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Do I have bad coils?

 
Old 12-04-2018, 06:44 PM
  #1  
Neil Savani
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Default Do I have bad coils?


Iím pretty new to the forum, and to the 964 world. I bought the car a little over a year ago, and so far itís been pretty problem free. I recently had the car sit for 3-4 weeks, and went to drive it today and after a few minutes got an intermittent beeping sound couple with random lights coming and going on the dash. Possibly just a low voltage from sitting, or possibly need coils replaced aka Christmas tree effect. Hereís a link to a short video of the issue: https://imgur.com/a/63nRW9J

and a quick pic just to make an introduction





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Old 12-05-2018, 12:39 AM
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cjoenck
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I would check battery first and then alternator. It looks like an electrical issue.
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Old 12-05-2018, 12:46 AM
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simonstorey
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Originally Posted by cjoenck View Post
I would check battery first and then alternator. It looks like an electrical issue.
2nd that. Could be low voltage, and the easiest place to start.

One of my coils was corroded internally and had a similar effect. Easy tell a bad coil from visual inspection
Under the cap.

If your car is a C4 then also check the accumulator or listen for the pump running for a long time.
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Old 12-05-2018, 06:12 AM
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newsboy
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Your voltage at idle should be around 13-14 volts. You should also check battery, starter grounds. Many have reported that old or dying coils will cause the" Christmas Tree Effect".
Hard to really test coils, they can test positive, and still have internal faults.
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Old 12-05-2018, 08:47 AM
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Goughary
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Where are you located. I have some extra coils - looks like you need to replace yours. If you happen to be near Connecticut let me know.
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Old 12-05-2018, 08:58 AM
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Rocket Rob
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How old are your spark plug wires, caps and rotors? The Christmas tree effect is caused by high voltage leaks at either the spark plug wires, coils or distributor caps.
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Old 12-05-2018, 09:35 AM
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Silvertarga
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If it is the coils do NOT waste money on the Bosch Silver coils, they are garbage. Convert to the 993 coil pack instead, search this forum for info on it
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Old 12-05-2018, 06:15 PM
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Neil Savani
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Just charged the battery overnight, idle voltage is at 13.5 today. Revs dropped every minute or so at idle, and still had the Christmas lights after driving a few minutes. I guess I’ll have to look into a 993 coil conversion, seems reasonably simple to do.
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Old 12-05-2018, 06:20 PM
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Neil Savani
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Originally Posted by Rocket Rob View Post
How old are your spark plug wires, caps and rotors? The Christmas tree effect is caused by high voltage leaks at either the spark plug wires, coils or distributor caps.
They were changed about 11 years ago according to service records from previous owner.
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Old 12-05-2018, 07:06 PM
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When it's pitch black outside - start the car and spray a light mist of water around the plug wires...if you see blue sparks, you know you have leaks in the wires.

If by 11 years, you mean the caps and rotors as well, then those are due regardless. Don't buy beru caps and rotors. Beru wires are fine, but their caps and rotors are garbage. Bosch for caps and rotors only.

The 993 coil swap is simple. So if you are of mind to spend to do that, get that done. They are much more reliable.
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Old 12-18-2018, 05:17 PM
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Neil Savani
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Thanks for all the everyone. I went ahead and converted it to 993 coil pack and the issues went away.
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