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jjrowe jjrowe is offline
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Join Date: May 2003
Location: San Diego, CA
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No Spark - CDI Testing

After putting my motor back together (with a rebuilt wire harness) I have no spark. The CD box is humming. So I have done the following tests:

1. Check Voltage at CD Box, red center wire in plug under CD box with key on - 12.16V - good



2. Check resistance between CD Box and intake manifold to check ground (.4 ohm) - good



3. Telegraph test - I didn't have a way to hook the plug up to the lead wire from the coil so I used a jumper cable. Anyone see an issue with this? I then ground the base of the plug and then unconnect the signal wire from the distributor. I then turn on the key and tap the signal wire to a ground point. - No Spark



4. So either wiring, coil or CD box is bad. I test the resistance on the coil. Between the two connectors the resistance is .6 ohm.



Resistance from lead to cap and one of the connectors on the coil: 4100 ohms.



I think I need to get a test coil to eliminate that. Also my harness is new, what can I do to check the wiring? Any good tests I am missing?

thanks,
Jesse

1976 911S
Old 03-09-2009, 11:27 AM
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