VMV) and the canister purge valve (CPV) are both PCM controlled and control and check for proper flow through the evaporative control system. The fuel tank pressure (FTP) sensor monitors vapor pressure inside the fuel tank.
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118. Figure 16-42 A typical purge flow tester connected in series between the intake manifold (or control solenoid) and the charcoal canister. Most working systems should be capable of flowing at least 1 L/min. Some vehicles must be test driven because their computers only purge after a certain road speed has been achieved.
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122. Figure 16-43 Some vehicles will display a message if an evaporative control system leak is detected that could be the result of a loose gas cap.
123. Figure 16-44 (a) A typical EVAP diagnostic tester. (b) A smoke test shows a leaking gas cap. A A
124. Figure 16-44 (continued) (a) A typical EVAP diagnostic tester. (b) A smoke test shows a leaking gas cap. B
125. Figure 16-45 An emission tester that uses nitrogen to pressurize the fuel system.
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133. Figure 16-46 Typical evaporative system showing the valves and the normal position.
134. Figure 16-47 An assortment of gas caps used during testing of the EVAP system.
135. Figure 16-48 The fuel level must be above 15% and below 85% before the EVAP monitor will run on most vehicles.
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