Computers and Control Systems: Adjustments

1992 Chevrolet S10/T10 P/U 2WD V6-173 2.8LSECTION Adjustments
CONTROLLED IDLE SPEED CHECK
NOTE: Before performing this check, there should be no codes displayed, idle air control system has been checked and the ignition timing is correct.

1. Set parking brake and block drive wheels.
2. Connect a SCAN tool to the assembly line data link (ALDL) connect with tool in Open Mode.
3. START engine and bring it to normal operating temperature.
4. Check for correct state of PARK/NEUTRAL switch on SCAN tool.
5. Check specifications chart for controlled idle speed and IAC valve pintle position (counts).
6. If within specifications, the idle speed is being correctly controlled by the ECM.
7. If not within specifications, refer to DIAGNOSIS BY SYMPTOM/DIAGNOSIS AND TESTING PROCEDURES/ROUGH, UNSTABLE OR INCORRECT IDLE.

MINIMUM IDLE AIR RATE CHECK
Minimum Idle Air Rate is not adjustable for this engine.

CONTROLLED IDLE SPEED

Transmission Gear Idle Speed IAC Counts [1] OPEN/CLOSED Loop [2]

Man. N 800 5-20 OL

[1] Add 2 counts for engines with less than 500 miles. Add 1 count for every 1000 ft. above sea level.

[2] Let engine idle until proper fuel control status is reached (OPEN/CLOSED loop).

MINIMUM IDLE AIR RATE CHECK

Minimum Idle Air Rate is not adjustable for this engine.
RENDER: 1.0x

NO RELATED

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When to See a Mechanic

Stop DIY work and contact a certified mechanic immediately if any of the following apply:

  • You smell fuel, burning insulation, or see smoke.
  • Brakes feel soft, pull hard to one side, or make grinding noises.
  • The engine overheats, stalls repeatedly, or misfires under load.
  • You are missing required tools, torque specs, or safe lifting equipment.
  • You are not confident in the next step or safety outcome.