Test Point 5 - Ignition System
TEST POINT 5 - DME 944Ignition System
a) Secondary Image
Adjust secondary image on oscilloscope. Connect tester leads to supplier's instructions.
Note: If a defect is displayed for alt cylinders, it is in the primary or secondary circuit between the ignition coil and distributor. If a defect is displayed for only one cylinder, it is after the distributor rotor.
Primary resistance: term. 1 + 15 = 0.4 - 0.6 ohm
Secondary resistance: term. 1 + 4 = 5.0 - 7.2 kohm
b) Spark Plug Connectors
Suppression resistor: 3 kohm
Visual inspection for damage or burning.
c) Distributor
Distributor rotor, distributor cap: suppression resistor each 1 kohm. Visual inspection for damage, dirt and wrong installed position.
d) Ignition Timing Check
Ignition timing is not adjusted.
Only the ignition timing at idle speed is checked.
Engine at operating temperature.
Test Value:
Ignition timing at 840 ± 40 rpm = 10° ± 3° before TDC
USA/unleaded engines: 5° ± 3° before TDC
Control value at 3200 rpm and bridged test connections B and C (full load contact) = ign. timing: 23 ± 3° before TDC
The speed/ignition timing test can be made by using the TDC sensor system in conjunction with an engine tester, which is suitable for this type of testing.