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Fuel pressure regulator plumbing

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  • Fuel pressure regulator plumbing

    My M3 has the underside of the fuel pressure regulator plumbed into the nearest little air release port ( at a loss for the correct name ! ) . Most pictures I see online of S14 engine bays- all four of these ports have the little rubber stoppers on them. Is this correct, or is either way going to be okay ?

    Thankyou !

  • #2
    The FPR needs a vacuum source, but in stock mode it is not connected like in your picture. The fitting on the throttle body should be capped, and the FPR should get vacuum from the idle control valve circuit.

    The reason is, on an engine with individual throttles, like the S14, tapping into just one throttle, like in your picture, will give very inconsistent vacuum.


    • #3
      I agree 100% with Ironhead. That vacuum line should plug into an in-line fitting between the idle control valve and the throttle bodies.
      Ron ///Man

      • '91 Gr-A Former CiBiEmme / Ravaglia - Sold
      • '90 M3 Faux EVOII Alpineweiss 36K Orig Owner - The Queen
      • '91 M3 Faux EVO III Brilliantrot Euro Driveline - The Rocket
      • '91 M3 Faux Gr-A Club Racer DM - The Alter EGO
      • '89 M3 M3T / ITR Club Racer
      • '94 Spec E36 - Eh....
      • '09 M3 - Tarmac Terrorist
      • '04 330Xi Sport 6 Speed - Snowmobile
      • '07 530 Xi - Highway Star


      • #4
        Thanks for both of you help with this !