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AndrewCologne AndrewCologne is offline
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Join Date: Aug 2015
Location: Cologne / Germany
Posts: 85
There have been a dozen threads where people asked how to remove the freq valve but .. as the Lambda based 930/16 engine comes with a diff. fuel distributor you can't just compensate the resulting leaning out of the system when the freq valve has been removed as the pressure of the FD's low chambers would simply be screwed up.

As the original ECU is very simple and based on a narrowband O2 Sensor it comes with some slightly noticeable disadvantages like i.E. a slight hunting idle.
This is due to the very inaccurate narrowband 0-1v voltage jumps provided to the ECU.
But thats just one issue.

Also in Germany this inaccurate and prehistoric type of 3-way lambda control won't let pass the 930/16 based cars to obtain a "green sticker" permission to drive within cities where only cars with green stickers are allowed to drive.
With a very accurate lambda and therefore AFR control incl. a more modern type of catalysator it could be that the emissions will be within the "green sticker" specs.
911 SC 3.0, 1982, black, US model
Old 07-03-2018, 08:22 AM
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