Engine Controls - Basic Engine Testing - Gasoline: Diagnosis Dodge Ram Wagon B1500

VISUAL INSPECTION

Visually inspect all electrical wiring, looking for chafed, stretched, cut or pinched wiring. Ensure electrical connectors fit tightly and are not corroded. Ensure vacuum hoses are properly routed and are not pinched or cut. Inspect air induction system for possible vacuum leaks.

Vehicles With Fuel Rail Test Port

1. Loosen fuel tank filler cap. Ensure ignition is off. Remove protective cap from fuel rail test port.
2. Place one end of Fuel Pressure Release Hose (C-4799-1) into an approved fuel container. Attach remaining end of hose to fuel rail test port. Use care, as fuel system may be under pressure. Fuel pressure will be released from fuel system. Remove hose, reinstall protective cap, and fuel tank filler cap.
3. Wait 5 seconds. Use care when disconnecting fuel lines, as some fuel pressure may still exist in fuel lines.

Note. One or more DTCs may set when fuel pump relay is removed. Clear DTCs from PCM after fuel pressure release procedure. To clear DTCs from PCM, see CLEARING DTCS under SELF-DIAGNOSTIC SYSTEM in appropriate SELF-DIAGNOSTICS article.

Vehicles Without Fuel Rail Test Port

1. Remove gas cap. Using a non-metallic tool, open flapper valve in filler neck to relieve pressure. Remove fuel pump relay from Power Distribution Center (PDC). Relays are identified on label under PDC cover. Start and run engine until it stalls. Attempt to start engine. Continue restarting engine until it will no longer run. Turn ignition off. CAUTION: DO NOT supply power to fuel injector for more than 4 seconds, or fuel injector may be damaged.
2. Disconnect any fuel injector connector. Connect a jumper wire between either fuel injector terminal and positive battery terminal. Connect another jumper wire to other fuel injector terminal. Momentarily touch other end of jumper wire to negative battery terminal.
3. Place a shop towel under fuel line quick-connector at fuel rail. Use care when disconnecting fuel lines, as some fuel pressure may still exist in fuel lines. Disconnect fuel line quick-connector. Reinstall fuel pump relay in PDC. Clear DTCs from PCM. To clear DTCs from PCM, see CLEARING DTCS under SELF-DIAGNOSTIC SYSTEM in appropriate SELF-DIAGNOSTICS article.

FUEL PUMP AMPERAGE TEST

Note. Perform FUEL PUMP AMPERAGE TEST in conjunction with FUEL PUMP CAPACITY TEST, FUEL PUMP PRESSURE TEST and FUEL PRESSURE LEAKDOWN TEST.

Scheme 1

Scheme 2

Scheme 3

Scheme 4

1. Ensure fuel tank temperature is more than 50°F (10°C). Connect DRB Low Current Shunt (LCS) adapter into DRB-III scan tool SET 1 connector. (Scheme 1) Connect DRB-III scan tool to Data Link Connector (DLC). Connect test lead cables into 10-amp (10A +) and common (-) connectors on LCS. Access MAIN MENU on scan tool. Press DVOM button.
2. Use left/right arrow keys to highlight CHANNEL 1 function on scan tool. Press ENTER 3 times. Use up/down arrow keys to high light RANGE on scan tool. Press ENTER to change from 2-amp scale to 10-amp scale. Remove Power Distribution Center (PDC) cover and remove fuel pump relay. Depending on make or model of vehicle, 3 different relays are used. Use the following procedure for appropriate relay: Type 1 Fuel Pump Relay Attach test leads from LCS adapter into PDC relay cavities No. 30 and 87. (Scheme 2) Type 2 Fuel Pump Relay Attach test leads from LCS adapter into PDC relay cavities No. 30 and 87. (Scheme 3) Type 3 Fuel Pump Relay Attach test leads from LCS adapter into PDC relay cavities No. 3 and 5. (Scheme 4) Fuel pump will be operated when LCS adapter leads are connected to relay cavities. Read fuel pump amperage from DRB scan tool screen. Amperage should be less than 10 amps. If amperage is 10 amps or more, replace fuel pump module assembly. If amperage is less than 10 amps and FUEL PUMP PRESSURE, FUEL PUMP CAPACITY and FUEL PRESSURE LEAK DOWN test readings are okay, fuel pump module is okay.

FUEL PRESSURE TEST

Note. For additional information on fuel pressure and fuel pump testing procedures, see appropriate NO TROUBLE CODE (NTC) TEST and NO START (NS) TEST in appropriate SELF-DIAGNOSTICS article.

1. Disconnect negative battery cable. Release fuel pressure. See «FUEL PRESSURE RELEASE»(ref-555-S04963818992000030800000) . Install fuel pressure gauge with hose on fuel pressure test port.
2. Start engine and allow to idle. Fuel pressure should be 44-54 psi (3.1-3.8 kg/cm 2 ). If no fuel pressure exists and engine will not start, fuel pump relay and control circuit may be defective. See «FUEL PUMP RELAY»(ref-555-S13397208822000030800000) .
3. If fuel pressure exceeds specification, fuel pump is okay, but fuel pressure regulator is defective. Replace fuel pressure regulator. Fuel pressure regulator is incorporated with the fuel filter. Fuel filter/fuel pressure regulator is located on top of fuel tank, in fuel pump module. See REMOVAL, OVERHAUL & INSTALLATION - TRUCKS & RWD VANS - GASOLINE article.

1. Disconnect negative battery cable. Release fuel pressure. See «FUEL PRESSURE RELEASE»(ref-555-S04963818992000030800000). Fuel pressure gauge is installed between fuel supply line and fuel line fitting on fuel rail.
2. To disconnect fuel supply line from fuel rail, ensure area around fuel supply line and fuel rail are clean. Note direction of latch clip installation. Latch clip is located on top of fuel supply line at fuel rail. (Scheme 5) Using 2 screwdrivers, pry latch clip upward, and remove from fuel rail.
3. Pull fuel supply line from fuel rail. Install Adapter (6923) into fuel rail. Ensure adapter is fully seated in fuel rail. Install latch clip into fuel rail, with latch clip fingers pointing downward. If latch clip will not fully seat so latch clip fingers extend downward below fitting on fuel rail, adapter may not be fully seated in fuel rail.
4. Connect fuel supply line to adapter. Ensure fuel supply line fully seats in adapter. Remove protective cap from test port, and install Fuel Pressure Gauge/Hose (5069) at test port.
5. Start engine and allow to idle. Fuel pressure should be 44-54 psi (3.1-3.8 kg/cm 2 ). If no fuel pressure exists and engine will not start, fuel pump relay and control circuit may be defective. See «FUEL PUMP RELAY»(ref-555-S13397208822000030800000).
6. If fuel pressure exceeds specification, fuel pump is okay, but fuel pressure regulator is defective. Replace fuel pressure regulator. Fuel pressure regulator is incorporated with the fuel filter. Fuel filter/fuel pressure regulator is located on top of fuel tank, in fuel pump module. See REMOVAL, OVERHAUL & INSTALLATION - TRUCKS & RWD VANS - GASOLINE article.
7. On all models, release fuel pressure. See «FUEL PRESSURE RELEASE»(ref-555-S04963818992000030800000). Remove latch clip. Remove test equipment. Before reinstalling fuel supply line, ensure fuel supply line fitting and fitting on fuel rail are clean.
8. Lubricate fuel supply line fitting and fitting on fuel rail with engine oil. Install fuel supply line on fuel rail.
9. Install latch clip into fuel rail, with latch clip fingers pointing downward. Ensure latch clip is fully seated. Latch clip fingers should extend downward below fitting on fuel rail when fully seated.
10. Pull on fuel supply line to ensure fuel supply line is fully locked on fuel rail. Reinstall negative battery cable. Start engine and check for fuel leaks.

Scheme 5

FUEL PRESSURE LEAKDOWN TEST

Note. Perform FUEL PRESSURE LEAKDOWN TEST in conjunction with FUEL PUMP CAPACITY TEST and FUEL PUMP PRESSURE TEST. See FUEL PUMP CAPACITY TEST and FUEL PUMP PRESSURE TEST.

1. Release fuel system pressure. See FUEL PRESSURE RELEASE. Remove air cleaner housing (if necessary) to access quick-connect fuel fittings. Disconnect fuel supply line quick-connect fittings at fuel rail. Connect Fuel Line Pressure Test Adapter (6539 ) for 5/16" fuel lines, or Fuel Line Pressure Test Adapter (6631 ) for 3/8" fuel lines, to the disconnected fuel supply line.
2. Connect 0-60 psi fuel pressure test gauge to test port on appropriate Fuel Line Pressure Test Adapter. Start engine and bring to normal operating temperature. Observe fuel pressure test gauge. Fuel system pressure should be 44-54 psi (3.1-3.8 kg/cm 2 ). Shut engine off. Fuel system pressure should not fall below 30 psi (2.1 kg/cm 2 ) for 5 minutes. Go to next step.
3. If fuel system pressure falls below 30 psi (2.1 kg/cm 2 ), check fuel injector, check valve inside fuel pump module or fuel tube/line for leaks. To diagnose components and pinpoint fuel system leaks, perform the following tests: Fuel Injector Or Fuel Rail Leakage Start engine and operate at idle for 2 minutes. Shut off engine. Clamp off rubber hose portion of Fuel Line Pressure Test Adapter between fuel rail and test port "Tee" on Fuel Line Pressure Test Adapter. If fuel system pressure does not fall below 30 psi (2.1 kg/cm 2 ) for 5 minutes, fuel injector or fuel rail is leaking. Repair as necessary. Fuel Pump Check Valve, Filter/Regulator Check Valve Or Fuel Tube/Line Leakage Start engine and operate at idle for 2 minutes. Shut off engine. Clamp off rubber hose portion of Fuel Line Pressure Test Adapter between vehicle fuel line and test port "Tee" on Fuel Line Pressure Test Adapter. If fuel system pressure does not fall below 30 psi (2.1 kg/cm 2 ) for 5 minutes, fuel rail and fuel injectors are not leaking. Check fuel lines and tubes for leakage. If fuel lines and tubes are okay, check electric fuel pump or filter/regulator check valves for leakage. A quick loss of fuel system pressure usually indicates defective check valve in the filter/regulator. A slow loss of pressure usually indicates a defective check valve in the electric fuel pump. Repair as necessary.

NO-START TESTING PROCEDURES

For no-start testing procedures, see TEST NS-1A in appropriate SELF-DIAGNOSTICS article.