Engine Adjustments - 4.0l Engine Jeep Grand Cherokee ZJ рестайлинг

INTRODUCTION

Note. Introduction information not applicable.

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.

IGNITION TIMING

Note. Ignition timing is controlled by Powertrain Control Module (PCM). No adjustment is required.

Ignition timing is nonadjustable. DO NOT attempt to adjust ignition timing by rotating distributor. If distributor is rotated or replaced, fuel system synchronization will be changed. To synchronize fuel system, see FUEL SYSTEM SYNCHRONIZATION under FUEL SYSTEM.

FUEL SYSTEM SYNCHRONIZATION

Note. Fuel system synchronization is controlled by position of the distributor. Rotating distributor WILL NOT change ignition timing, but will change fuel system synchronization. Fuel system synchronization should be checked anytime distributor is removed or rotated.

1. Connect scan tool to Data Link Connector (DLC), located below driver's side of instrument panel, near steering column. Select SET SYNC from scan tool menu. Start engine and go to next step.
2. If scan tool displays IN RANGE along with 0°, this indicates correct distributor location. The degree reading displayed on scan tool indicates the fuel synchronization, not ignition timing.
3. If scan tool display is correct, turn engine off. Remove scan tool. If scan tool does not display IN RANGE along with 0°, go to next step.
4. If scan tool displays a plus (+) or minus (-) sign next to the degree number, and/or the degree number displayed is not zero, loosen but DO NOT remove distributor hold-down bolt.
5. Rotate distributor until scan tool displays IN RANGE. Continue to rotate distributor until a reading as close as possible to 0° is obtained. Tighten distributor hold-down bolt to 16.7 ft. lbs. (22.5 N.m). Shut engine off. Remove scan tool.

IDLE SPEED & MIXTURE

Note. Idle speed and mixture are controlled by Powertrain Control Module (PCM). No adjustment is required.

PCM controls Idle Air Control (IAC) motor for proper idle speed.

THROTTLE POSITION SENSOR

Note. Throttle Position (TP) sensor is controlled by Powertrain Control Module (PCM). No adjustment is required.