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Bob Kontak Bob Kontak is offline
The Mighty Pieholio
 
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Join Date: Nov 2007
Location: North Canton, Ohio
Posts: 14,320
Garage
I own an 81 911 with CIS. In 15 years of ownership I have only encountered your type of problem when I had Permatune boxes on the car rather than the Bosche CD box. I bought the car with a Permatune box so never had a CD box. I am not certain if the Bosche CD Box will just fail for the hell of it like the Permatune box did.

I talked to Paul Weir six years ago and he said "Buy yourself some insurance with the MSD 6AL box." I put one on, mounted it under the driver's seat and have never had the same problem again. I see NASCAR race cars having twin MSD boxes on their dash boards so an extra two or three feet of wire ain't gonna slow you down. That's a separate discussion though.

I would replace the relays others have mentioned. I would disconnect the battery and test all the fuses in the front trunk for continuity using a multi-meter. Check the big wire harness connector in the rear of your engine compartment on the driver's side. With age a male pin can be pushed back out of the harness and drop a connection. The distributor "green wire" and related connections are critical. Permatune's site has a lot of good info on troubleshooting these connections. You will need a multi-meter and some patience. It is not rocket science so a person with average DIY intelligence can follow the logic given time for a learning curve and the proper instructions.

For less than $400 and AT LEAST one weekend of tedious, anal retentive wiring and installation the MSD box will fix your problem if all else fails (Do not be fooled by the 4 hour or so installation claims) I like the under the drivers seat mounting as you can then secure the main box ground to the transmission ground - but I am biased as this is how I did it. There is not a lot of space to throw around in the 930 engine bay so this may relieve some congestion. You can then mount your coil to where the old CD box was. You may have to get a tachometer "thingie" that helps with something or other to make your tach work correctly, All are available from our gracious hosts. Search on "MSD 6AL"

Best of luck. I will betcha it is the CD box or something real real simple.
Old 05-22-2010, 03:52 PM
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