Fuel Injection

Fuel injection--in the Saab Trionic system is sequential, which means that fuel is injected according to the engine's firing order.

Injection duration-is calculated by the control module, mainly on the basis of the following information:

- pressure in the intake manifold
- intake air temperature
- engine rpm
- engine coolant temperature
- oxygen content of the exhaust gases
- knocking, if any
- throttle position



Pre-injection--Turning the ignition switch to the Drive position causes the main and fuel pump relays to operate. At the same time, all the injectors open and squirt a small amount of fuel onto the inlet valves. The length of time the injectors remain open is determined by the engine coolant temperature. The purpose of this is to achieve shorter starting times.