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Wiring diagrams Section: Testing & Diagnostics

Engine System Testing & Engine Component Testing - Ram Pickup, Ram Van & Ram Wagon - Gasoline: Specifications
Engine System Testing & Engine Component Testing - Ram Pickup, Ram Van & Ram Wagon - Gasoline: Diagnosis
Engine System Testing & Engine Component Testing - Ram Pickup, Ram Van & Ram Wagon - Gasoline: Other

O2 Sensor Location & Identification

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Engine Controls - Basic Diagnostic Procedures - Trucks - Diesel: Other Dodge Cab & Chassis R2500

Testing & Diagnostics 7 illustrations ~3245 words

CHECKING ENGINE MECHANICAL SYSTEMS

At this point in diagnostic test procedure, all engine control systems have been determined to be operating as designed and not causing a driveability problem. Following additional items should be checked as possible causes

Check for malfunctioning fuel injection pump or incorrect fuel injection pump timing.
Check for air in fuel system.
Check for restricted or damaged fuel injector nozzle.
Check for improper fuel.
Check for restricted fuel filter.
Check for restricted fuel injection lines.
Check for leaking or damaged fuel injection lines or loose connections.
Check for empty fuel tank or restricted fuel tank vent.
Check for restricted air filter.
Check for restricted or leaking intercooler.
Check for low or uneven engine compression.

Compression

Manufacturer does not provide information for checking compression.

AIR IN FUEL SYSTEM

Note. Air in the fuel system may cause hard starting, rough running, excessive smoke, poor engine performance, engine misfire, poor fuel economy and fuel knock. Air may enter fuel system whenever fuel supply lines, fuel filter/water separator, fuel injection pump, fuel injectors or high-pressure fuel lines are removed or disconnected.

Inspect all low-pressure fuel lines from fuel tank to fuel transfer pump, fuel heater and fuel filter/water separator for signs of leakage. Inspect all high-pressure fuel lines for signs of leakage. See «FUEL INJECTOR & HIGH-PRESSURE FUEL LINES»(ref-97352-S33002344102001050200000) under FUEL SYSTEM.
After repairing fuel leak, bleed air from fuel system. See «BLEEDING AIR FROM FUEL SYSTEM»(ref-97352-S12672373912001052200000) .

BLEEDING AIR FROM FUEL SYSTEM

WARNING

DO NOT allow diesel fuel to contact hot engine when checking high-pressure fuel lines or fuel injectors, as high exhaust temperatures could cause fire. Use care when working around high-pressure fuel lines, as fuel is under extreme pressure and could penetrate skin, causing personal injury. Wear safety goggles and protective clothing when checking high-pressure fuel lines or fuel injectors.

Note. If fuel tank has been run dry or replaced, fuel injection pump or high-pressure fuel lines have been replaced or vehicle has not been operated for an extended amount of time, air will be present in fuel system.

Loosen, but do not remove, banjo bolt low pressure fuel injection pump supply line next to overflow valve. (Scheme 72) Place a shop rag around banjo fitting. Fuel transfer pump will need to be energized to bleed air from system.
If scan tool is available, connect scan tool to Data Link Connector (DLC). Turn ignition on with engine off. Using scan tool, actuate fuel transfer pump. If fuel does not flow from banjo fitting, repeat procedure until fuel is present.
If scan tool is not available, crank engine momentarily without starting. Fuel transfer pump will run for approximately 25 seconds. If fuel does not flow from banjo fitting, repeat procedure until fuel is present. After bleeding, tighten banjo bolt to 18 ft. lbs. (24 N.m).
Attempt to start engine. If engine does not start, go to next step. If engine starts and runs erratically and noisy for the first few minutes and then smooths out, this is okay. Go to step 6. CAUTION: DO NOT crank engine for longer than 30 seconds or damage to starter motor will occur. Allow 2 minutes between cranking intervals.
Crank engine in 30 second intervals to allow air trapped in fuel injection pump to vent to drain manifold. Engine may start during this process. If engine starts and runs erratically and noisy for the first few minutes and then smooths out, this is okay. Go to next step. WARNING: DO NOT allow diesel fuel to contact hot engine when checking high-pressure fuel lines or fuel injectors, as high exhaust temperatures could cause fire. Use care when working around high-pressure fuel lines, as fuel is under extreme pressure and could penetrate skin, causing personal injury. Wear safety goggles and protective clothing when checking high-pressure fuel lines or fuel injectors.
Clean area around injector fittings and high-pressure fuel lines. While engine is running, loosen fittings at injectors for cylinders No. 3, 4 and 5. Continue bleeding injectors until engine runs smooth. After engine runs smooth, bleeding procedure is complete. Tighten injector fittings to 28 ft. lbs. (38 N.m).

Scheme 72

CHECKING FUEL DELIVERY

Note. Due to very small vacuum specifications, use a scan tool and Periphal Expansion Port (PEP) module with 0-15 psi transducer to perform following test. After completing any repairs, perform TEST VER-2A under VERIFICATION TESTS in SELF-DIAGNOSTICS - RAM PICKUP - DIESEL article.

Ensure ignition is off. Install Fuel Pressure Gauge (6828) on inlet fuel pressure test port. (Scheme 72) Turn ignition on with engine off. Using scan tool, actuate fuel transfer pump and note fuel pressure reading. Record fuel pressure. If fuel pressure is more than 10 psi (.70 kg/cm 2 ), go to next step. If fuel pressure is 10 psi (.70 kg/cm 2 ) or less, go to step 6.
Stop actuation of fuel transfer pump. Turn ignition off. Inspect fuel lines for leaks, kinks or restrictions. See «FUEL LINES»(ref-97352-S11681216172001052400000). If fuel lines are okay, go to next step. If fuel lines are leaking, kinked or restricted, repair or replace fuel lines as necessary.
Ensure fuel pressure gauge is still connected to inlet fuel pressure test port. Turn ignition on with engine off. Using scan tool, actuate fuel transfer pump and note fuel pressure reading. Record fuel pressure. Stop actuation of fuel transfer pump. Turn ignition off. Remove fuel pressure gauge from inlet fuel pressure test port and reconnect fuel pressure gauge to outlet fuel pressure test. (Scheme 72) Turn ignition on with engine off. Using scan tool, actuate fuel transfer pump and note fuel pressure reading. Record fuel pressure. Stop actuation of fuel transfer pump. Turn ignition off. If difference between fuel pressure at outlet fuel pressure test port and fuel pressure at inlet fuel pressure test port is 5 psi (.35 kg/cm 2 ) or less, go to next step. If difference between fuel pressure at outlet fuel pressure test port and fuel pressure at inlet fuel pressure test port is more than 5 psi (.35 kg/cm 2 ), replace fuel filter.
Using tire valve core remover/installer, remove valve core from inside inlet fuel pressure test port at fuel filter/water separator. Connect clear fuel line at fuel inlet port and secure in place using hose clamp. Place other end of clear line in fuel container. Turn ignition on. Using scan tool, actuate fuel transfer pump. Allow air to purge from clear fuel line and then check fuel flow for air bubbles. If no air bubbles exist in the fuel flow, go to next step. If air bubbles exist in the fuel flow, repair loose or leaking fuel supply line between fuel filter/water separator and fuel pump module on fuel tank, or leaking fuel pump module. Fuel pump module is located on top of fuel tank and contains fuel level sensor along with fuel supply and return line fittings.
Install fuel pressure gauge on inlet fuel pressure test port if previously removed. Remove fuel pump relay from power distribution center. (Scheme 73) Power distribution center is located at driver's side front corner of engine compartment. see scheme 2Crank engine and note fuel pressure reading. If fuel pressure is more than 7 psi (.50 kg/cm 2 ), test is complete. If fuel pressure is 7 psi (.50 kg/cm 2 ) or less, replace ECM. See REMOVAL, OVERHAUL & INSTALLATION - RAM PICKUP - DIESEL article. ECM is located on driver's side of engine, just in front of fuel transfer pump and contains a 50-pin connector. see scheme 1 NOTE: Due to very small vacuum specifications, use a scan tool and Periphal Expansion Port (PEP) module with 0-15 psi transducer to perform following step.
Stop actuation of fuel transfer pump. Turn ignition off. Disconnect fuel supply line-to-fuel transfer pump quick connect fitting at left rear of engine. Carefully remove plastic clip from pump inlet and install in end of fuel supply line. Install 3/8" Adapter Hose (6631 ) between fuel supply line and pump inlet. Install transducer from PEP module to "T" fitting on adapter. Turn ignition on with engine off. Using scan tool, actuate fuel transfer pump and note vacuum reading. If vacuum is more than 6 in. Hg, go to next step. If vacuum is 6 in. Hg or less, replace fuel transfer pump.
Stop actuation of fuel transfer pump. Turn ignition off. Remove vacuum gauge. At this time, it is assumed that a leak exists in fuel line or restriction exists in fuel supply line between fuel transfer pump and the fuel tank. It may be possible that in-tank fuel filter on fuel pump module is restricted. Fuel pump module is located on top of fuel tank and contains fuel level sensor along with fuel supply and return line fittings. Fuel pump module may also be referred to as fuel tank module. Repair or replace components as necessary.

Scheme 73

FUEL FILTER/WATER SEPARATOR

Note. A blocked or restricted fuel filter/water separator may cause starting problems, prevent engine from accelerating, low power or White smoke. If an excessive amount of water collects in filter/separator in a short period of time, it may be necessary to drain and clean fuel tank. This procedure does not diagnose fuel filter/water separator, only operation and servicing procedures.

When ignition switch is first turned to ON position, WATER-IN-FUEL (WIF) warning light should come on for 2 seconds to perform bulb and wiring circuit test and then go off. WATER-IN-FUEL (WIF) warning light is located on instrument panel, just below the tachometer. If WIF light does not operate properly, go to WATER-IN-FUEL LIGHT under FUEL SYSTEMS in SYSTEM & COMPONENT TESTING - RAM PICKUP - DIESEL article.
If WATER-IN-FUEL (WIF) warning light stays on, water should be drained from fuel filter/water separator. To drain water from fuel filter/water separator, ensure engine is not running. Place drain pan below drain tube at fuel filter/water separator. see scheme 1
Rotate handle on drain valve forward, toward front of vehicle to OPEN position. Drain valve is located near top of fuel filter/water separator. see scheme 3
Allow water to drain until clean flow of diesel fuel exists. Rotate handle on drain valve back to CLOSE position.

FUEL HEATER

Note. Fuel heater is located in fuel filter/water separator. see scheme 3 Fuel heater uses a fuel heater temperature sensor for controlling operation of the fuel heater. A defective fuel heater may cause excessive wax build-up in the fuel filter/water separator during cold ambient temperatures. Wax build-up may cause hard starting, prevent engine from accelerating, low power, Blue smoke or White smoke.

For testing of fuel heater, see FUEL HEATER under FUEL SYSTEM in SYSTEM & COMPONENT TESTING - RAM PICKUP - DIESEL article. For testing of fuel heater temperature sensor, see FUEL TEMPERATURE SENSORS under SENSORS under ENGINE SENSORS & SWITCHES in SYSTEM & COMPONENT TESTING - RAM PICKUP - DIESEL article.

FUEL HEATER RELAY

Ensure fuel heater relay, located in power distribution center is installed correctly and that terminals are not corroded. For fuel heater relay testing, see A/C CLUTCH, AUTO SHUTDOWN (ASD), FUEL HEATER & FUEL PUMP RELAYS under RELAYS & SOLENOIDS in SYSTEM & COMPONENT TESTING - RAM PICKUP - DIESEL article.

FUEL INJECTION PUMP TIMING

Ensure fuel transfer pump output pressure is within specification before condemning fuel injection pump. See «FUEL TRANSFER PUMP PRESSURE TEST»(ref-97352-S21886946582001050200000) under FUEL TRANSFER PUMP. No mechanical adjustments are needed for fuel injection timing. All timing and fuel adjustments are made by Engine Control Module (ECM). If a DTC has been stored indicating an ENGINE SYNC ERROR or STATIC TIMING ERROR, go to next step.
Remove crankcase vent hose and breather from gear cover. Breather threads into cover. Remove injection pump nut and washer. Locate keyway behind washer. Ensure keyway aligning fuel injection pump shaft to injection pump gear is in correct position and pump gear has not slipped on pump shaft.
Remove timing gear cover to access timing gears. See 5.9L (24-VALVE) 6-CYLINDER DIESEL article in ENGINES. Use a "T" puller and separate injection pump gear from pump shaft. (Scheme 74) Ensure keyway is installed with arrow toward rear of pump. (Scheme 75)
Pump timing is calibrated to pump keyway. Ensure 3-digit number on pump keyway matches 3-digit number on fuel injection pump data plate on side of injection pump. (Scheme 75) Twenty one different calibrated keyways/pumps are available. Ensure timing marks on crank, camshaft and pump align. (Scheme 76) Align gears as necessary. After repair, erase any DTCs using scan tool.

Scheme 74

Scheme 75

Scheme 76

FUEL TRANSFER PUMP

Note. A defective fuel transfer pump may cause low power, hard starting and White smoke. Check fuel transfer pump output pressure (cranking and starting), pressure drop and fuel supply.

OVERFLOW VALVE

See OVERFLOW VALVE under FUEL SYSTEMS in SYSTEM & COMPONENT TESTING - RAM PICKUP - DIESEL article.

INTAKE MANIFOLD AIR HEATER

Intake manifold air heater is used to heat incoming air before entering each cylinder. Warming of incoming air aids in engine starting and improved driveability during cold ambient temperatures. Engine Control Module (ECM) uses input signals from various sensors for controlling intake manifold air heater relays. For testing intake manifold air heater, see INTAKE MANIFOLD AIR HEATER (IMAH) SYSTEM under AIR INDUCTION SYSTEMS in SYSTEM & COMPONENT TESTING - RAM PICKUP - DIESEL article.

ENGINE WILL NOT CRANK

Note. For connector terminal ID, see CONNECTOR IDENTIFICATION. For starter relay wiring diagram, see appropriate STARTERS article in STARTING & CHARGING SYSTEMS. After completing any repair, perform TEST VER-1A under VERIFICATION TESTS in SELF-DIAGNOSTICS - RAM PICKUP - DIESEL article.

Disconnect negative battery cables and wait 2 minutes. Attempt to rotate crankshaft one full revolution by hand to ensure engine is not seized. If crankshaft rotates one full revolution, go to next step. If crankshaft will not rotate one full revolution, repair engine mechanical problem.
Locate and disconnect Park/Neutral Position (PNP) switch connector. PNP switch is located on driver's side of transmission, just below shift cable lever. Using DVOM, backprobe and measure resistance between ground and PNP switch connector terminal No. 2 (Black/White wire). (Scheme 77) Move gear shift lever through all positions. If resistance changes from more than 10 ohms to less than 10 ohms, go to next step. If resistance does not change from more than 10 ohms to less than 10 ohms, replace PNP switch. See REMOVAL, OVERHAUL & INSTALLATION - RAM PICKUP - DIESEL article.
Check for voltage drop in battery cables. If voltage drop is less than 0.2 volt, go to next step. If voltage drop is more than 0.2 volt, repair high resistance in suspect battery cable.
Locate and remove starter relay from Power Distribution Center (PDC). see scheme 2and (Scheme 73). On A/T equipped vehicles, ensure gear shift lever is in Park and parking brake is applied. Briefly connect a fused jumper wire between starter relay connector terminals No. 85 and 86. If starter motor cranks engine, go to next step. If starter motor does not crank engine, go to step 7.
Turn ignition on. Using a test light connected to ground, probe starter relay connector terminal No. 86. If test light illuminates, go to next step. If test light does not illuminate, repair open or high resistance in Yellow or Yellow/Red wire between PDC and ignition switch.
Turn ignition off. Locate and disconnect Powertrain Control Module (PCM) connectors. see scheme 2 Using DVOM, measure resistance of Black/White wire between PCM connector C1 terminal No. 6 and starter relay connector terminal No. 85 in PDC. (Scheme 78) If resistance is less than 5 ohms, replace starter motor relay. If resistance is 5 ohms or more, repair open in Black/White wire.
Disconnect starter motor solenoid connector. Using DVOM, measure resistance of Brown wire between starter motor solenoid and starter relay connector terminal No. 87 in PDC. If resistance is less than 5 ohms, go to next step. If resistance is 5 ohms or more, repair open in Brown wire.
Using a test light connected to ground, probe starter relay connector terminal No. 30 in PDC. If test light illuminates, replace starter. If test light does not illuminate, repair open in Yellow wire between starter relay and fuse No. 9 (30-amp) located in PDC. Also check for blown fuse. If Yellow wire and fuse are okay, repair open in Red wire between PDC and battery. If fuse is blown, repair short to ground in Red or Yellow wires.

Scheme 77

Scheme 78

ENGINE WILL NOT START OR HARD TO START (EXHAUST SMOKE PRESENT WHEN CRANKING)

Note. After completing any repair, perform TEST VER-1A under VERIFICATION TESTS in SELF-DIAGNOSTICS - RAM PICKUP - DIESEL article.

Check for any Technical Service Bulletins (TSB) or ECM calibration updates that may apply.
Low fuel level.
Low battery voltage.
Plugged fuel filter.
Poor quality or improper grade of fuel.
Fuel tank venting malfunction.
Low fuel pressure. See «CHECKING FUEL DELIVERY»(ref-97352-S16507018052001050200000) under FUEL SYSTEM.
Air in fuel system. See «FUEL TRANSFER PUMP»(ref-97352-S06121402372001050200000) under FUEL SYSTEM.
Lift pump malfunctioning. See «FUEL TRANSFER PUMP»(ref-97352-S06121402372001050200000) under FUEL SYSTEM.
Fuel inlet restricted. See «FUEL LINES & FUEL INJECTORS»(ref-97352-S11681216172001052400000) under FUEL SYSTEM.
Fuel injection pump static timing. See «FUEL INJECTION PUMP TIMING»(ref-97352-S05311609772001050200000) under FUEL SYSTEM.
Kinked or restricted fuel inlet line.
Kinked or restricted fuel return line.
Incorrect injectors.
Incorrect injector shim thickness.
Malfunctioning injectors.
Leaking fuel connection.
Engine speed sensor and/or circuit malfunction. See SYSTEM & COMPONENT TESTING - RAM PICKUP - DIESEL article.
Moisture in harness and/or connectors.
Internal engine damage. See «PRELIMINARY INSPECTION & ADJUSTMENTS»(ref-97352-S19828694282001050200000) .
Restricted air intake.
Restricted exhaust.
Fuel inlet temperature too high.
Overhead adjustments.
Ignition switch output voltage low and/or open. See POWER DISTRIBUTION article in WIRING DIAGRAMS.
Malfunctioning engine block or fuel line heaters (cold weather condition). See «FUEL HEATER»(ref-97352-S17429345312001050200000) under FUEL SYSTEM.
Malfunctioning fuel pump overflow valve. See «OVERFLOW VALVE»(ref-97352-S33603173852001050200000) under FUEL SYSTEM.
Engine cranking speed too slow. See appropriate STARTERS article in STARTING & CHARGING SYSTEMS.
Electrical interference (noise).

ENGINE WILL NOT START OR HARD TO START (NO EXHAUST SMOKE PRESENT WHEN CRANKING)