In order to complete this procedure, you will need a voltmeter and an EFI idle adjusting wiring harness (Special Service Tool 09842-4010) which is available at your Toyota dealer. If you do not have these tools, which are essential to this procedure, the car should be taken to a competent mechanic or dealership equipped for this procedure.
- Behind the battery on the left front fender apron is a service connector. Remove the rubber cap from the connector and connect the EFI idle adjusting wiring harness.
- Connect the positive lead of the voltmeter to the red wire of the wiring harness and then connect the negative lead to the black wire.
- Connect a tachometer as per the manufacturer's instructions.
- Warm up the oxygen sensor by running the engine at 2500 rpm for about two minutes. The needle of the voltmeter should be fluctuating at this time; if not, turn the idle mixture adjusting screw until it does.
- Set the idle speed to specifications (see Tune-Up Specifications chart) by turning the idle speed adjusting screw.
The idle speed should be set immediately after warm-up while the needle of the voltmeter is fluctuating.
- The idle adjustment procedure is now complete. Follow the remaining steps for the 4M-E and 5M-E engines.
- Remove the rubber cap from the idle adjusting connector and short both terminals of the connector with a wire
- While the connector is still shorted, run the engine at 2500 rpm for two more minutes.
- With the engine at idle and the connector still shorted, read and record the voltage shown on the voltmeter.
- Remove the short circuit wire from the connector and then race the engine to 2500 rpm once.
- Adust the idle mixture adjusting screw until the median of the indicated voltage range is the same as the reading taken in Step 8.
- Replug the idle mixture adjusting screw hole. Disconnect the tachometer, the voltmeter and the special wiring harness. Replace the rubber caps on the service connector and idle adjusting connector.
4M-E AND 5M-E ENGINES
- Fully open and then release the throttle valve.
- The throttle valve should return to the idle position in approximately 3.5 seconds.
- To adjust the return time, loosen the locknut and turn the adjusting bolt.