911 Turbo F6-3299cc 3.3L SOHC Turbo (1992)
Turbocharger Control Module: Description and Operation
Control Units
PURPOSE
Turbo control unit includes the following basic functions:
1. Actuating fuel pumps
2. Switching supply voltage of oxygen sensor closed-loop control and acceleration enrichment
3. Switching supply voltage of ignition system
4. Switching ground for oxygen sensor heater
5. Switchover of oxygen sensor closed-loop control to open-loop control.
OPERATION
Prerequisites for function 1:
^
Terminal 15 ON and engine speed signal from EZ control unit or terminal 50 present
^
Engine speed below 6750 rpm
^
Boost pressure cutout switch closed
Prerequisites for function 2:
^
Terminal 15 ON
^
Engine speed below 3000 rpm
Prerequisites for function 3:
^
Terminal 15 ON
Prerequisites for function 4:
^
Only if oxygen sensor closed-loop control is activated
Prerequisites for function 55:
^
If oxygen sensor closed-loop control is not activated.
Turbo control unit also handles:
^
Voltage supply to:
- Control pressure regulator
- Auxiliary air regulator
- Frequency valve
- Oxygen sensor heater
^
Safety circuit for fuel pumps
^
Boost pressure safety circuit
^
Ignition delay relay
