Throttle Position Sensor: Adjustments

Throttle Position Sensor Adjustment:

The throttle position sensor is the only adjustable component that is part of the computer controlled systems. The following procedure should be used for adjustment.

TPS ASSEMBLY ADJUSTMENT

NOTE: Before adjusting, check for proper idle and "Fast Idle" adjustment.

1. Set parking brake with transmission in "Park" (A/T) or "Neutral" (M/T), and block drive wheels.

2. Start engine and run until at normal operating temperature with choke open. "Scan" dwell and wait until dwell is varying.

NOTE: Be sure all accessories are turned "OFF" and wait until electric cooling fan stops.


3. Connect digital voltmeter between ECM Terminals "8" and "22."

4. "Scan" rpm.

5. Voltage should change from 0 volts to 5.0 volts when engine speed reaches 1800 rpm (A/T) or 1600 rpm (M/T).

6. If voltage does not change adjust TPS by rotating assembly.

7. Turn "ON" A/C. Voltage should remain at 0 volts and throttle should open slightly.

8. If voltage increases to 5V with A/C "ON," recheck fast idle adjustment, fast idle should not excede 1800 rpm (A/T) or 1600 rpm (M/T). If fast idle is adjusted correctly, readjust TPS assembly until voltage falls to zero.