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VTEC without VTEC ECU?

Discussion in 'ECU's, Electronics, and Tuning' started by MokujinX5, Jul 11, 2003.

  1. MokujinX5

    MokujinX5 Senior Member

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    The VAFC is installed, but the VTEC isn't running. I've got a 2000 EX ECU, but it's OBD2b and doesn't match up with my 98 LX harness (OBD2a).

    How can I get the VTEC to work?
    Any point in changing fuel settings when not running VTEC (will it hurt or help)?
     
  2. blundar

    blundar Senior Member

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    check your wiring. The VAFC can activate vtec with a non-vtec ECU. Did you run a wire from the VAFC to your vtec solenoid? That's all you really need to do...
     
  3. MokujinX5

    MokujinX5 Senior Member

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    I had a shop install it for me (I wanted it to look good also). They ran a wire to the VTEC solenoid and stuff, but still no VTEC. I don't have an oil pressure sensor either... do I really need one?
     
  4. pills_PMD

    pills_PMD Super Moderator

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  5. IDMaxGuy

    IDMaxGuy Senior Member

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    Since VTEC engages on oil pressure Im gonna go ahead and have to say.... yesh.
     
  6. blundar

    blundar Senior Member

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    I'm sorry, but I'm going to have to disagree with the majority opinion here.

    VAFCs have no input for a vtec pressure switch.
    VAFCs have a single wire output for vtec that goes directly to the solenoid.
    VAFCs make no use whatsoever of the circuitry in the ECU to activate vtec.

    I know this certainly because most of the cars I / my shop work on are OBD0 cars, which are all non-vtec if they were made in the US. In the past month I've seen a D16Z6 90 hatch, LS/vtec 92 teg and a mini-me powered CRX run very well with a VAFC activating vtec. None of these three cars had VTEC ecus. None of these 3 cars had a vtec pressure switch involved.

    Bottom line: if you are POSITIVE that vtec is not engaging (how do you know for sure???) then the solution is to check the wiring on the VAFC. I'd bet $20 that is what the problem is. Just because a shop did it doesn't mean they did it right.
     
  7. rudeludenotmeanthough

    rudeludenotmeanthough Senior Member

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  8. MokujinX5

    MokujinX5 Senior Member

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    Hmmm... ok. I'm certain that the VTEC isn't activating because the VTi and VTo signals are both off all the time, even when the accelerator is floored driving around town.
    Edit: The shop is reliable (in my eyes) they've done plenty of VTEC controllers before. However, I'm not sure how many, if any, OBD0 or mini-me's they've wired VTEC up on.
     
  9. blundar

    blundar Senior Member

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    I can understand the vtec-input signal being off all the time. You don't have a vtec ECU. You will never have a live vtec signal from the ECU.

    If your VAFC is never setting the vtec out signal high, then that right there may be your problem. What RPM is your VAFC set to activate Vtec at?
     
  10. MokujinX5

    MokujinX5 Senior Member

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    It's set to activate VTEC at 5K rpm. What wires should be going where? That way I can let the shop know and they can check the wiring.
     
  11. MokujinX5

    MokujinX5 Senior Member

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  12. MokujinX5

    MokujinX5 Senior Member

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    **BUMP**

    No one knows??
     
  13. ReallySlowEg

    ReallySlowEg Junior Member

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    Could you activate vtec with something other than a VAFC? What does it need to turn on ? The bare essentials that is.
     
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