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Thread: 911T 1973.5 First CIS K jetronic system

  1. 01-29-2023, 01:26 AM #1
    Ricardo porsche
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    911T 1973.5 First CIS K jetronic system

    Hallo,
    I am searching for owners of this type of porsche.with the first CIS system still installed.
    To get help with the finetuning of the revised motor and CIS system.
    Especially my question is how the valve 0438160 001 influences the measured system pressure and WUR pressure?
    Thanks a lot for your help
    Ricardo
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  2. 01-29-2023, 11:57 AM #2
    Jay Laifman
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    I have a 73.5. I've had it for 35 years. I recently bought a NEW throttle position valve from Porsche. Yes, new, yes from Porsche. It actually did make a nice difference. I have not gone and measured the exact pressure differences. I did take one apart and they work just like the image. There is a cam that richens at lower and higher rpm. The slope on the lower side is longer than the one on the top side. But it definitely starts richening before WOT.

    Also, the mounting of the valve has slots. So you can adjust it a little. I've never found a resource that gives exact details on how to adjust. I tried three spots: at both ends and in the middle. I found that rotating it to bring in full lean soonest seemed to do the best.

    Does that help?
    Last edited by Jay Laifman; 01-29-2023 at 12:10 PM.
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