What is the impact of disconnecting the frequency valve connector? | FerrariChat

What is the impact of disconnecting the frequency valve connector?

Discussion in 'Mondial' started by Albert Penello, Jul 6, 2020.

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  1. Albert Penello

    Albert Penello Karting

    Jul 21, 2019
    165
    Woodinviille, WA
    Full Name:
    Albert J Penello, Jr.
    #1 Albert Penello, Jul 6, 2020
    Mostly a thought exercise, but I'm curious. I have a 1985 Mondial QV.

    Pre '85 QV's didn't have the frequency valve setup and ran fine. I have messed around with Mercedes of this era which also have frequency valves added for US markets but usually I remove the whole system.

    What happens if you just removed the electrical connector to the frequency valve? I assume you don't get the fuel metering and fuel just passes through uninterrupted. But I'm curious if doing this make the car richer or leaner and if some other part of the system needs adjustment to compensate.

    From a future-proofing standpoint I don't run Cats in this car, so I really have no need for the rudimentary emissions stuff but I don't want to make the car run worse...
     
  2. spicedriver

    spicedriver F1 Rookie

    Feb 1, 2011
    3,859
    #2 spicedriver, Jul 7, 2020
    The FV provides for enrichment - full throttle, etc. So the car would probably run worse. Assuming the O2 sensor, and injection ECU are working correctly. Cats require a leaner mixture to keep from burning up. With the cats removed, you can run a richer mixture. Open the loop by removing the FV connector, and swap to a vacuum WUR. Make sure to route the WUR vacuum line to engine vacuum (engine side of throttle plate), and not to atmosphere. I use a WUR from a '77 911. Big performance boost, and an easy swap back to emissions setup if needed.
     

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