Trionic T5.2

The Trionic T5.2 was introduced in Saab 9000 year 1993 and was discontinued the same year. Its Engine Control Unit is based on a Motorola 32 bit CPU. This engine management system was used on the "long block" engines. Its was superseded by Trionic T5.5 engine management system. The Trionic T5.2 uses a Mecel patented ion current measurement to decide which cylinder that was in compression phase and just have ignited the air/fuel mixture, this ion current measurement can also conclude whether there has been pre detonation or knocking when the cylinder has fired. Finally the ion current measurement can register misfire with outstanding accuracy. The ion current measurement is thus used to synchronise the ignition. Trionic T5.2 uses a MAP (Manifold Absolute Pressure) sensor to, indirectly, measure the weight of the air that has been drawn/forced into the cylinders. It uses a simple slotted aperture disc to measure the TDC for cylinders 1 & 4 and the engine's RPM.