Part 3 of 3

Chart A-3 - Engine Cranks But Will Not Run (Part 3 of 3):

CRANKS BUT WILL NOT RUN:

CIRCUIT DESCRIPTION
If the "Scan" tool did not indicate a cranking RPM and there is no spark present at the plugs, the problem lies in the Direct Ignition System (DIS) or the power and ground supplies to the module. The magnetic crank sensor is used to determine engine crankshaft position much the same way as the pickup coil did in distributor type systems. The sensor is mounted in the block near a seven slot wheel on the crank shaft. The rotation of the wheel creates a flux change in the sensor which produces a voltage signal. The ignition module then processes this signal and creates the reference pulses needed by the Electronic Control Module (ECM) and the signal triggers the correct coil at the correct time.

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

11. This test will determine if the 12 volt supply and a good ground is available at the ignition module.

12. Tests for continuity of CKT 439 to the ignition module. If test light does not light but the "Service Engine Soon" (SES) light is "ON" with ignition "ON," repair open in CKT 439 between DIS ignition module and splice.

13. Checks for continuity of the crank sensor and connections.

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