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Vtec problems. (I never kicks in)

Discussion in 'HYBRID -> EG-EK / DC' started by Grifter, Oct 4, 2005.

  1. Grifter

    Grifter Member

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    Put a B18C into a 96 Civic hatch.

    Vtec worked for about a week and since then I have had nothing

    I have been searching this site for about an hour trying to find someone with a similar problem but have not been able to find anything.

    I know the wiring is good to the solenoid and oil pressure sensor. The gauge cluster heat indicator is about 1/3 of the way up after running for hours. The oil is topped up.

    Every once and a while I will throw a CEL for speed sensor. I have replaced the speed sensor and still get the code. Weird thing is I have NEVER had a problem with the speedometer.

    What else is needed to make Vtec work?
    How can I test the Vtec solenoid and the Oil Pressure sensor?
     
  2. VTECin5th

    VTECin5th Administrator

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    Oil level/pressure.
    MPH.
    Engine Temperature.
    Do you have any other CELs on?
     
  3. Grifter

    Grifter Member

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    Oil level/pressure.
    MPH.
    Engine Temperature.
    Do you have any other CELs on?



    nope, just no vtec.
     
  4. eg6sir

    eg6sir Supa Mod Moderator VIP

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    did you wire the knock sensor? or ground it atleast
     
  5. Grifter

    Grifter Member

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    Tested the solenoid.

    It clicks when I apply +12Volts

    What temperature does the engine need to reach for Vtec to engage?


    I will hook up my other ECU with data logging to get the engine temp, I just need to know what normal values are.


    knock sensor is wired.
    The Vtec did work before, I have checked and rechecked all the wires.
     
  6. VTECin5th

    VTECin5th Administrator

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    Weird, and according to my l33t temp gauge i run at about 150-170.
    VTEC is ready at around 100 on my gauge.
     
  7. Grifter

    Grifter Member

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    Uberdata has the temperature at around 180 degrees

    When I am hard on the car it seems to peak at about 195 degrees.

    I rechecked the oil and topped it up again, It didn’t help.

    Uberdata never registers the MPH from the P72 ECU, does anyone out there use Uberdata with a P72? Does the MPH section of data logging work for you?

    My Gauge cluster works great, accurate for speed but it looks as though the ECU thinks I am always going 0MPH.

    That could definitely be my problem, I think Vtec only works when you are moving faster then 30MPH.
     
  8. VTECin5th

    VTECin5th Administrator

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    faster than ~11mph.
    But yea that would definately explain your problem.
     
  9. TeamUrbanChaos

    TeamUrbanChaos Certified H22 Super-tech

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    yea that would be a problem but you said your VTEC used to work with the ECU you have now so it not looking for a speed or thinking its not going anywhere ( 0 mph) is probably not the problem. id check and recheck ur wiring. double and tripple check you wiring connects, anything wires you might have cut and rewired or souldered, check those again cuz ur problem sounds like somethings not hooked up or something just came out of place because you did say it use to work. shit rarely just stops working like that and if it did the ECU would tell you what up (i.e: CEL)
     
  10. Grifter

    Grifter Member

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    Double checked the wiring with a multi-meter (no problems)

    Tried a new ECU (another UNModded P72), Still doesn’t work.

    Is there a way to test the sensor for oil pressure, maybe it’s broken so the ECU thinks there is not enough oil. If that sensor is broken would it trip a CEL?
     
  11. reckedracing

    reckedracing TTIWWOP VIP

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    i would think it would trip the a CEL


    you could always run the car with a 12 volt + with a toggle switch to the vtec solonoid...

    once you get to normal temp and speed try accel'ing and throwing the switch, see if it engages vtec for you

    THIS IS JUST A TEST AND SHOULD NOT BE USED daily...
     
  12. 2naboy

    2naboy Member

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    Have you checked the lost motion assembly if those are not moving freely, vtec will not work properly. Have you cleaned the selenoid. You know simply checking if the selenoid is clicking on and off is not enough, you need to see if power is getting to it when at operating temprature. Use a power tester and see is power runs through the green wire when the engine revs past the vtec engagement rpm. This will tell you if power does indeed get to the selenoid and then from there you can narow your problems further more.
     
  13. Grifter

    Grifter Member

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    I will check the lost motion assembly (after I figure out what it is, google here I come)
    I have tried an entirely different solenoid with the same problem, but I will try cleaning the new one.

    I will try hooking a wire to the solenoid and passing it inthrough the passenger window. Then I can connect a multimeter to the wire and see if its fireing. If its not I will try shorting the wire to +12V while I am in the Vtec range.

    If Vtec then engages that means that the solenoid works great and my problem is with something else. If that does not work then it must be dirt in the solenoid or maybe this "lost motion assembly".
     
  14. VTECin5th

    VTECin5th Administrator

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    We cut the horn wire once and wired it up to the solenoid for this exact test.
    Trace the wire that tells your ECU how fast you're going, if your datalogging showed you going 0, that is most likely the problem.
    I have a chip that has 'full time' VTEC on it, where i could be at 0mph and ready for vtec, i could let you use it if you need.
    I still think it's your 0mph reading.
     
  15. Grifter

    Grifter Member

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    well I just tried burning a new chip
    the new chip has no speed requirement for VTec and it still doesnt work.


    I will try hooking Vtec up to the horn today. :)
     
  16. VTECin5th

    VTECin5th Administrator

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    Your car is brokeded [​IMG]
     
  17. Grifter

    Grifter Member

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    Vtec works like a charm when I attach a wire to the solenoid and cross it with +12v while driving.

    so it looks like the problem is with Vtec requirements

    Does anyone know how to better debug the sensor problems? My data logging indicates that the temperature is in the proper levels. So how to I check the oil pressure sensor? Oil level sensor? VSS sensor?
     
  18. reikoshea

    reikoshea HS Troll...And Mod Moderator VIP

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    well you could go F&F and make a lil "NOS" button for VTEC.

    Im quite sure its your VSS...if you get your car to recognize the fact that youre moving, it might be a little bit more willing to give you vtec.
     
  19. Grifter

    Grifter Member

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    Well I can check the wires one more time.

    I have replaced the VSS sensor (a few weeks ago) with no change.
    The Speedo works great. It knows my speed, it doesn’t bounce around etc.
    I have also tried burning a new chip for the ECU that takes away the speed requirement.


    But hey, apparently I am missing something. I will check again.
     
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