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 (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 (volkswagen) by admin on 22-03-2011
Note: There are two different fuel filter systems. In system 1, the fuel filter is located on the engine, under the engine cover. In system 2, the fuel filter is located to the left in the engine compartment, on the strut tower. Special tools, testers and auxiliary items required Suction pump VAS 5226 Remove engine cover Removing: Upper engine cover, removing and installing . Remove plug – arrow – from fuel filter housing water drain connector. Extract diesel fuel via water drain connection located on the side of the fuel filter housing – arrow – using V.A.G 1390 and V.A.G 1390/1 . Seal off oil plug again and tighten to 3 Nm. Remove line connectors for fuel lines Remove screws – arrows – along with connection lines to fuel filter housing Removing fuel filter cover: Remove screws – arrow – for fuel filter housing and remove cover Remove fuel filters – 3 – from cover – 1 – Note: Observe waste disposal regulations! Installing: Install new fuel filters – 3 – and replace seal – 2 – Install fuel filter cover – 1 – . Tighten screws – arrows – for fuel filter cover (8 Nm) Install line connectors for fuel lines. Note: Replace sealing ring between fuel filter covers and line unions for fuel hoses. Tighten bolts – arrows – to 8 Nm. Fuel system, bleeding In order to ensure engine starts immediately after changing fuel filter, fuel system must be bled with diagnostic tester. Connect diagnostic tester Switch ignition on. Select “Guided Functions” . Perform vehicle identification. Diagnostic testing unit, connecting .
Filed Under (Chevrolet) by admin on 19-08-2010
IMPORTANT: Inspect the fuel tank internally and clean the fuel tank if you find a restricted fuel filter. 1. Relieve the fuel system pressure. Refer to the Fuel Pressure Relief Procedure. 2. Raise the vehicle. Refer to Lifting and Jacking the Vehicle. 3. Clean all the fuel filter connections and the surrounding areas before disconnecting the fuel pipes in order to avoid possible contamination of the fuel system. 4. Disconnect the threaded fittings (1, 2) from the fuel filter. 5. Remove the fuel filter bracket bolt (4). 6. Cap the fuel pipes in order to prevent possible fuel system contamination. 7. Slide the fuel filter from the bracket. 8. Inspect the fuel pipe O-rings for cuts, nicks, swelling, or distortion. Replace the O-rings if necessary. INSTALLATION PROCEDURE 1. Slide the fuel filter into the bracket. 2. Remove the caps from the fuel pipes. NOTE: Refer to Fastener Notice in Service Precautions. 3. Connect the threaded fittings (1, 2) to the fuel filter. Tighten ^ Tighten the fittings to 25 N.m (18 lb ft)Tighten the fuel filter bracket bolt (4), to 12 N.m (106 lb in). 4. Lower the vehicle. 5. Tighten the fuel filler cap. 6. Connect the negative battery cable. 7. Use the following procedure in order to Inspect for leaks. 7.1. Turn ON the ignition, with the engine OFF, for 2 seconds. 7.2. Turn OFF the ignition for 10 seconds. 7.3. Turn ON the ignition, with the engine OFF. 7.4. Inspect for fuel leaks. 7.5. Install the engine sight shield
Filed Under (Honda) by admin on 11-12-2010
FUEL SYSTEM PRESSURE RELEASE NOTE: 1. Loosen fuel tank filler cap to relieve tank pressure. Remove fuel pump relay from underhood fuse/relay box. Start and operate engine until it stalls. Crank engine an additional 30 seconds. 2. Loosen hose clamp of fuel line on side of pressure regulator, coming from fuel line inlet distributor pipe. Cover fuel hose with a shop towel, and slowly pull hose from pressure regulator to relieve fuel pressure. When fuel stops leaking, reinstall hose and clamp. FUEL PRESSURE & FUEL PUMP RELAY TEST NOTE: Fuel Pressure 1. Relieve fuel pressure. See FUEL SYSTEM PRESSURE RELEASE . Attach Fuel Pressure Gauge Set (J-34730-1 ) and Adapter (J-35957-1 ) to Schrader fitting on fuel rail. Disconnect pressure regulator vacuum hose. Turn ignition on. Allow fuel pump to run for about 2 seconds. 2. Fuel system pressure should be about 41-46 psi (2.8-3.2 kg/cm2 ). See FUEL PUMP PERFORMANCE . Start engine and check for leaks. Connect pressure regulator vacuum hose. If engine will not start, the fuel pump relay can be by-passed. Also see appropriate CHART A-3 – ENGINE CRANKS BUT WILL NOT RUN under TROUBLE SHOOTING CHARTS. With engine idling, fuel pressure should be 25-30 psi (1.8-2.1 kg/cm2 ). NOTE: Fuel pump relay is located in engine compartment fuse/relay box. Begin basic fuel system diagnosis with testing fuel pressure. To test the fuel pump relay circuit, proceed to CHART A-5 – FUEL PUMP RELAY CIRCUIT under TROUBLE SHOOTING CHARTS. Fuel Pump Relay 1. ECM supplies power to relay as long as ECM receives ignition reference signals or starter crank signal. To run fuel pump without starting engine, remove relay and jumper terminals No. 2 and 4. See Fig. 5 and Fig. 6 . 2. To test relay, use jumper wires to ground terminal No. 4 of relay and apply battery voltage to terminal No. 2 of relay. Using ohmmeter, check for continuity between relay terminals No. 1 and 3. If continuity is not present, replace relay.