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Manual Vtec

Discussion in 'ECU's, Electronics, and Tuning' started by webink_EK9, Jul 8, 2004.

  1. webink_EK9

    webink_EK9 Senior Member

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    Ok, I rewired my horn buttons to the Vtec switch. When I push the horn buttons now, the vtec will kick in. I only tried this once then I cut the wire. When I was going and pushed the button, the CEL came on. Anyone know why? When I turned the car off then back on again, the light was off. Any ideas?
     
  2. YouKnowWhoIBee

    YouKnowWhoIBee my avatar is better.

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    i know you are into autox and stuff but why would you wire your vtec to your horn. I dont get it maybe i am missing something here. :shrug: Please let me in on your thoughts.
     
  3. webink_EK9

    webink_EK9 Senior Member

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    Bored? Something to do I guess. I just read another thread saying it ran off of 12v and I thought...well what if. My vtec is set kinda high right now and I wanted to see what would happen if I made it go when I wanted. It stalls the motor when its just sitting there and I push it. Like I said, something to do.
     
  4. Import R

    Import R Senior Member

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    Does vtec just engage on a 12v source, or does it require a constant 12v source to stay in vtec?

    i only ask because it would seem that vtec would only be on as long as you held down the button for the horn.
     
  5. webink_EK9

    webink_EK9 Senior Member

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    Its still wired to the ECU. I put a diode on the wires so I don't short out the ECU and I also had to put in a relay to switch the horn sig. from neg to pos. It takes a constent 12v signal to keep the vtec on. I just don't know what tripped the CEL.
     
  6. brian11to1

    brian11to1 Senior Member

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    for it engage VTEC there has to be a certain PSI of oil, the enigne has to be at "normal" op. temp. I believe the vehicle has to be at a certain speed... not to sure...
     
  7. YouKnowWhoIBee

    YouKnowWhoIBee my avatar is better.

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    I think it is a cool idea actually. It is interesting how you did it. And my thoughts were if you engage vtec you have to let of the horn to shift so your ecu reads that vtec shut off for some reason before it should have so it is throwing you a code to check out why. Maybe it is throwing you a vtec pressure switch code saying it is malfunctioning and you should take a look at it. And if you were to keep that idea maybe you should wire it to your like a rear defroster switch. That is something accesable(sp) and you turn it on then choose to turn it off. Just my .02... But tell us how it turns out.
     
  8. webink_EK9

    webink_EK9 Senior Member

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    Thats what crossed my mind. A speed setting or something. It does kick in when its just sitting there, but it stalls the motor. Anyway, I may hook it up again tomorrow and play some more. Whats the worst that could happen? Hmm...well just don't tell me :p
     
  9. jamesA

    jamesA Well known pissed off telephone guy VIP

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    cause it's putting too much air into the motor at idle.

    I can see the logic behind something to do, but messing with the VTEC engagement settings is pointless. Honda Engineers built the motor with vtec engaging at a certain rpm for a reason. getting to engage later or sooner is just pointless.

    I have a question, will it kick in at the stock rpm setting regardless of you hitting the button or not? If not your motor will fall flat on it's face at 6000 rpm (I've done it before... thought the motor was warmed up and wasn't paying attention...) 6000 rpm it felt like I hit a brick wall.


    If you want to be able to change the rpm settings, why not just buy a VTEC controller.
     
  10. webink_EK9

    webink_EK9 Senior Member

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    Can't be an always on switch...then when I slow down, the motor would die. Has to be close to my fingers too...kinda like a spray button or something. I'll probably give up on this tomorrow, but we'll see. I'll let everyone know if I blow something up.
     
  11. webink_EK9

    webink_EK9 Senior Member

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    Yeah...it still kicked in on its own. A vtec controler is next on the list, but like you said, its set that way for a reason. It kicks in around 5700 or so...my EX tac is off people say. Anyway, it was for fun. Now I can hook my horn switch up to anything...hmm...Maybe a blue flame thrower??? j/k
     
  12. liquid00meth

    liquid00meth Senior Member

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    thats not really true man. The optimum vtec crossover point is determined by dynoing the car with the vtec lobes only, then with the regular lobes only. You look at where those torque curves cross, and that is where your vtec should be set. Alot of times with modified cars especially, it's not at it's optimum point.
     
  13. jamesA

    jamesA Well known pissed off telephone guy VIP

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    well, modified yeah. torque curves change with different modifications and many variables.

    But just messing with vtec engagement points on a mostly stock motor isn't going to gain you anything worthwhile.
     
  14. radnulb

    radnulb Senior Member

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    the ECU has circuitry to check for funky things with the vtec solenoid.
    unplugging it usually will trigger it via the no-load sense of the vtec transistor.
    running +12v when it does not expect it would probably trigger something too.
    I bet the code is a code 21.
     
  15. liquid00meth

    liquid00meth Senior Member

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    your probably right
     
  16. Import R

    Import R Senior Member

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    I don't think speed has anything to do with vtec engagement. I can sit in my driveway and slowly rev my car up and I can hear it turn on because my exhaust tone growls at me around 5800 when it should kick on.

    I had a CEL come on at the track when I iced my engine for a while. The car was just starting to come up to temp when I made the run. By the time I hit 2nd the car threw the code. I didn't have a piece of wire to bridge the connector to pull the code, but I assumed it was something with the vtec since I wasnt up to normal operating temp.
     
  17. Loco Honkey

    Loco Honkey Banned

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    So what are you doing for extra fuel and spark advance with your finger on the horn? Hmmm?
     
  18. webink_EK9

    webink_EK9 Senior Member

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    I use ether on the carbs and a lighter flint.
     
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