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Thread: 71 911E fuel filter console and pressure regulator questions

  1. 06-02-2023, 07:23 PM #1
    Stoney911
    Stoney911 is offline
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    71 911E fuel filter console and pressure regulator questions

    Hi all, After a long wait the MFI for my '71 911E 2.2ltr has returned from Germany and is re-installed. However the engine ran poorly, cant be tuned and the prime suspect after a lot of head scratching and testing is the small regulator valve on the front (facing the right side of the car) of the fuel filter console.
    Yes all other "demandments" have been ticked.
    Im now waiting for a new one to arrive shortly from Porsche.
    Frankly it looks like a normal hose adapter but something important lurks within.

    I assume it maintains a constant pressure in the fuel system, including the MFI, that allows fuel to flow through the MFI and any fuel not used passes on back to the fuel filter canister where it again returns through this little guy to the fuel tank in front while pressure is kept constant.
    I cant take my console off at the moment so I wonder what the channels /pathways inside of it looks like?
    And why did they use this method?
    Im sure it has a very good reason.
    But why not just return the unused fuel directly back to the fuel tank via this regulator? Why send it through the filter console/canister again?

    Ive seen threads on here showing the fuel system graphic in the manual is incorrect and I can see that it is.
    Fuel should come in the the right hand side(to the front of the car) through the filter, out the bottom to the MFI, from the MFI back into the console on the left (to the rear of the car) and out through the little regulator back to the fuel tank. Would the engine even run if it was the other way around?


    1. So! does anyone know the pressure value that this regulator is supposed to have? (and at what pressure does it hold?)
    2. What's going on inside the fuel filter canister console?
    3. Why did they make it this way? Because Im sure its for a very good reason that I just cant see - one that does not seem to be in any document i have found.
    4. Has anyone replaced this little guy, the engine hums to perfection and found the world is a brighter place?

    I bow to greater knowledge.

    Thanks in advance.
    Last edited by Stoney911; 06-03-2023 at 12:52 PM.
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  2. 06-03-2023, 06:37 PM #2
    Richy
    Richy is offline
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    There is a spring and phenolic plate / valve that regulates the fuel pressure at around 12 lbs PSI . It seems as though fuel expands the phenolic plate over time and it sticks open and the valve does not maintain the correct fuel pressure .
    I've replaced ones that were sticking badly , it made a huge difference .
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