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Have the vehicle checked for other codes and do the following tests. The vehicle should still satart with WIF indicator on.
FUEL SYSTEM
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 under FUEL SYSTEM.
After repairing fuel leak, bleed air from fuel system. See FUEL LINE BLEEDING under FUEL SYSTEM in REMOVAL, OVERHAUL & INSTALLATION - TRUCKS - DIESEL article.
FUEL HEATER
Fuel heater is located in fuel filter/water separator. See Fig. 1. 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 DELIVERY under FUEL SYSTEM in SYSTEM & COMPONENT TESTING - TRUCKS - DIESEL article. For testing of fuel heater temperature sensor, see FUEL HEATER TEMPERATURE SENSOR under SENSORS under ENGINE SENSORS & SWITCHES in SYSTEM & COMPONENT TESTING - TRUCKS - 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 FUEL HEATER RELAY under RELAYS under RELAYS & SOLENOIDS in SYSTEM & COMPONENT TESTING - TRUCKS - DIESEL article.
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.
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 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 Fig. 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 Fig. 1.
Allow water to drain until clean flow of diesel fuel exists. Rotate handle on drain valve back to CLOSE position.
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.
Fuel Transfer Pump Preliminary Inspection
Check for restricted or leaking fuel supply line to fuel transfer pump or fuel return line located on driver's side of engine. See Fig. 1. Repair fuel supply line or fuel return line if restricted or leaking.
Check for fuel leaking from fuel transfer pump. Replace fuel transfer pump if fuel is leaking. Check fuel transfer pump output pressure.
Fuel Transfer Pump Output Pressure
Clean area around filter fitting plugs, then remove plugs. See Fig. 7. Install Test Fittings (AVU1-2). Install Fuel Pressure Test Gauge (6828) at inlet port. See Fig. 7. To prevent engine starting, remove fuel injection pump relay, located in power distribution center.
Turn ignition switch to START position. Inlet pressure should be 5-7 psi. Install fuel injection pump relay. Start engine. Inlet pressure should be 10 psi. Using a scan tool, clear DTC. DTC may set when relay is removed. Check pressure drop.
Fig. 7: Checking Fuel Transfer Pump Output Pressure
Courtesy of CHRYSLER CORP.
Pressure Drop Test
Turn engine off. Move pressure gauge from inlet port to outlet port. See Fig. 7. Start engine. Outlet pressure should not be more 5 psi (0.4 kg/cm2 ) less than inlet pressure. If pressure drop is more than 5 psi (0.4 kg/cm2 ), replace fuel filter and retest pressure. If pressure drop is less than 5 psi (0.4 kg/cm2 ), check for fuel supply restriction.
Fuel Supply Restriction Test
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.
Ensure transfer pump pressure is okay. Disconnect fuel supply line at fuel transfer pump inlet. 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. Connect scan tool to module. Start engine. Check vacuum reading with engine at full throttle with no load. If vacuum reading is less than 6 in. Hg, check for fuel supply air leaks. If vacuum reading is 6 in. Hg or more, check fuel line for damage, dents and kinks. Repair as necessary. If no problem is found, remove fuel module from fuel tank and check for obstructions. Repair as necessary.
Fuel Supply Air Leak Test
NOTE:A 3' section of 1/4" I.D. Clear tubing and a 1/8" NPT fitting are required for the following test.
Clean area around filter inlet fitting plug, then remove plug. See Fig. 7. Install 1/8" NPT fitting with 1/4" nipple fitting in test port. Attach clear hose with a clamp to fitting. Place other end of hose in a fuel container. Turn ignition switch to START position, then release to RUN position without starting engine. Fuel transfer pump should run for 25 seconds. After hose has been purged, watch for any air bubbles in hose. If no bubbles exist, system is okay. If bubbles exist, check fuel line, fittings and fuel module in tank. Repair as necessary.
OVERFLOW VALVE
Fuel transfer pump delivers more fuel to fuel injection pump than needed. Surplus fuel is routed back to fuel tank by overflow valve. Overflow valve is used to secure fuel return line to side of fuel injection pump. See Fig. 1. A sticking check valve in the overflow valve may result in low power. Pressure release is set at 14 psi. (1.0 kg/cm2 ). If outlet valve is stuck closed, a DTC may set.
Clean area around outlet valve and fuel return line. Remove valve from pump and fitting. Using regulated air pressure, test valve by blowing into valve inlet. Valve should open at 14-16 psi. (1.0-1.1 kg/cm2 ). If valve does not open, replace valve. Reduce air pressure to 10 psi. (0.7 kg/cm2 ). Valve should close. If valve does not close, replace valve. Using NEW gaskets, install valve through banjo fitting into fuel injection pump. Tighten valve to 24 ft. Lbs. (30 N.M).
FUEL INJECTOR & HIGH-PRESSURE FUEL LINES
WARNING:DO NOT allow diesel fuel to contact hot engine when checking fuel injector, 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 fuel injectors.
NOTE:A leaking fuel injector or high-pressure fuel line may cause a rough idle, Black smoke, poor engine performance, poor fuel economy and fuel knock. Since a leaking high-pressure fuel line may cause the same symptoms, check for leaking high-pressure fuel line before checking fuel injector.
To determine which injector or line is malfunctioning, start engine and check each cylinder output using scan tool. If scan tool is not available, start engine and engine allow to idle. Loosen high-pressure fuel line nut at each fuel injector in turn and listen for a decrease in engine speed. Tighten high-pressure fuel line nut to 30 ft. Lbs. (40 N.M). Go to next step.
To check for a leaking high-pressure fuel line, start engine and allow engine to idle. Inspect high-pressure fuel lines and connections for signs of fuel leakage by placing cardboard over high-pressure fuel line and connection. Note if leak is being detected by fuel being sprayed onto the cardboard. If leak exists, repair leak by tightening high-pressure fuel line nut to 30 ft. Lbs. (40 N.M) or replacing high-pressure fuel line as necessary. If high-pressure fuel line is replaced, bleed air from fuel system. See FUEL LINE BLEEDING under FUEL SYSTEM in REMOVAL, OVERHAUL & INSTALLATION - TRUCKS - DIESEL article. If no leaks are found, go to next step.
Remove suspect injector. See FUEL INJECTOR under FUEL SYSTEM in REMOVAL, OVERHAUL & INSTALLATION - TRUCKS - DIESEL article. Test injector with a diesel fuel injector tester. Follow tester instructions. Replace fuel injector if fuel injector opening (pop) pressure is not 4250-4750 psi (299-334 kg/cm2 ). Replace injector if any leaks are noted at 291 psi (20 kg/cm2 ) less than opening (pop) pressure. Inspect injector for burrs, cracks, wear and plugging. Check spray pattern. If any problems are noted, replace injector.
FUEL INJECTION PUMP TIMING
Improper fuel injection pump timing may result in low power, excessive smoke and poor fuel economy. To check fuel injection pump timing, see FUEL INJECTION PUMP TIMING in ON-VEHICLE ADJUSTMENTS - TRUCKS - DIESEL article.
INTAKE MANIFOLD AIR HEATER
NOTE: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.
SUMMARY
If no faults were found while performing basic diagnostic procedures, see SELF-DIAGNOSTICS - RAM PICKUP - DIESEL article. If no diagnostic trouble codes are found in self-diagnostics, see TROUBLE SHOOTING - NO CODES - DIESEL article for diagnosis by symptom (i.E, ROUGH IDLE, NO START, etc.) Or intermittent diagnostic procedures.
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Friday, March 26th, 2010 AT 5:44 AM
