Engine Controls - Tests W/o Codes - Diesel Engine Dodge Pickup R2500

INTRODUCTION

Before using this article, perform steps in appropriate BASIC TESTING - DIESEL and TESTS W/CODES - JEEP, TRUCKS & RWD VANS articles. Use this article to diagnose driveability problems existing when a hard Diagnostic Trouble Code (DTC) is not present.

Note. Some driveability problems may have been corrected by manufacturer with a revised Powertrain Control Module (PCM). Check with manufacturer for latest PCM application.

Symptom checks direct the technician to malfunctioning component(s) for further diagnosis. A symptom should lead to a specific component, system test or adjustment.

Use intermittent test procedures to locate driveability problems that DO NOT occur when the vehicle is being tested. These test procedures should also be used if an intermittent (soft) DTC was present, but no problem is found during self-diagnostic testing.

Note. For specific testing procedures, see TESTS W/CODES - JEEP, TRUCKS & RWD VANS article. For specifications, see ADJUSTMENTS - DIESEL or SPECIFICATIONS - TRUCKS & VANS article.

SYMPTOM DIAGNOSIS

Symptom checks cannot be used properly unless the problem occurs while the vehicle is being tested. To reduce diagnostic time, ensure steps in BASIC TESTING - DIESEL and TESTS W/CODES - JEEP, TRUCKS & RWD VANS articles were performed before diagnosing a symptom. Symptoms available for diagnosis are as follows

1. Engine Hard To Start
2. Engine Surges At Idle
3. Engine Has Rough Idle When Warm
4. Engine Misfiring Under Load
5. Engine Has Low Power
6. Excessive Fuel Consumption
7. Engine Will Not Shut Off
8. Black Exhaust Smoke
9. White Or Blue Exhaust Smoke
10. Incorrect Idle Speed
11. Engine Speed Will Not Increase
12. Fuel Injection Pump Runs Hot

ENGINE HARD TO START

1. Air in fuel system.
2. Clogged fuel filter.
3. Poor fuel quality.
4. Electrical fuel shutdown solenoid and/or relay not operating.
5. Fuel tank empty or fuel tank vent blocked.
6. Restricted, blocked or leaking fuel injection or supply lines.
7. Incorrect timing or defective fuel injection pump.
8. Malfunctioning intake air heater system.
9. Low or uneven engine compression.
10. Injection sequence does not correspond with firing order.
11. Restricted or damaged air filter.
12. Wax build-up in fuel filter (cold weather).

ENGINE SURGES AT IDLE

1. Air in fuel system.
2. Fuel level low or fuel tank vent blocked.
3. Low idle speed.
4. Incorrect timing or defective fuel injection pump.

ENGINE HAS ROUGH IDLE WHEN WARM

1. Air in fuel system.
2. Poor fuel quality.
3. Low idle speed.
4. Leaking high or low pressure fuel line.
5. Loose injector pump rear support bracket.
6. Restricted or damaged fuel injector.
7. Injection sequence does not correspond with firing order.
8. Low or uneven engine compression.
9. Incorrect timing or defective fuel injection pump.

ENGINE MISFIRING UNDER LOAD

1. Air in fuel system.
2. Poor fuel quality.
3. Fuel level low or fuel tank vent blocked.
4. Clogged or defective fuel filter.
5. Restricted, blocked or leaking fuel injection or supply lines.
6. Incorrect timing or defective fuel injection pump.
7. Restricted or damaged fuel injector.

ENGINE HAS LOW POWER

1. Air in fuel system.
2. Poor fuel quality.
3. Fuel level low or fuel tank vent blocked.
4. Fuel control lever not obtaining full throttle.
5. Clogged or defective fuel filter.
6. Clogged or leaking intercooler.
7. Restricted exhaust system.
8. Restricted, blocked or leaking fuel injection or supply lines.
9. Improper fuel line banjo bolts at fuel injection pump.
10. Incorrect timing or defective fuel injection pump.
11. Restricted or damaged fuel injector.
12. Restricted or damaged air filter.
13. Turbocharger boost control line broken or leaking.
14. Low manifold pressure.
15. Injection sequence does not correspond with firing order.
16. Low or uneven engine compression.

EXCESSIVE FUEL CONSUMPTION

1. Poor fuel quality.
2. Incorrect timing or defective fuel injection pump.
3. Damaged fuel injector.
4. Restricted or damaged air filter.
5. Injection sequence does not correspond with firing order.
6. Clogged or leaking intercooler.
7. Improper idle speed.

ENGINE WILL NOT SHUT OFF

1. Fuel shutdown solenoid not operating.
2. Fuel shutdown solenoid electrical circuit faulty.

BLACK EXHAUST SMOKE

1. Air in fuel system.
2. Poor fuel quality.
3. Clogged or leaking intercooler.
4. Restricted, blocked or leaking fuel injection or supply lines.
5. Incorrect timing or defective fuel injection pump.
6. Restricted or damaged fuel injector.
7. Restricted or damaged air filter.
8. Low manifold pressure.
9. Injection sequence does not correspond with firing order.
10. Low or uneven engine compression.

WHITE OR BLUE EXHAUST SMOKE

1. Air in fuel system.
2. Poor fuel quality.
3. Clogged or defective fuel filter.
4. Improper fuel line banjo bolts at fuel injection pump.
5. Restricted or blocked fuel injection or supply lines.
6. Improper fuel line banjo bolts at fuel injection pump.
7. Incorrect timing or defective fuel injection pump.
8. Wax build-up in fuel filter (cold weather).

INCORRECT IDLE SPEED

1. Improper idle speed adjustment.
2. Defective fuel injection pump.

ENGINE SPEED WILL NOT INCREASE

1. Air in fuel system.
2. Poor fuel quality.
3. Fuel tank empty or fuel tank vent blocked.
4. Fuel control lever not obtaining full throttle.
5. Clogged or defective fuel filter.
6. Clogged or leaking intercooler.
7. Restricted, blocked or leaking fuel injection or lines.
8. Incorrect timing or defective fuel injection pump.
9. Improper fuel line banjo bolts at fuel injection pump.
10. Low or uneven engine compression.
11. Wax build-up in fuel filter (cold weather).

FUEL INJECTION PUMP RUNS HOT

1. Fuel injection pump return line restricted.
2. Fuel injection pump oil supply or return line clogged.

INTERMITTENT PROBLEM DIAGNOSIS

Intermittent fault testing requires duplicating circuit or component failure to identify problem. These procedures may lead to PCM setting a Diagnostic Trouble Code (DTC) which may help in diagnosis.

If problem vehicle does not produce DTCs, monitor voltage or resistance values using a Digital Volt-Ohmmeter (DVOM) while attempting to reproduce conditions causing intermittent fault. A status change on DVOM indicates a fault has been located.

Use a DVOM to pinpoint faults. When monitoring voltage, ensure ignition switch is in ON position or engine is running. Ensure ignition switch is in OFF position or negative battery cable is disconnected when monitoring circuit resistance. Status changes on DVOM during test procedures indicate area of fault.

Intermittent Simulation

To reproduce conditions creating an intermittent fault, use following methods

1. Lightly vibrate component.
2. Heat component.
3. Wiggle or bend wiring harness.
4. Spray component with water.
5. Remove/apply vacuum source.

Monitor circuit/component voltage or resistance while simulating intermittent. If engine is running, monitor for diagnostic trouble codes. Use test results to identify a faulty component or circuit.