Ignition Gremlins
10-20-2002, 11:08 AM
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Ignition Gremlins
HELP! My 76 930 engine that currently resides in a 76 911 has a glitch that is driving me nuts (short trip, and I was heading that way anyhow). It seems that I lose spark to the coil after driving the car for 15-20 mins. New coil wire installed with no change. Could it be the coil itself, or possibly the Permatune box. Maybe now would be the time to upgrade to a MSD.
10-20-2002, 11:32 AM
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Just went through this on a 85. It turned out to be both. I replaced the coil and the Permatune since I was short on time. You can test the coil with an Ohm meter. Mine was bad. Also there are test procedures on Permatune's web site as well. Also you can call Permatune and they will test it for you if you send it to them. Just takes time. Good Luck.
10-20-2002, 12:17 PM
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RO Thanks for your reply. I would like to know the ohm readings on the coil. I had assumed that the coil either worked or it did not. This is maddening, as the car will run like a raped ape, and then just crank and crank, with the eventual smell of fuel (this makes me comfortable as I know that fuel is reaching the engine) Rather than replacing the permatune I will go to the msd unit, as I have heard that these type of problems are endemic to the permatune.
10-20-2002, 10:01 PM
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Here is what I used. Got this from the service manuals.
Coil primary .1 to .165 ohms (Term A and B) - mine showed no resistance
secondary resistance either small terminal to center 390 to 670 ohms ...Mine was less than 100
hope this helps
I replaced both to be sure and am in the process of getting the Permatune unit checked out. Based on what I have seen the bad coil causes the Permatune unit to overheat and shut down as a protection measure. Once it cools off it starts back up. I had a tough time trouble shooting it because it was so intermittent. Try the <a href="http://www.911turbo.com" target="_blank">www.911turbo.com</a> site and search on ignition or permatune for more info. This seems to be a common problem on the mid 80s Turbos. Also some have stated that it could be the little relay near the fuses in the rear engine compartment. You can take it out and remove the cover to confirm the relay is working. Good luck..RO
Coil primary .1 to .165 ohms (Term A and B) - mine showed no resistance
secondary resistance either small terminal to center 390 to 670 ohms ...Mine was less than 100
hope this helps
I replaced both to be sure and am in the process of getting the Permatune unit checked out. Based on what I have seen the bad coil causes the Permatune unit to overheat and shut down as a protection measure. Once it cools off it starts back up. I had a tough time trouble shooting it because it was so intermittent. Try the <a href="http://www.911turbo.com" target="_blank">www.911turbo.com</a> site and search on ignition or permatune for more info. This seems to be a common problem on the mid 80s Turbos. Also some have stated that it could be the little relay near the fuses in the rear engine compartment. You can take it out and remove the cover to confirm the relay is working. Good luck..RO
