Ignition system — general information (Chevrolet Lumina 1)

Engines with a displacement of 3.1 liters are equipped with a high - power ignition system (HEI), while engines with a displacement of 3.8 liters are equipped with a direct ignition system (without distributor) ignition (DIS).

HEI High Power Ignition System (for 3.1L engines)

HEI equipped vehicles use a special HEI ignition distributor with an Electronic Spark Plug (EST) device. The HEI distributors discussed in this manual have a separate ignition coil.

All changes to the ignition timing in the HEI/EST distributor are performed by the Electronic Control Module (ECM), which continuously reads data from various sensors installed on the engine, calculates the required ignition timing and commands the distributor to make the appropriate changes to the ignition timing. Neither vacuum nor mechanical ignition timing regulators are used here.

Electronic ignition control (ESC)

The 3.1L and 3.8L engines are equipped with an Electronic Spark Control (ESC) system, which uses a knock sensor in conjunction with the ECM/PCM to regulate ignition timing, allowing the engine to achieve maximum ignition advance without causing detonation. This improves the vehicle's performance and reduces fuel consumption.

Spark plug high voltage wires

The wires used in the HEI system are graphite impregnated conductive cords enclosed in an 8mm diameter rubber sheath with an outer silicone insulation. This type of conductor can withstand high temperatures well and is an excellent insulator for the high voltage generated by the HEI unit.

Caution! The HE system generates extremely high voltage, so when performing any work on components related to the ignition system, all safety precautions must be taken. This applies not only to the ignition distributor, control unit and high-voltage ignition wires, but also to ignition-related components such as spark plug contacts, tachometer and diagnostic equipment.

Direct Ignition System DIS

In this distributorless system, the ignition timing is controlled by the electronic PCM unit. There are no moving parts in this system, which eliminates the need for adjustment. The ignition coils installed in it are cooled more efficiently during operation and the system itself requires almost no maintenance.

Direct ignition systems use a so-called "extra spark plug" ignition distribution method. Each pair of cylinders has one ignition coil (1-4, 2-5, 3-6), as a result, a spark appears simultaneously in the cylinder in the compression stroke and in the cylinder in which the piston is in the exhaust stroke. Since there is very little voltage drop across the spark gap in a cylinder on the exhaust stroke, almost all of the voltage is used to spark the cylinder on the compression stroke.

The DIS system consists of three coils, an ignition unit, and a crankshaft position sensor (which uses the double Hall effect), crankshaft vibration damper with crankshaft position sensor interrupter rings installed on its rear tailpiece, camshaft position sensor, ignition wire and PCM control unit.

In conventional ignition coils, one end of the secondary winding is connected to "ground". In direct ignition coils, neither end of the secondary winding is connected to "ground"; on the contrary, both its ends are directly connected to spark plugs in opposite cylinders.

The dual Hall effect magnetic crankshaft position sensors are mounted on an aluminum mounting bracket that bolts to the front valve cover. The breaker points on the crankshaft damper interrupt the control voltage, causing an "ON-OFF-ON-OFF" reaction" ("ON-OFF-ON-OFF") etc., reminiscent of the sequence of operation of contacts in conventional ignition systems. The DIS system, like conventional ignition timing systems, is equipped with an Electronic Spark Timing Control (EST) unit and control circuit wires from the PCM unit.