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Fuel rail pressure- suction control valve

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  • Fuel rail pressure- suction control valve

    This is off a rodeo common rail. All the same really.
    Blue is raw signal from fuel rail pressure sensor, they are 5v reference like most sensors. It’s sitting at 1.5v idle will rise to 4v full throttle.
    what controls fuel rail pressure is the suction control valve (SCV) you can see the Green line duty cycle at 37% this will drop to 29% as rpm increases. This SCV is by default open hence smaller duty cycle means open more and more fuel to high pressure pump and higher fuel pressure. If by default closed duty cycle increases to raise fuel pressure.
    Red line is current flow to SCV it sits just under 1 amp, current flow will increase as SCV gums up and hard to open / close. Current flow is a good indicator of SCV health.

  • #2
    Hi mate. here is a suction control valve on the earlier 1kd models. The 1GD has a totally different fuel controller. It is posted on the engine detail thread with a complete diagramatic description of it's operation if it is of any use to you.
    Cheers.

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    • Spook1205
      Spook1205 commented
      Editing a comment
      Hi Davidd, I can’t see a link or find info in engine thread.
      Would be great to have a look at what you are saying. I have only ever seen two types of suction control valves. One is by default open the other is closed. All have worked off a duty cycle.
      Looking at the data and diagrams would mean a lot to me. Especially to see how things have evolved.
      If you could point me more in the right direction of this info that would be awesome
      Cheers mate, Spook

  • #3
    Engines...page p2 ......1GD technical details. Cheers. .

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    • Spook1205
      Spook1205 commented
      Editing a comment
      Ah cool, thanks David.
      I have seen that elsewhere a while ago, yeah it’s different pump, rail and such.
      Operating principles of suction control valve or control valve should be the same, everyone I’ve seen all work on duty cycle with very similar current flow.
      The 2.8 is a pain to get at but I’ll get to it just to be sure. Plus if I check what it’s doing now it will be a good reference in another 150,000 kms or so being a part that deteriorates.

    • Spook1205
      Spook1205 commented
      Editing a comment
      Finally got a chance to sit and read that, some cool shit and maybe a great solution to the issues suction control valves have.
      So rather than controlling what’s going into the pump it’s just bleeding off. So without all fuel being delivered to engine having to go through the component that controls fuel pressure you would think it would have a longer life.
      Thanks David for pointing that out, so much info in this forum when knowledge is pooled and discussed.

  • #4
    I'm not seeing any attachments?
    2016 GX , in White

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    • #5
      http://toyota-club.net/files/faq/15-...engine_eng.htm

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