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AndrewCologne AndrewCologne is offline
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Join Date: Aug 2015
Location: Cologne / Germany
Posts: 85
First thanks for all your support! Great community.

Im aware of the "Home mode" of the ECU and the resulting 50/50 duty cicle of the freq valve when the O2 sensor is disconnected. Thats exactly what I did and also raised the mixture to about 2,5% CO. And the Car runs smooth and everything is fine.
Some day the idle was bad and when just cruising the engine felt like a bit stuttering.
I went into the system and found out the the common guilty was the O2-relay below the seat, so I put a new one and everything was fine.

Now since some days "sometimes" the idle again shows these symptoms and also when cruising. And then after a few seconds everything runs fine again. To me it seems that theres an unsteady electrical open circuit issue present at some of these CIS "ECU/freqValve" parts.

I hope its again the relay, if not then I have to check the ECU Unit and ... the freq valve itself. But .... replacing one of these devices is expensive.

So THATS why I got the idea of backdating to the 78-79 Fuel Distributor and the matching WUR. So getting rid of the lambda parts of the engine which kills the risk of getting something kaputt which isn't present anymore ;-)
911 SC 3.0, 1982, black, US model
Old 04-26-2018, 12:12 PM
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