Engine Controls - Basic Engine Testing - Gasoline Dodge Cab & Chassis R2500

INTRODUCTION

The following diagnostic steps will help prevent overlooking a simple problem. This is also where to begin diagnosis for a no-start condition.

The first step in diagnosing any driveability problem is verifying the customer's complaint with a test drive under the conditions the problem reportedly occurred.

Before entering self-diagnostics, perform a careful and complete visual inspection. Most engine control problems result from mechanical breakdowns, poor electrical connections or damaged/misrouted vacuum hoses. Before condemning the computerized system, perform each test listed in this article.

Note. Perform all voltage tests with a Digital Volt-Ohmmeter (DVOM) with a minimum 10-megohm input impedance, unless stated otherwise in test procedure.

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.

Compression

Ensure battery is fully charged. Warm engine to normal operating temperature. Disconnect wire at ignition coil to prevent engine from starting. Check engine compression with all spark plugs removed and throttle wide open.

Check engine mechanical condition with a compression gauge, vacuum gauge, or an engine analyzer. See engine analyzer manual for specific instructions.

COMPRESSION SPECIFICATIONS

FUEL PRESSURE RELEASE

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 PUMP CAPACITY TEST

Note. Perform FUEL PUMP PRESSURE TEST before performing FUEL PUMP CAPACITY TEST. Perform FUEL PUMP CAPACITY TEST in conjunction with FUEL PRESSURE LEAKDOWN TEST. See FUEL PRESSURE LEAKDOWN 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. Insert other end of Fuel Line Pressure Test Adapter into a graduated container. Remove fuel filler cap. Using DRB scan tool, actuate ASD FUEL SYSTEM TEST. This should activate fuel pump and pressurize system. Fuel pump should deliver at least .25 L of fuel in 7 seconds. If capacity is lower than specification, but fuel pump can be heard through fuel filler, check for a kinked or damaged fuel supply line between fuel rail and fuel pump module. Go to next step.
3. If fuel supply line is not kinked or damaged and fuel pressure is okay, but capacity is low, replace fuel filter/fuel pressure regulator. Fuel pressure regulator can be replaced separately on some models. If both fuel capacity and pressure are low, replace fuel pump module assembly. See FUEL PUMP MODULE under FUEL SYSTEM in REMOVAL, OVERHAUL & INSTALLATION - TRUCKS & RWD VANS - GASOLINE article.

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»(/dodge/cab-chassis-r2500/1996-2002/remont/testing-diagnostics/#engine-controls-basic-engine-testing-gasoline__fuel-pressure-release) . 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»(/dodge/cab-chassis-r2500/1996-2002/remont/testing-diagnostics/#engine-controls-basic-engine-testing-gasoline__fuel-pump-relay) .
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»(/dodge/cab-chassis-r2500/1996-2002/remont/testing-diagnostics/#engine-controls-basic-engine-testing-gasoline__fuel-pressure-release). 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»(/dodge/cab-chassis-r2500/1996-2002/remont/testing-diagnostics/#engine-controls-basic-engine-testing-gasoline__fuel-pump-relay).
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»(/dodge/cab-chassis-r2500/1996-2002/remont/testing-diagnostics/#engine-controls-basic-engine-testing-gasoline__fuel-pressure-release). 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.

FUEL PUMP RELAY

On all models, if fuel pump relay or control circuit becomes defective, a Diagnostic Trouble Code (DTC) may be stored in the PCM. For additional information on diagnosis for fuel pump relay and control circuit, see TEST TC-101A in appropriate SELF-DIAGNOSTICS article.

3.9L, 5.2L & 5.9L

1. Disconnect ignition coil secondary cable from center tower of distributor cap. Hold cable terminal about 1/2" (12 mm) from a good engine ground. Crank engine and observe cable terminal for a steady arc. If steady arcing occurs, go to step 3 . If steady arcing does not occur, go to next step.
2. Check secondary coil cable resistance. Resistance should be 3000-12,000 ohms per foot. Also, inspect distributor cap and rotor for cracks or burn marks. If problem is found, repair as necessary. If problem is not found, go to next step.
3. Connect ignition coil cable to distributor cap. Remove a cable from one spark plug. Using insulated pliers, hold cable terminal about 1/2" (12 mm) from engine cylinder head or block while cranking engine.
4. If steady arcing occurs, it can be expected that ignition secondary system is operating correctly. If steady arcing occurs, but engine will not start, see appropriate NO START (NS) TEST in appropriate SELF-DIAGNOSTICS article.

8.0L

Information is not available from manufacturer.

IGNITION COIL

Note. For a complete test of ignition coil and its circuits, see TEST NTC-2A in appropriate SELF-DIAGNOSTICS article. Perform the following to test ignition coil only.

IGNITION COIL RESISTANCE - Ohms @ 70-80°F (21-27°C)

Inspect ignition coil for arcing. Test coil according to coil tester manufacturer's instructions. Test coil primary and secondary resistance. See IGNITION COIL RESISTANCE - OHMS @ 70-80°F (21-27°C) table. Replace coil if resistance is not with specification of if there is evidence or arcing.

1. To test secondary resistance of each individual paired coil, attach an ohmmeter across coil towers. This must be done across corresponding cylinders (3/2, 7/4, 1/6, 9/8 or 5/10). (Scheme 6) See «IGNITION COIL RESISTANCE - OHMS @ 70-80°F (21-27°C)»(/dodge/cab-chassis-r2500/1996-2002/remont/testing-diagnostics/#engine-controls-basic-engine-testing-gasoline) table.
2. To test primary resistance of front coil pack, attach an ohmmeter between B+ coil terminal and corresponding coil terminal. (Scheme 7) Replace coil pack if resistance is not as specified.

Scheme 6

Scheme 7

NO-START TESTING PROCEDURES

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

IDLE SPEED & IGNITION TIMING

Idle speed and mixture are controlled by Powertrain Control Module (PCM). No adjustment is required. PCM controls Idle Air Control (IAC) motor for proper idle speed. See TEST TC-25A in appropriate SELF-DIAGNOSTICS article.

Ignition timing is controlled by PCM and is nonadjustable. If vehicle is equipped with a distributor, DO NOT attempt to adjust timing by rotating distributor. If distributor is rotated, fuel system synchronization will be changed. If distributor is rotated or removed, check fuel system synchronization. See FUEL SYSTEM SYNCHRONIZATION under FUEL SYSTEM in ON-VEHICLE ADJUSTMENTS - TRUCKS & RWD VANS - CNG & GASOLINE article.

SUMMARY

If no faults were found while performing basic diagnostic procedures, proceed to appropriate SELF-DIAGNOSTICS article. If no diagnostic trouble codes are found in self-diagnostics, proceed to TROUBLE SHOOTING - NO CODES - GASOLINE article for diagnosis by symptom (i.e., ROUGH IDLE, NO-START, etc.) or intermittent diagnostic procedures.

See also:
• FUEL PRESSURE RELEASE
• FUEL PUMP RELAY
• IGNITION COIL RESISTANCE - OHMS @ 70-80°F (21-27°C)