Early Version With Two Throttle Switches

Throttle valve/deceleration/idle switch, checking

Note:
This switch supplies control unit with information that throttle valve is closed.
If engine is above 1500 rpm with the throttle closed, fuel will be shut off to the injectors.
At idle speed, this switch signals control unit to regulate amount of fuel injected

CAUTION: Do not connect test light to throttle valve switch connectors if control unit is connected





First Check, Throttle Valve Switch
- Disconnect throttle valve switch connectors
- Attach ohmmeter to switch 1
Throttle valve closed; switch turned ON = 0 ohms
Throttle valve open slightly; switch turned OFF = infinite ohms

Second Check, Wiring And Control Unit
- Run engine at idle speed for a short time
- Stop engine and turn ignition ON
- Pull off connectors from both throttle valve switches
- Check voltage between connectors of throttle valve idle switch
Voltage should be approx. 5 volts
If NO, control unit is defective or break in wiring

Third Check, Deceleration

Test Conditions
Result of first and second check must be OK
Throttle valve switch connectors connected
Temperature at temperature sensor II must be minimum 80°C (140°F) and resistance below 550 ohms

Work Procedure
- Start engine
- Hold throttle valve switch closed by hand and accelerate slowly
Engine speed must fluctuate (surges)
If NO, replace control unit

Throttle Valve/Deceleration/Idle Switch, Adjusting
Throttle valve closed
- Adjust screw 2 so that switch just closes
- From this position turn adjusting screw exactly one turn farther in
- Secure adjusting screw with sealant

Note: Correct adjustment is very important. If switch is misadjusted engine may surge or cut-out during acceleration