Engine Controls - Tests W/o Codes Dodge Spirit I

INTRODUCTION

Before attempting to diagnose symptoms or intermittent faults, ensure steps in BASIC TESTING and TESTS W/CODES (if applicable) articles have been performed. Use this article to diagnose driveability problems that exist when a hard fault code is not present.

Symptom checks are intended to direct the technician to malfunctioning component(s) so further diagnosis may be performed. A symptom should lead to further testing of specific components or systems, or verification of adjustment specifications.

Use intermittent test procedures to locate intermittent driveability problems that do not occur when the vehicle is being tested. These problems may cause a noticeable driveability problem or cause the malfunction warning light to illuminate on some vehicles.

It is also possible that certain driveability concerns have been rectified by the manufacturer through substitution of a revised calibration chip or computer control unit. Check with manufacturer for latest information on updated chips and control units.

Note. For specific testing procedures, see Appropriate I - SYS/COMP TESTS article. For specifications, see Appropriate C -SPECIFICATIONS 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 appropriate BASIC TESTING and TESTS W/CODES articles were performed before diagnosing a symptom. Symptoms available for diagnosis include

1. No Start - Cold Engine
2. No Start - Warm Engine
3. Starts But Stalls
4. Hard To Start - Cold Engine
5. Erratic Idle - Warm-Up
6. Backfiring
7. Incorrect Idle Speed
8. Hesitation - Acceleration
9. Hesitation - Coasting
10. Knocking
11. Engine Misfire - All Conditions
12. Insufficient Engine Power
13. Poor Fuel Economy
14. Excessive HC and NOx

NO START - COLD ENGINE

1. Ensure battery is fully charged
2. Check spark plugs
3. Check fuel pump fuse(s)
4. Ensure ignition timing and fuel pressure are correct
5. Check fuel injectors
6. Ensure timing belt/chain has not jumped
7. Ensure ignition coil resistance is correct
8. Ensure rotor, distributor and plug wires are okay
9. Check ignition control unit
10. Check coolant temperature sensor and connector
11. Check throttle position sensor and connector
12. Check engine speed sensor
13. Check airflow sensor

NO START - WARM ENGINE

1. Ensure fuel pressure is correct
2. Check for gasoline in oil
3. Ensure fuel injectors are not leaking
4. Check ignition and sensor wires for proper connection
5. Ensure spark plugs are not fouled
6. Check ignition and coil circuit
7. Check engine speed sensor
8. Check throttle position sensor and connector

STARTS BUT STALLS

1. Check coolant temperature sensor
2. Check ignition and sensor wires for proper connection
3. Check fuel injectors
4. Check throttle position sensor and connector
5. Check engine speed sensor

HARD TO START - COLD ENGINE

1. Check spark plugs
2. Check distributor (if applicable)
3. Ensure fuel pressure is correct
4. Check ignition timing
5. Check throttle position sensor and connector

ERRATIC IDLE - WARM-UP

1. Check throttle position sensor and connection
2. Check coolant temperature sensor and connection
3. Check air temperature sensor (turbo only)
4. Ensure spark plugs are not fouled
5. Check ignition and sensor wires for proper connection
6. Check distributor (if applicable)
7. Check ignition and coil circuit
8. Check intake system
9. Check engine speed sensor
10. Check throttle position sensor and connector
11. Check MAP sensor

BACKFIRING

1. Ensure ignition timing is correct
2. Ensure timing belt/chain has not jumped
3. Check distributor (if applicable)
4. Check for gasoline in oil
5. Ensure fuel injectors are not leaking
6. Check spark plugs
7. Check ignition and coil circuit
8. Check engine speed sensor
9. Check throttle switch and connector
10. Check exhaust system

INCORRECT IDLE SPEED

1. Check fuel injectors
2. Check intake system for leaks
3. Check coolant temperature sensor
4. Check throttle position sensor and connector
5. Check distributor (if applicable)

HESITATION - ACCELERATION

1. Check ignition and sensor wires for proper connection
2. Check distributor cap for moisture or carbon tracking (if applicable)
3. Ensure spark plug wires are okay
4. Ensure spark plugs are not fouled
5. Check MAP sensor
6. Check throttle position sensor and connector
7. Check ignition and coil circuit
8. Check engine speed sensor

HESITATION - COASTING

1. Check fuel injectors
2. Check ignition and sensor wires for proper connection
3. Check throttle switch and connector
4. Check engine speed sensor
5. Check for gasoline in oil

KNOCKING

1. Check ignition and coil circuit
2. Ensure spark plugs fire
3. Check knock sensor (if applicable)
4. Check throttle position sensor and connector
5. Check engine speed sensor
6. Check MAP sensor

ENGINE MISFIRE - ALL CONDITIONS

1. Check fuel injectors
2. Check ignition and sensor wires for proper connection
3. Check ignition and coil circuit
4. Check for gasoline in oil
5. Check intake and exhaust system
6. Check throttle position sensor and connector
7. Check for vacuum leaks
8. Check engine speed sensor
9. Check MAP sensor

INSUFFICIENT ENGINE POWER

1. Check fuel injectors
2. Ensure fuel pressure is correct
3. Check airflow sensor
4. Check for restricted exhaust
5. Check coolant temperature sensor
6. Check air temperature sensor (turbo only)
7. Check throttle position sensor and connector
8. Check ignition and coil circuit
9. Check MAP sensor
10. Check engine speed sensor
11. Check intake and exhaust system

POOR FUEL ECONOMY

1. Check for leaky fuel injectors
2. Ensure spark plugs are not fouled
3. Check for faulty oxygen sensor
4. Check throttle switch and connector
5. Check for poor wire connections and fouled spark plugs
6. Check engine speed sensor
7. Check for gasoline in oil
8. Check MAP sensor

EXCESSIVE HC AND NOx

1. Check for gasoline in oil
2. Check for leaky fuel injectors
3. Check for faulty oxygen sensor
4. Check ignition and sensor wires for poor connection
5. Check engine speed sensor
6. Check throttle position sensor and connector
7. Check for vacuum leaks

INTERMITTENT PROBLEM DIAGNOSIS

Intermittent fault testing requires duplicating circuit or component failure to identify the problem. These procedures may lead to the computer setting a fault code (on some systems) which may help in diagnosis.

If problem vehicle does not produce fault codes, monitor voltage or resistance values using a 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 change in DVOM while performing test procedures will indicate area of fault.

TEST PROCEDURES

Intermittent Simulation

To reproduce the conditions creating an intermittent fault, use the 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 self-diagnostic codes. Use test results to identify a faulty component or circuit.