Throttle Position Sensor: Adjustments

1986 Chevrolet Caprice Wagon V8-305 5.0LSECTION Adjustments

Verify that minimum idle is at specified value.

Make all checks/adjustments with engine at operating temperature.

Carbureted Models: Remove aluminum plug covering the adjustment screw. Remove the screw and connect a digital voltmeter to black wire (-) and either of the other two colored wires (+). If voltage is approximately 5 volts, this is the reference voltage source. Connect DVOM to the other wire in this case. Apply thread locking compound to the screw and with ignition on and engine not running (as applies), quickly adjust screw to obtain specified voltage at indicated condition.

Fuel Injected Models: Disconnect harness connector from TPS. Using three six-inch jumper wires, reconnect harness to TPS. With ignition on and engine not running (as applies), connect a digital voltmeter to black wire (-) and either of the other two colored wires (+). If voltage is approximately 5 volts, this is the reference voltage source. Connect DVOM to the other wire in this case. Check reading against specified value. If TPS is adjustable, loosen the unit retaining screws and rotate the unit to reach specified value.



RENDER: 1.0x

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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.