COLD (FAST) IDLE SPEED ADJUSTMENT
No fast idle adjustments are possible on fuel injected models.
IDLE MIXTURE ADJUSTMENT
Note. No idle mixture adjustments are possible on any models. See appropriate G - "Engine Type" TESTS W/CODES article for diagnosis of incorrect idle mixture.
THROTTLE POSITION SENSOR (TPS) ADJUSTMENT
Note. Two types of TPS are used on EEC-IV system. "Level C" type is adjustable and "Level D/RD" type is nonadjustable. Throttle position sensors without slotted mounting holes are not adjustable. If voltage reading on nonadjustable TPS is not .9-1.1 volts at idle, and greater than 4 volts at wide open throttle, replace throttle position sensor.
- To adjust "Level C" type sensors, use EEC-IV Breakout Box (Rotunda T83L-50-EEC-IV). Connect digital voltmeter and set to 20-volt scale. Connect positive voltmeter lead to pin No. 47 and negative voltmeter lead to pin No. 46.
- Turn ignition on. Loosen TPS hold-down screws. Rotate TPS until voltmeter reading is 1.0 volt. Tighten hold-down screws. Move throttle to Wide Open Throttle (WOT) position. Voltmeter should read 1.0 volt at idle, at least 4.0 volts at WOT and then return to 1.0 volt at idle.
- If voltage is not as specified, perform EEC-IV QUICK TEST in G - "Engine Type" TESTS W/CODES article.