Quote:
Originally Posted by Oregon 911
How do I diagnose my ignition problem if it’s the CD box?
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- First check the inductive coil within the distributor if its not flawed: Disconnect the green wire plugs from the CDI and use an ohm meter where on both terminals of the green wire it should read about 600 ohms
- After that (if you don't have an oscilloscope) and with still the green wire disconnected from the CDI, let someone just crank the engine by starting about 2-3 seconds. Here a DMM should read on the terminals of the green wire about 5 volts and more, depending on the rpm. Actually its not a flat voltage output but an zero crossing inductive signal from negative to positive voltage.
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www.911-hkz.de)
- Finally with re connected green wire to the CDI unit, check with a timing light for a given spark on the ignition wire.
This test only lets you know if the inductive coil is ok and the CDI is "working".
For a detailed CDI test you'll need an oscilloscope with a high voltage probe for testing the high voltage output of the CDI at all revs at the "A" terminal of your ignition coil. Caution: High voltage here!
(Image from
www.911-hkz.de)