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Registered
Join Date: Sep 2008
Posts: 93
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Ignition Help
Drove the car home last night and turned it off to move my wife's car out of the way went back to turn start it and no dice just cranks over. I think I have narrowed the problem to the ignition system. Here is what I have check so far.
pulled a plug wrapped threads with a jumper wire and grounded the other end on the plate the coil is mounted on and I could not see or hear any spark at plug. This is day light so I'm not sure how visible it would be. CDI hums with ignition on so that seems OK Swapped known good coil form another SC no change. Cap rotor and wires all changed in the last year I'm at a loss as to what to check next. Help! Nick |
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09-21-2013, 06:26 AM
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Registered
Join Date: Jul 2001
Location: Portland Oregon
Posts: 7,007
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Nick,
Can I assume you have a 911 SC??? If so,....remove a plug, re-install the plug connector and lay the plug against anything ground. Then have someone crank the engine for you while you watch for a nice blue-white spark. You cannot miss it if everything is working. No spark? I'd be looking for another CD box if that other coil didn't make any difference.
__________________
Steve Weiner Rennsport Systems Portland Oregon (503) 244-0990 porsche@rennsportsystems.com www.rennsportsystems.com |
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09-21-2013, 07:03 AM
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non-whiner
Join Date: Aug 2012
Location: Slightly right of center
Posts: 5,235
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Put a timing light on the coil wire while you crank it. Does it flash? If yes, put the timing light on a plug wire while you crank it. Does it flash?
If no to the first question, your ignition module or cdi may be bad. Apply normal troubleshooting.
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"Too much is just enough." |
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09-21-2013, 07:04 AM
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Registered
Join Date: Sep 2008
Posts: 93
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Thanks for the replies. Yes my car is an SC and the borrowed coil came off an SC. Different years 79 & 81. Can the CDI be bad if it is humming with the ignition on?
Ignition module? Nick |
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09-21-2013, 07:57 AM
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Straight shooter
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Quote:
__________________
“Of the value traps, the most widespread and pernicious is value rigidity. This is an inability to revalue what one sees because of commitment to previous values. In motorcycle maintenance, you MUST rediscover what you do as you go. Rigid values makes this impossible.” ― Robert M. Pirsig, Zen and the Art of Motorcycle Maintenance: An Inquiry Into Values |
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09-21-2013, 08:02 AM
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Registered
Join Date: Sep 2008
Posts: 93
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No flash from the tieing light on either coil wire or #1 plug wire. Going to swap out CDI with known good one.
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09-21-2013, 08:55 AM
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Registered
Join Date: Sep 2008
Posts: 93
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Swapped CDI and she fired right up. Lesson learned humming / whistling CDI does not equal good CDI. Thanks for the help everyone
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09-21-2013, 11:12 AM
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Registered
Join Date: Jul 2001
Location: Portland Oregon
Posts: 7,007
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Quote:
__________________
Steve Weiner Rennsport Systems Portland Oregon (503) 244-0990 porsche@rennsportsystems.com www.rennsportsystems.com |
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09-21-2013, 11:46 AM
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P911
