Engine Controls - Adjustments Buick LeSabre VII

ENGINE MECHANICAL

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

VALVE CLEARANCE

Note. All models use hydraulic lifters. Adjustments are not required.

IGNITION TIMING

Note. Procedures for timing adjustment are for engines equipped with HEI-EST distributors only. Other engines are equipped with C(3)I, DIS, IDI or Opti-Spark ignition system. Timing on these systems is not adjustable.

IDLE SPEED & MIXTURE

Note. Idle mixture is controlled by Powertrain Control Module (PCM). Adjustment is not possible.

IDLE SPEED

Note. Idle speed is controlled by PCM and is not adjustable. Slight fluctuations in idle speed are considered normal. Start and run engine for at least 7 minutes to establish PCM control of idle.

Note. Incorrect idle speeds are normally caused by dirty throttle plate or vacuum leaks. Ensure all vacuum components are functioning properly.

1. Idle speed is PCM-controlled. Resetting of IAC valve pintle is the only adjustment that can be performed. To reset IAC valve pintle position, turn ignition off.
2. Disconnect negative battery terminal for 10 seconds to clear PCM memory. Reconnect negative battery terminal. Turn ignition on for 5 seconds, then off for 10 seconds. Start engine, and check for proper idle operation. Repeat step 1) if proper idle operation is not obtained.

IDLE MIXTURE

Note. Idle mixture is controlled by Powertrain Control Module (PCM). Adjustment is not possible.

THROTTLE POSITION SENSOR

Note. TP sensor is not adjustable. For further testing procedures, refer to appropriate TESTS W/CODES or SYSTEM/COMPONENT TESTS article in this section.

TP SENSOR ADJUSTMENT VOLTAGE

See also:
• COMPUTER RELEARN PROCEDURES
• TESTS W/CODES
• SYSTEM/COMPONENT TESTS