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AndrewCologne AndrewCologne is offline
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Join Date: Aug 2015
Location: Cologne / Germany
Posts: 85
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For a prototype with OEM look and OEM connections I took an old CIS ECU Box and removed the old circuit board. The new board came with the needed components and its working flawlessly, means no rewiring etc needed, just plug an play as its OEM like.

The DC regulator is still a stand alone device mounted on the board but will be changed to a solution which is integrated with single elements into the board layout.
The LCD display will be connected later via a disconnectable external plug solution

BTW: With this broadband lambda setup I recognized that when accelerating over 5 sec., the combusition tends to suffer from a too lean mixture!
A fixed factory default 65 % duty cycle should result in at least a 13.5:1 AFR but about 15.5:1 was the reading. So I guess independent from the ECU my CIS maybe suffers from a system or control pressure drop. I'll check that. Would be nice to know if this also happens to other lambda-CIS based engines build in '80-'83. At a first quick view the voltage at the fuel pump is 11v when circuit reaches the pump when key is "ignition on" and about 12v when engine is running, to me this looks ok.
911 SC 3.0, 1982, black, US model

Last edited by AndrewCologne; 10-01-2018 at 04:01 AM..
Old 10-01-2018, 03:57 AM
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