Engine Controls - Basic Testing - 5.9l Diesel Dodge Pickup R3500

INTRODUCTION

Note. Article applies only to 12-valve engine with mechanical fuel injection. Article does not apply to 24-valve engine with electronic fuel injection.

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 or poor electrical connections. Before condemning the computerized system, perform each test listed in this article.

Although various components, relays and switches are controlled and monitored by the PCM, the diesel injection system is not directly controlled by the PCM. For PCM system diagnosis, see appropriate TESTS W/CODES - DIESEL article.

Scheme 5

Scheme 6

Scheme 7

Scheme 8

Scheme 9

1. Check Water-In-Fuel (WIF) sensor electrical connector for corrosion, damaged terminals or wiring and tight fit on engine wiring harness. WIF sensor is located in bottom of fuel filter/water separator. (Scheme 10)
2. Check for water in fuel filter/water separator by placing drain pan below drain tube at fuel filter/water separator. (Scheme 10)
3. With engine not running, rotate handle on drain valve forward, toward front of vehicle to DRAIN position. Drain valve is located near top of fuel filter/water separator. (Scheme 10) Drain water from fuel filter/water separator.
4. If no water exists and a clean flow of diesel fuel exists, rotate handle on drain valve back to CLOSE position. Go to next step. If water exists, allow water to drain until clean flow of diesel fuel exists. Rotate handle on drain valve back to CLOSE position. Go to next step.
5. Verify fuel filter/water separator has been serviced according to proper service schedule. See SERVICE INTERVALS & SPECIFICATIONS under QUICK-SERVICE in SPECIFICATIONS - DIESEL article. Ensure pre-filter was cleaned when fuel filter/water separator was serviced. Pre-filter is located at bottom of fuel heater on driver's side of engine. (Scheme 10)
6. Check color of Filter Minder. Filter Minder is located on top cover on air filter housing, just above air filter. DO NOT remove air filter from air filter housing for inspection. If Yellow disc in Filter Minder has reached Red zone, remove and inspect air filter. (Scheme 5) If air filter is dirty, replace air filter and reset Filter Minder by pressing rubber button on top of Filter Minder. NOTE: The Yellow disc in Filter Minder may reach Red zone if air intake is restricted or air filter has become wet during heavy rain or snow. If air filter has become wet, allow air filter to dry during normal engine operation and reset Filter Minder by pressing rubber button on top of Filter Minder.
7. Ensure intercooler inlet and outlet duct clamps are tight and front of intercooler is not restricted with dirt. (Scheme 6)
8. Check for proper control rod adjustment for turbocharger wastegate. See CONTROL ROD ADJUSTMENT under TURBOCHARGER WASTEGATE in ADJUSTMENTS - DIESEL article.
9. Check for proper linkage rod adjustment at fuel injection pump. See LINKAGE ROD ADJUSTMENT under THROTTLE LINKAGE in ADJUSTMENTS - DIESEL article.
10. On A/T models and M/T models with EGR, check adjustment of throttle position sensor. See THROTTLE POSITION SENSOR ADJUSTMENT under THROTTLE POSITION SENSOR in ADJUSTMENTS - DIESEL article.
11. On all models, ensure connections on both batteries are tight and not corroded. Ensure the three 32-pin connectors are fully engaged on Powertrain Control Module (PCM). PCM is located on firewall at passenger's side rear corner of engine compartment.
12. Check for loose, defective or corroded connections at fuel shutdown solenoid and intake manifold air temperature sensor. (Scheme 7)
13. Ensure electrical connections on intake manifold air heater relays and intake manifold air heater are tight and not corroded. Intake manifold air heater relays are mounted on inner wheelwell, below driver's side battery. (Scheme 8) Intake manifold air heater is located between air inlet housing and intake manifold cover. (Scheme 9) NOTE: Restricted low-pressure fuel lines from fuel tank to fuel transfer pump, fuel heater and fuel filter/water separator may cause starting problems and prevent engine from accelerating. Restricted high-pressure fuel lines from fuel injection pump to fuel injector may cause starting problems, poor engine performance and excessive Black smoke.
14. Check all fuel supply and returns lines for damage, kinking or leakage. Check throttle linkage and accelerator linkage for binding. Check for a stretched or disconnected throttle return spring.
15. Ensure all ground connections are tight and free of corrosion. Ensure accessory drive belt is not damaged or slipping.
16. Check for loose or defective electrical connection on engine speed sensor. Engine speed sensor is located at front of engine, above vibration damper. Engine speed sensor may be referred to as crankshaft position sensor.
17. On A/T models, ensure all electrical connectors are clean and properly connected to electrical plugs on transmission case. On all models, check for loose or defective electrical connections on starter and starter solenoid.

Scheme 10

Compression

Manufacturer does not provide information for checking compression.

FUEL SHUTDOWN SOLENOID OPERATION

Note. Ensure fuel shutdown solenoid operates correctly. If fuel shutdown solenoid fails to operate correctly, engine may fail to start or may shut off during operation.

Fuel Shutdown Solenoid (Preliminary Inspection)

1. Ensure ignition switch is in OFF position. Check that lever pin on fuel shutdown solenoid is extended downward and pump lever is in SHUTDOWN position. (Scheme 11)
2. Turn ignition switch to START position while noting operation of lever pin and pump lever. Lever pin and pump lever should move upward to the RUN position. (Scheme 11) Release ignition switch from START position to the ON position. Ensure lever pin and pump lever remain in the RUN position.
3. If fuel shutdown solenoid operates as specified, fuel shutdown solenoid and wiring are okay. If fuel shutdown solenoid does not operate as specified, go to appropriate procedure as follows, depending on operation of solenoid and lever pin.

Fuel Shutdown Solenoid Does Not Operate (Lever Pin Does Not Move Upward At All)

1. Disconnect fuel shutdown solenoid connector from wiring harness. (Scheme 7) While holding ignition switch in START position, use voltmeter to check voltage at Red/Violet wire terminal on wiring harness side of fuel shutdown solenoid connector. Red/Violet wire goes to the fuel shutdown solenoid relay.
2. If battery voltage exists, replace fuel shutdown solenoid. See FUEL SHUTDOWN SOLENOID under FUEL SYSTEM in REMOVE/INSTALL/OVERHAUL - DIESEL article. If battery voltage does not exist, check fuel shutdown solenoid relay. See RELAYS under RELAYS & SOLENOIDS in SYSTEM/COMPONENT TESTS - DIESEL article.
3. If fuel shutdown solenoid relay is okay, check for open circuit on Red/Violet wire between fuel shutdown solenoid relay and fuel shutdown solenoid, and for open wiring circuit from starter and fuse No. 9 (50-amp) in power distribution center to fuel shutdown solenoid relay. See appropriate wiring diagram in WIRING DIAGRAMS - DIESEL article. Fuel shutdown solenoid relay is located near brake master cylinder. (Scheme 12) Power distribution center is located at driver's side front corner of engine compartment, near fenderwell.

Scheme 11

Scheme 12

Fuel Shutdown Solenoid Operates Only With Ignition Switch In START Position (Lever Pin Moves Upward But Does Not Stay Up)

1. Disconnect fuel shutdown solenoid connector from wiring harness. (Scheme 7) Turn ignition switch to ON position.
2. Using voltmeter, check voltage at Light Green/Black wire terminal on wiring harness side of fuel shutdown solenoid connector. This is the wire from ignition switch and fuse No. 9 (10-amp) to the fuel shutdown solenoid. Fuse No. 9 is located in junction block on end of instrument panel, at driver's door opening.
3. If battery voltage exists, replace fuel shutdown solenoid. See FUEL SHUTDOWN SOLENOID under FUEL SYSTEM in REMOVE/INSTALL/OVERHAUL - DIESEL article. If battery voltage does not exist, repair open circuit on Light Green/Black wire between ignition switch and fuel shutdown solenoid. See appropriate wiring diagram in WIRING DIAGRAMS - DIESEL article.

AIR IN FUEL SYSTEM

Note. Air in the fuel system may cause hard starting, 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.

1. 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.
2. After repairing fuel leak, bleed air from fuel system. See FUEL LINE BLEEDING under FUEL SYSTEM in REMOVE/INSTALL/OVERHAUL - DIESEL article.

FUEL HEATER

1. Fuel heater is located on between the pre-filter and the fuel transfer pump. (Scheme 10) Fuel heater uses a fuel heater temperature sensor for controlling of the fuel heater.
2. 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 and fuel heater temperature sensor, see FUEL DELIVERY under FUEL SYSTEM in SYSTEM/COMPONENT TESTS - 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.

1. 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.
2. 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. (Scheme 10)
3. Rotate handle on drain valve forward, toward front of vehicle to DRAIN position. Drain valve is located near top of fuel filter/water separator. (Scheme 10)
4. 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 and then fuel transfer pump output volume. Low fuel transfer pump output pressure may also be caused by worn eccentric on engine camshaft.

Fuel Transfer Pump Preliminary Inspection

1. Check for restricted or leaking fuel supply line to fuel transfer pump or fuel return line located on driver's side of engine. (Scheme 10) Repair fuel supply line or fuel return line if restricted or leaking.
2. Check for fuel leaking from weep hole on housing of fuel transfer pump. Replace fuel transfer pump if fuel is leaking from weep hole. Check fuel transfer pump output pressure.

Fuel Transfer Pump Output Pressure

1. Place drain pan below fuel injection pump. Remove banjo bolt and gaskets, and disconnect fuel supply line from side of fuel injection pump. (Scheme 13)
2. Using Adapter (6976) and gaskets, reconnect fuel supply line on side of fuel injection pump. (Scheme 13) Install a 0-100 psi fuel pressure gauge on adapter.
3. Start engine and warm engine to normal operating temperature. Record output pressure with engine idling and then at 2500 RPM with no load. Output pressure should be 17-22 psi (117-152 kPa) at idle and 25-30 psi (172-207 kPa) at 2500 RPM with no load.
4. If output pressure is within specification, go to step 11). If output pressure exceeds specification, go to next step. If output pressure is less than specified, go to step 6).
5. High output pressure indicates a restriction. Check that overflow valve is installed on fuel return line on fuel injection, and not on the fuel supply line. Overflow valve is used to secure fuel return line on fuel injection pump. (Scheme 14) If overflow valve is installed in the improper fuel line, reinstall in correct location and recheck output pressure. If overflow valve is installed in correct location, check for fuel line restrictions.
6. Check for dirty or restricted fuel filter/water separator and pre-filter. Fuel filter/water separator and pre-filter are located on driver's side of engine. (Scheme 10) Pre-filter is located at bottom of fuel heater. (Scheme 10)
7. Change dirty or restricted fuel filter/water separator or pre-filter as necessary and recheck output pressure. If output pressure is now within specification, go to step 11). If output pressure is still less than specified, overflow valve on fuel injection pump may be defective. Overflow valve is used to secure fuel return line on fuel injection pump. (Scheme 14) Go to next step.
8. To determine if overflow valve is defective, disconnect fuel return line at rear of engine. (Scheme 10) Install Rubber Adapter Hose (6539) between fuel return line on the engine and fuel return line going back to the fuel tank. CAUTION: Rubber adapter hose must be installed when pinching fuel return line closed. DO NOT attempt to pinch fuel return line from the engine to the fuel tank closed. Fuel return line is rubber on the outside, but the inside is not rubber and the fuel return line will be damaged if it is pinched closed.
9. Carefully pinch fuel return line closed and note output pressure. If output pressure is still less than specified, go to next step. If output pressure is now within specification, check that overflow valve is installed on fuel return line on fuel injection, and not on the fuel supply line. (Scheme 14) If overflow valve is installed in correct location, replace overflow valve. If overflow valve is installed in the improper fuel line, reinstall in correct location and recheck output pressure.
10. If output pressure is still less than specified with fuel return line pinched closed, ensure fuel filter/water separator or pre-filter are in good condition. If fuel filter/water separator and pre-filter are okay, replace transfer pump.
11. Shut engine off. Remove test equipment. Reinstall fuel supply line on fuel injection pump. Install and tighten fuel supply banjo bolt to 18 ft. lbs. (24 N.m). Check fuel transfer pump output volume. See FUEL TRANSFER PUMP OUTPUT VOLUME.

Scheme 13

Scheme 14

Fuel Transfer Pump Output Volume

1. Disconnect fuel shutdown solenoid connector. (Scheme 7) This is done to prevent engine from starting, as engine must be cranking to check fuel transfer pump output volume. Connect hand-held Tachometer (3377462) to engine.
2. Remove fuel drain line-to-cylinder head clamp bolt near cylinder No. 5 rocker lever cover. This is done to prevent damage to fuel drain line when disconnecting fuel drain line from fuel filter/water separator. Remove banjo bolt and disconnect fuel drain line from fuel inlet line at top of fuel filter/water separator. (Scheme 15)
3. Using Adapter (6836), secure fuel inlet line to top of fuel filter/water separator. (Scheme 15) Connect rubber hose on adapter. Place remaining end of rubber hose in graduated container which measures ounces.
4. Crank engine for 30 seconds while noting engine cranking speed RPM. DO NOT crank engine for more than 30 seconds or starter may be damaged. Note amount of fuel volume obtained.
5. To determine fuel transfer pump output volume specification, use engine cranking speed RPM and fuel volume. (Scheme 16)
6. If fuel transfer pump output volume is less than specified, condition may be caused by a restricted fuel supply inlet line, restricted pre-filter or defective transfer pump. Remove test equipment. Reinstall fuel drain line and fuel shutdown solenoid connector.

Scheme 15

Scheme 16

OVERFLOW VALVE

Note. Overflow valve is used to secure fuel return line on fuel injection pump. (Scheme 14) A sticking check valve in the overflow valve may result in low power. Overflow valve operation may be checked when testing fuel transfer pump. See FUEL TRANSFER PUMP under FUEL SYSTEM.

FUEL INJECTOR & HIGH-PRESSURE FUEL LINES

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. Following procedure is for determining if fuel injector is defective.

1. Since a leaking high-pressure fuel line may cause the same symptoms, check for leaking high-pressure fuel line before checking fuel injector. To check for a leaking high-pressure fuel line, start engine and allow engine to idle.
2. 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 18 ft. lbs. (24 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 REMOVE/INSTALL/OVERHAUL - DIESEL article.
3. To check for defective fuel injector, start engine and engine allow to idle. Loosen high-pressure fuel line nut at fuel injector and listen for a decrease in engine speed. Tighten high-pressure fuel line nut to 18 ft. lbs. (24 N.m).
4. If fuel injector is operating properly, engine idle speed should decrease when high-pressure fuel line nut is loosened. Repeat procedure on each fuel injector.
5. If engine idle speed does not decrease, fuel injector is defective and should be removed and tested with a diesel fuel injector tester. Replace fuel injector if fuel injector opening (pop) pressure is not 3394-3887 psi (23,400-26,800 kPa).

IN-TANK FUEL FILTER

In-tank fuel filter is located on bottom of fuel tank module which also contains the fuel gauge sending unit. Fuel tank module is mounted on top of fuel tank. For servicing of in-tank fuel filter, see FUEL TANK MODULE & IN-TANK FUEL FILTER under FUEL SYSTEM in REMOVE/INSTALL/OVERHAUL - 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. Powertrain Control Module (PCM) uses input signals from various sensors for controlling intake manifold air heater relays.

Intake Manifold Air Heater Preheat/Postheat Cycle

1. Air temperature at intake manifold must be less than 59°F (15°C). Turn ignition on. The WAIT-TO-START warning light on instrument panel should come on. A click should be heard at intake manifold air heater relays, indicating start of preheat cycle. Intake manifold air heater relays are mounted on inner wheelwell, below driver's side battery. (Scheme 8) NOTE: If starter is engaged before preheat cycle is complete, Powertrain Control Module (PCM) will stop the preheat cycle.
2. Remove rubber cable terminal shields from positive battery cable connections on intake manifold air heater. Intake manifold air heater is located between air inlet housing and intake manifold cover. (Scheme 9)
3. Using voltmeter, check for voltage at both electrical terminals on intake manifold air heater. Battery voltage should exist at both terminals for 10-30 seconds, depending on intake air temperature. See HEAT CYCLE SPECIFICATIONS table. HEAT CYCLE SPECIFICATIONS Intake Air Temperature Preheat CycleWith Ignition & Engine Off Postheat Cycle On With Ignition On & Engine On Greater Than 59°F (15°C) 0 Seconds No 15°F (-10°C) To 59°F (15°C) 10 Seconds Yes 0°F (-18°C) To 15°F (-10°C) 15 Seconds Yes Below 0°F (-18°C) 30 Seconds Yes
4. If voltage exists as specified, check intake manifold air heater. If voltage does not exist as specified, check intake manifold air heater relays.

1. Disconnect negative battery cables. Remove rubber cable terminal shields from positive battery cable connections on intake manifold air heater. Intake manifold air heater is located between air inlet housing and intake manifold cover. (Scheme 9) DO NOT disconnect positive battery cables from intake manifold air heater.
2. Using ohmmeter, check resistance between ground and each positive battery cable connection. DO NOT use mounting stud for battery cables on intake manifold air heater when checking resistance. Resistance should be zero ohms.
3. If any resistance exists, check for corroded or dirty electrical connections. Clean and repair cable connections as necessary. Recheck resistance. If resistance still exists, go to next step.
4. Disconnect positive battery cable connections from intake manifold air heater. Isolate positive battery cables to prevent cables from contacting other components. Using ohmmeter, check resistance between ground and each battery cable electrical terminal on intake manifold air heater.
5. Resistance should be zero ohms. If any resistance exists, replace intake manifold air heater with intake manifold cover. Reinstall positive battery cables and negative battery cables.

Intake Manifold Air Heater Relay

1. Disconnect negative battery cables. Note location of wiring at intake manifold air heater relays for reassembly reference. Intake manifold air heater relays are mounted on inner wheelwell, below driver's side battery. (Scheme 8)
2. Disconnect all electrical connectors and cables from intake manifold air heater relays. Connect ohmmeter between large terminals on top of intake manifold air heater relay.
3. Using jumper wires, momentarily apply battery voltage to relay trigger wire terminals (small wire terminals) at base of intake manifold air heater relay. Polarity is not important.
4. Intake manifold air heater relay should click and ohmmeter should indicate a closed circuit between large terminals when battery voltage is applied to relay trigger wire terminals. Perform test on remaining intake manifold air heater relay.
5. If intake manifold air heater relay operation is not as specified, replace intake manifold air heater relay with bracket. Reconnect all electrical connectors and negative battery cables. If intake manifold air heater relay operation is as specified, but relay fails to operate when being controlled by the PCM, see appropriate TESTS W/CODES - DIESEL article for additional diagnostic information.

FUEL INJECTION PUMP TIMING

Improper fuel injection pump timing may result in low power, excessive smoke and poor fuel economy. For checking fuel injection pump timing, see CHECKING FUEL INJECTION PUMP TIMING under FUEL INJECTION PUMP TIMING in ADJUSTMENTS - DIESEL - DIESEL article.

THROTTLE LINKAGE ADJUSTMENT

Throttle linkage must be properly adjusted to ensure full throttle is obtained. For adjustment procedures, see LINKAGE ROD ADJUSTMENT under THROTTLE LINKAGE in ADJUSTMENTS - DIESEL article.

LOW IDLE SPEED

For checking and adjustment of low idle speed, see LOW IDLE SPEED under IDLE SPEED in ADJUSTMENTS - DIESEL article.

SUMMARY

If no faults were found while performing BASIC DIAGNOSTIC PROCEDURES, proceed to appropriate TESTS W/CODES - DIESEL article. If no diagnostic trouble codes are found in self-diagnostics, proceed to appropriate TESTS W/O CODES - DIESEL article for diagnosis by symptom (i.e., ROUGH IDLE, NO START, etc.) or intermittent diagnostic procedures.