Engine Controls - Adjustments - Gasoline Dodge Dakota I

ENGINE MECHANICAL

Before performing any on-vehicle adjustments to fuel or ignition systems, ensure engine mechanical condition is okay.

VALVE CLEARANCE

Note. All engines use hydraulic lifters. No adjustments are required.

* PLEASE READ THIS FIRST *

Note. Always refer to Emission Control Information Label in engine compartment before service. If manual and emission label differ, always use emission label specifications. Basic timing is not adjustable on 3.3L.

ALL ENGINES EXCEPT 3.3L

1. Connect a suitable timing light to No. 1 cylinder. Refer to equipment manufacturer's instructions for proper connection. Turn selector switch to the appropriate cylinder position.
2. Start engine and warm to normal operating temperature. Connect tachometer and ensure idle RPM is within specification. See «CURB IDLE SPEED (RPM)»(/dodge/dakota/i-1987-1996/remont/adjustments/#engine-controls-adjustments-gasoline) table under IDLE SPEED & MIXTURE. Disconnect engine coolant sensor lead wire. Radiator fan should come on and CHECK ENGINE light should illuminate.
3. Check timing through timing window in bellhousing on 4-cylinder models or crankshaft pulley for other engines. See IGNITION TIMING table. DO NOT adjust timing if it is within 2 degrees of specification. If timing is incorrect, loosen distributor hold-down bolt and turn housing until specified timing is obtained.
4. Recheck timing after tightening distributor hold-down bolt. Reconnect coolant lead wire. Erase any fault codes. Recheck curb idle and adjust (if necessary). Remove diagnostic equipment.

IGNITION TIMING (Degrees BTDC @ RPM)

IDLE SPEED & MIXTURE

Note. Mixture is controlled by Single Board Engine Controller (SBEC). No adjustment is possible.

INTRODUCTION

Electronically fuel injected vehicles use an Automatic Idle Speed (AIS) motor or Idle Speed Control (ISC) actuator to regulate idle RPM. AIS or ISC is controlled by SBEC, which uses information received from various sensors to determine, among other things, idle speed. Curb idle speed is not adjustable. See appropriate G - TESTS W/ CODES article for diagnosis of incorrect idle speed.

IDLE RPM TEST

Note. Engine idle set RPM should be tested and recorded when vehicle is first brought into shop for testing. This will assist in diagnosing complaints of engine stalling, creeping and hard shifting on vehicles equipped with automatic transmissions.

1. Connect tachometer Red lead to coil negative (-) terminal and tachometer Black lead to a chassis ground.
2. Turn selector switch to appropriate cylinder position of engine being tested. Start engine and warm to normal operating temperature.
3. Turn tachometer RPM switch to 1000 RPM position.
4. With engine at normal operating temperature, momentarily open throttle and release to ensure linkage is not binding and throttle lever is fully against its stop.
5. Note engine RPM, and compare with specification. See the «CURB IDLE SPEED (RPM)»(/dodge/dakota/i-1987-1996/remont/adjustments/#engine-controls-adjustments-gasoline) table. If not within specification, see appropriate G - TESTS W/ CODES article

CURB IDLE SPEED (RPM)

MINIMUM AIRFLOW

Note. Minimum airflow testing procedures are provided for 2.5L, 3.0L, 3.3L & 3.9L engines equipped with Automatic Idle Speed (AIS) motor on throttle body.

1. Warm engine to normal operating temperature. Disconnect and plug heated air door vacuum hose. Connect timing light and tachometer. Disconnect engine coolant temperature sensor. Set basic timing to 10-14 degrees BTDC. Turn engine off. Reconnect coolant temperature sensor.
2. With engine off, disconnect hose from PCV valve, and plug PCV valve nipple. Disconnect idle purge hose from vacuum harness "T". (Scheme 1) Attach Air Metering Fitting (6457) to manifold-mounted idle purge hose. Orifice size is.125" (3 mm). Connect Diagnostic Readout Box II (DRB-II) to vehicle.
3. Start engine. Let engine idle for at least one minute. Using DRB-II, access MINIMUM AIRFLOW IDLE SPEED. When this mode is accessed, AIS motor will fully close, spark advance will fix, fuel delivery will not change and engine RPM will be displayed on DRB-II.
4. Check minimum airflow. See MINIMUM AIRFLOW IDLE SPEED table. If minimum airflow idle speed is not within specification, replace throttle body.

Scheme 1

MINIMUM AIRFLOW IDLE SPEED

THROTTLE POSITION SENSOR

Note. Throttle Position Sensor (TPS) is not adjustable. The following procedures may be used to check TPS calibration.

1. Turn ignition switch to "ON" position. DO NOT start engine. Measure voltage at center terminal of TPS, with throttle valve fully closed against stop. Voltage should be 1.5 volts or less. If voltage is not 1.5 volts or less, replace TPS.
2. Slowly open throttle valve to wide open throttle. TPS voltage should gradually increase to at least 3.4 volts. If voltage does not gradually increase to at least 3.4 volts, replace TPS.

See also:
• CURB IDLE SPEED (RPM)