LEMON Manuals: Even more car manuals for everyone: 1960-2025
Home >> Saturn >> 1993 >> SC1 Automatic >> Repair and Diagnosis >> Engine Performance >> Theory and Operation >> Engine Controls - Theory & Operation >> Computerized Engine Controls >> Input Devices >> 2.0L, 2.2L, 3.1L and 3.4L
April 5, 2026: LEMON Manuals is launched! Read the announcement.

2.0L, 2.2L, 3.1L and 3.4L

The Direct Ignition System (DIS) and 2.3L Integrated Direct Ignition (IDI) system crankshaft position sensor protrudes through side of engine block to within .05" (1.3 mm) of an internally-mounted crankshaft reluctor ring. The reluctor ring is a special trigger wheel cast into the crankshaft. As crankshaft rotates, 7 notches in the reluctor ring change the magnetic field at the tip of the position sensor. This creates an induced AC voltage signal in the sensor windings, resulting in reference signals which are sent to ECM by ignition module. This allows ECM to compute crankshaft position and RPM and fire appropriate ignition coil at the proper time.

Vehicles equipped with HEI-EST distributor systems use the RPM reference signal from the ignition module in the distributor for a crankshaft position signal. TDC intake and TDC exhaust are not differentiated; differentiation is not necessary on non-sequential fuel injected engines. Signal is used to trigger fuel injectors. For additional information, see COMPUTER CONTROLLED COIL IGNITION (C(3)I) and DIRECT IGNITION SYSTEM (DIS) & INTEGRATED DIRECT IGNITION (IDI) SYSTEM under IGNITION SYSTEM  .