C-4D3 ~ No Spark

DIS Circuit:

C-4D-1 DIS "No Spark" Diagnostic Chart:

CIRCUIT DESCRIPTION:
The Direct Ignition System (DIS) uses a waste spark method of distribution. In this type of system, the ignition module triggers a dual coil, resulting in both connected spark plugs firing at the same time. One cylinder is on its compression stroke at the same time that the other is on the exhaust stroke, resulting in - a lower energy requirement to fire the spark plug in the cylinder on its exhaust stroke. The leaves the remainder of the high voltage to be used to fire the spark plug which is in the cylinder on its compression stroke.


TEST DESCRIPTION:
Numbers below refer to the circled numbers on the diagnostic chart.

1. This test check to see if spark is present on one or more spark plug wires.

2. Check for continuity of the cam sensor and connection.

3. Check for continuity of the cam sensor and connection.

4. Voltage will vary in this test depending on cranking speed of the engine. The voltage will vary from about 500 mv at very slow cranking speeds to about 100 mv at high speed.


DIAGNOSTIC AIDS:
An intermittent may be caused by a poor connection, rubbed through wire insulation or a wire broken - inside the insulation. Inspect the cam sensor and DIS module harness connectors for backed out terminals, improper mating, broken locks, improperly formed or damaged terminals, poor terminal to wire connection and damaged harness.