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Diverter valve troubles?

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  • Diverter valve troubles?

    Hi everybody,

    My Fiat GP Tjet has been holding back on power for a day or two. Being the inquisitive arse I am I decided to take apart the entire inlet to find the problem. I came to the divertervalve and I was able to push it halfway open without any effort (about the same pressure it takes to push a full coffee cup across a table). I'm not an expert by any means so I would appreciate any input you guys may have for me. It is an oem part that operates magnetically as far as I can tell.

    Is this normal for a diverter to be able to open halfway without much effort?

    Thanks in advance for the input!

  • #2
    So long as it's vacuum assisted, then yes.
    Because pressure on the inlet side, will be equal to pressure on the back of the valve, resulting in 0 force being applied to open it.

    That said, there IS always a spring (or a magnet in your case? We don't really do FIAT's in Australia) to add 'some' pressure to the off side; so it's possible it's worn; but no, it's not meant to be stiff.

    If it's 110% electronic, and you think it's an electro magnet, apply the correct voltage to it and see if it hardens up.

    As an example, the diverter valve in a WRX opens at like 3-5psi if you leave the tube unplugged (that's the spring weight), however with it connected, those stock top-mount valves can handle well over 20psi.


    • #3
      I've found a service manual in the meantime for the Tjet engine. It is an electro magnet. See picture.
      Could i disconnect the blowoff hose upstream of the valve and check with the engine running?

      Detail ive left out in original post:
      For shits and giggles in the past I have disconnected the valve to make chuchu noises. That worked a charm. That would tell me that it should be fully closed when no voltage is applied; not very scientific I agree... but it would make me assume so.


      • #4
        Well that confirms it takes a direct 12v at least; simple enough to check now


        • #5
          It was leaky! Replaced it. Burning rubber again!