Filed Under (Jeep) by admin on 27-12-2010
FUEL PRESSURE RELEASE Fuel Rail With Fuel Pressure Test Port 1. Disconnect negative battery cable. Remove fuel tank cap to release fuel tank pressure. 2. Remove protective cap from fuel pressure test port on fuel rail. Place one end of Fuel Pressure Gauge (5069) hose into approved gasoline container. Screw remaining end of fuel pressure gauge hose onto fuel pressure test port. Fuel pressure will be released into gasoline container. 3. After fuel pressure is released, remove fuel pressure gauge hose from fuel pressure test port. Reinstall protective cap on fuel pressure test port and fuel tank cap. Reinstall negative battery cable. Fuel Rail Without Fuel Pressure Test Port 1. Remove fuel pump relay from Power Distribution Center (PDC), located near windshield washer reservoir. Refer to label on PDC cover for relay location. 2. Start engine and allow to idle until engine stalls. Attempt to start engine several times. Once engine will not restart, turn ignition off. 3. Disconnect electrical connector from any fuel injector. Connect a jumper wire between one fuel injector terminal and positive battery terminal. Connect another jumper wire to remaining fuel injector terminal. CAUTION: DO NOT apply battery voltage to fuel injector for more than 4 seconds, or fuel injector may be damaged. 4. Momentarily touch remaining end of jumper wire to negative battery terminal for no more than 4 seconds. Cover fuel line at fuel rail with shop towel before disconnecting. Disconnect fuel line. 5. Disconnect jumper wires. Reinstall electrical connector on fuel injector. Reinstall fuel pump relay. Diagnostic Trouble Codes (DTCs) may be stored in Powertrain Control Module (PCM) when ASD relay is removed. To clear DTCs from PCM, see TESTS W/CODES – 2.5L article. FUEL PRESSURE TEST
Filed Under (Isuzu) by admin on 23-12-2010
NOTE: 1. Release fuel pressure. See FUEL SYSTEM PRESSURE RELEASE . Install a fuel pressure gauge between fuel pressure regulator and fuel distributor pipe. See Fig. 1 . Bleed air from fuel line going to pressure gauge. 2. Unplug fuel pressure regulator Vacuum Switching Valve (VSV) connector on right side fender skirt. This is a 4-wire connector with Black and Blue wires in harness. PCM controls VSV to cut vacuum to fuel pressure regulator during hot engine starts. 3. Start engine and measure fuel pressure at idle. Disconnect fuel pressure regulator vacuum hose. Note fuel pressure at idle with vacuum hose disconnected (no vacuum). Fuel pressure should be 42 psi (3.0 kg/cm2 ). See FUEL PUMP PERFORMANCE . 4. If fuel pump pressure is low, check for fuel leaks, restrictions in intake side of fuel pump, leaking injectors, faulty pressure regulator or faulty fuel pump. If fuel pressure is high, check for restrictions in return line to tank or faulty pressure regulator. If pressure does not change when pressure regulator is disconnected, replace pressure regulator. 5. Reconnect pressure regulator vacuum hose and check fuel pressure (with vacuum). Fuel pressure should be 35 psi (2.4 kg/cm2 ). Apply battery voltage to VSV connector Blue wire terminal, and ground Black wire terminal (with vacuum). See Fig. 2 . Fuel pressure gauge should read about 42 psi (3.0 kg/cm2 ). If fuel pressure is not within specification, check for defective VSV. 6. Disconnect and plug vacuum hose from fuel pressure regulator. Stop engine and ensure fuel pressure remains greater than 35 psi (2.4 kg/cm2 ) for 4 minutes after engine stops. 7. If pressure drops, check for leaking injectors, faulty pressure regulator or bad check valve in fuel pump. If engine does not start, by-pass fuel pump relay to check for fuel pressure. Remove fuel pump relay from underhood fuse/relay box. Connect a fused jumper wire between terminals No. 1 and 3 of fuel pump relay connector in fuse block. See Fig. 3 and Fig. 4 . 8. If fuel pump does not operate, check for battery voltage to terminal No. 3. If battery voltage is present, check for open in fuel pump circuit. If fuel pump operates with jumper wire installed, check fuel pump relay and relay energizing circuit. Repair as necessary. Begin basic fuel system diagnosis with testing fuel pressure.
Filed Under (Ford) by admin on 25-03-2011
Fuel Charging and Controls The fuel charging and controls system consists of: fuel pressure regulator (9C968) fuel injection supply manifold (9F792) fuel injectors (9F593) fuel shut off valve solenoid (9D278) fuel pressure relief valve (9H321) injection pressure sensor engine fuel temperature sensor fuel charging wiring harness Component Location Fuel Pressure Regulator The fuel pressure regulator is located on the inside of the LH frame rail just forward of the transmission support crossmember. It is part of an assembly that includes the coalescer/filter. The fuel pressure regulator reduces the line pressure from tank pressure 20685 kPa (3000 psi) to line pressure 655 kPa (95 psi). Heating/Defrosting—Natural Gas Vehicle Fuel pressure regulator heating is provided by two 3/8-inch taps from the existing heater supply and return hoses on the RH rear of the engine. Two high-temperature 3/8-inch ID heater hoses (packaged with the front low-pressure fuel line) are used to connect the fuel pressure regulator to the tap points on the engine heater hoses. Refer to the Line — Low Pressure Fuel procedure in Section 310-01B for fuel pressure regulator heater hose replacement. Fuel Pressure Regulator Heater Hoses Fuel Injection Supply Manifold The fuel injection supply manifold delivers high-pressure fuel from the vehicle fuel supply line to the fuel injectors. The fuel injection supply manifold consists of the following: a tubular fuel rail eight fuel injector connectors a fuel pressure relief valve a fuel shut off valve solenoid mounting attachments which locate the fuel injection supply manifold and provide fuel injector retention. a fuel inlet connection which has a push-connect fitting an injection pressure sensor an engine fuel temperature sensor Fuel Injection Supply Manifold Fuel Injectors The natural gas fuel injectors are electro-mechanical devices that meter fuel delivered to the engine. The natural gas fuel injectors are mounted in the lower intake manifold (9424) and are positioned so that their tips direct fuel just ahead of the engine intake valves (6507). The natural gas fuel injector bodies consist of a solenoid and a needle and valve assembly. Natural gas fuel injectors can be identified by an aqua cap on the injector body. Fuel Shutoff Valve Solenoid The fuel shut off valve solenoid seals the upstream fuel pressure from entering the fuel injection supply manifold when the engine is not running. The fuel shut off valve solenoid is open only when it is activated by the solenoid valve (fuel pump) relay. Fuel Pressure Relief Valve The fuel pressure relief valve is located on the fuel injection supply manifold, and is used to relieve fuel system pressure from the fuel delivery system. Injection Pressure Sensor The injection pressure sensor is located on the fuel injection supply manifold, and is used to provide a signal to the powertrain control module (PCM) (12A650) that is proportional to pressure in the fuel injection supply manifold. Engine Fuel Temperature Sensor The engine fuel temperature sensor is located on the fuel injection supply manifold, and is used to provide a signal to the powertrain control module that indicates the temperature of the fuel in the fuel injection supply manifold. Fuel Charging Wiring The fuel charging wiring is a single harness that includes electrical connectors for the fuel injectors, ignition coils and various sensors, valves and senders that monitor all engine functions. Fuel Charging Wiring
Filed Under (Chevrolet) by admin on 18-03-2011
WARNING: Begin fuel system trouble shooting and diagnosis with fuel system pressure test. Relieve fuel system pressure before disconnecting any components or installing fuel pressure gauge. TBI 1. Turn ignition off for 10 seconds. Turn ignition on, and listen at fuel tank for fuel pump operation. Pump should run 2 seconds (20 seconds on models with fuel module). If fuel pump runs, go to next step. If fuel pump does not run, go to step 7). 2. If fuel pump runs, turn ignition off. Verify fuel tank has fuel. Relieve fuel pressure. See FUEL SYSTEM PRESSURE RELIEF . Remove air cleaner, and plug air cleaner vacuum ports (if equipped). Disconnect fuel line between throttle body and fuel filter. Install Fuel Pressure Gauge (J-29658A) and Adapter (J- 2968A-85) between steel fuel line and flexible hose, ahead of in-line fuel filter. 3. Turn ignition on, and note reading on pressure gauge. If fuel pressure is 9-13 psi (.63-.91 kg/cm2 ), no problems exist. If pressure is less than 9 psi (.63 kg/cm2 ), go to step 5). If pressure is greater than 13 psi (.91 kg/cm2 ), turn ignition off, and bleed fuel pressure. Disconnect fuel return line downstream of pressure gauge. Insert return line into a gasoline container. 4. Turn ignition on. If pressure is now 9-13 psi (.63-.91 kg/cm2 ), correct restriction in fuel return line between disconnected point and fuel tank. If fuel pressure is greater than 13 psi (.91 kg/cm2 ), check for restricted return line (including fuel filter) downstream of pressure gauge. If no restrictions are present, replace fuel pressure regulator (TBI 700) or fuel meter cover/pressure regulator (TBI 220). 5. Check for restricted line between in-tank fuel pump and pressure regulator. If fuel line is okay, disconnect injector connector. Turn ignition on. Gradually pinch fuel pressure gauge outlet hose. Note pressure. CAUTION: DO NOT pinch off fuel return line completely. DO NOT allow fuel pressure build-up to exceed specification, as damage to fuel pressure regulator may occur. 6. If pressure is greater than 13 psi (.91 kg/cm2 ), replace fuel pressure regulator (TBI 700) or fuel meter cover/pressure regulator (TBI 220). If pressure is less than 9 psi (.63 kg/cm2 ), check for faulty fuel pump or incorrect part. Check fuel pump coupling hose and pump inlet filter in fuel tank. On models with dual fuel tanks, check for faulty fuel tank selector valve and meter switch.
Filed Under (Dodge) by admin on 04-05-2011
Use this test in conjunction with the Fuel Pump Pressure Test and Fuel Pump Capacity Test. Check Valve Operation: The electric fuel pump outlet contains a one-way check valve to prevent fuel flow back into the tank and to maintain fuel supply line pressure (engine warm) when pump is not operational. It is also used to keep the fuel supply line full of gasoline when pump is not operational. After the vehicle has cooled down, fuel pressure may drop to 0 psi (cold fluid contracts), but liquid gasoline will remain in fuel supply line between the check valve and fuel injectors. Fuel pressure that has dropped to 0 psi on a cooled down vehicle (engine OFF) is a normal condition. When the electric fuel pump is activated, fuel pressure should immediately (1 – 2 seconds) rise to specification. Abnormally long periods of cranking to restart a hot engine that has been shut down for a short period of time may be caused by: Fuel pressure bleeding past a fuel injector(s). Fuel pressure bleeding past the check valve in the fuel pump module. 1. Disconnect the fuel inlet line at fuel rail. Refer to Fuel Tubes/Lines/Hoses and Clamps for procedures. On some engines, air cleaner housing removal may be necessary before fuel line disconnection. 2. Obtain correct Fuel Line Pressure Test Adapter Tool Hose. Tool number 6539 is used for 5/16″ fuel lines and tool number 6631 is used for 3/8″ fuel lines. Fig.7 Connecting Adapter Tool (Typical) 3. Connect correct Fuel Line Pressure Test Adapter Tool Hose between disconnected fuel line and fuel rail (Fig. 7). 4. Connect the 0 – 414 kPa (0 – 60 psi) fuel pressure test gauge (from Gauge Set 5069) to the test port on the appropriate Adaptor Tool. The DRB III Scan Tool along with the PEP module, the 500 psi pressure transducer, and the transducer-to-test port adapter may also be used in place of the fuel pressure gauge. The fittings on both tools must be in good condition and free from any small leaks before performing the proceeding test. 5. Start engine and bring to normal operating temperature. 6. Observe test gauge. Normal operating pressure should be 339 kpa ±34 kPa (49.2 psi ±5 psi) . 7. Shut engine OFF. 8. Pressure should not fall below 30 psi for five minutes . 9. If pressure falls below 30 psi , it must be determined if a fuel injector, the check valve within the fuel pump module, or a fuel tube/line is leaking. 10. Again, start engine and bring to normal operating temperature. 11. Shut engine OFF. 12. Testing for fuel injector or fuel rail leakage: Clamp OFF the rubber hose portion of Adaptor Tool between the fuel rail and the test port “T” on Adapter Tool. If pressure now holds at or above 30 psi , a fuel injector or the fuel rail is leaking.