Test Point 5 - Ignition System
TEST POINT 5Ignition System
1. Adjust secondary image on oscilloscope: term. 1 and term. 15, trigger clip on cylinder no.1.
Note: If a defect is displayed for all cylinders, it will be in the primary or secondary circuit from the ignition coil to the distributor rotor. If a defect is displayed for only one cylinder. it will be after the distributor rotor.
2. Check distributor cap for damage, burnt spots and dirt. Retaining hooks must engage firmly when installing.
3. Check distributor rotor.
Shielded resistance: 1 k-ohm.
Check visually for tight fit, damage and dirt.
4. Check spark plug caps and leads for damage or traces of burning.
Shielded resistance: 3 k-ohm.
5. Check ignition coil.
Primary resistance: term. 1 against 15 = 0.4 - 0.6 ohm.
Secondary resistance: term. 1 against 4 = 5 - 7.2 k-ohms.
Check visually for damage or burnt spots.
Note: Avoid checking the ignition system via the spark gap by pulling off the spark plug caps. This could cause destruction of the ignition coil and control unit.
6. Check ignition timing at idle speed and with engine having operating temperature.
Ignition timing at 800 + 50 rpm = 5 to 15° before TDC.