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Put on the head, now we got a weird problem

Discussion in 'Engine Building' started by B16RacerN2NR, Jan 21, 2006.

  1. B16RacerN2NR

    B16RacerN2NR Working Hard VIP

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    Hope this is the right section...

    Well, I swapped a B16 into this kids CRX. It's been running good since the day I put it in back in August. He wanted me to pull the head 2 weeks ago so he can send it to go get ported and to get a valve job. Anyway, we get the head back, I put it back on (new head gasket, new intake and exhaust manifold gaskets, new head bolts) and the Vtec won't turn on and rev limit is at 7500k [​IMG] I went over everything, including the wiring, 5 times and it still acts the same. The car runs fine, doesn't misfire or anything, it's just no Vtec and early redline like I said earlier.

    I try my ECU (it's chipped with a REAL Mugen program) in his car and Vtec turns on and the rev limit is fine, doesn't cut out early. So I take off the Vtec Solenoid and Pressure Switch, clean it up, and it still acts the same way when we use the a Virgin PR3 or PW0 but still runs fine with my chipped PR3.

    Any ideas? No Codes , no nothing. [​IMG]

    Since it works with my ECU I looked at all the things(and wiring) my ECU bypass'... like the o2 sensor, the knock, and Vtec pressure switch.

    If all else fails he said he would send his ECU out and get chipped but I know that just band aids the problem, not fix it. I threw his ECU into my car and it runs fine so it's not any of the ECU's we got.
     
  2. MikeBergy

    MikeBergy Blah blah blah....

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    Well, did you check the voltage on the vtec solenoid when you used his ecu on the car? I can't remember the rev limit on the stock ecu, but check the voltage using a voltmeter to see if the vtec solenoid is getting any voltage, you might just not be feeling it. Just start with the cheapest things you can check. it just sounds like a weird connection problem. VTEC is supposed to be smooth. Is it possible that your friend's ecu has a better tune than your 'Mugen' chip? Also, unless your buddy has some cams, 7500 seems a bit high to be running it anyway. I thought 7500 was a soft cut, unless you have a chipped ecu. But again, I am not sure. I'm obd0 running a programmable pm6, so I haven't run into any of those problems. But check the voltage to the solenoid first, that's easy.
     
  3. B16RacerN2NR

    B16RacerN2NR Working Hard VIP

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    no, stock redline is 8200 and B16's make peak power at 7600, the B16 cams die off some where around 8k. He's got GSR cams, not a big difference but a slight one. Yes VTEC is supossed to engage smoothly but I defintely know it's now hitting at all. I don't understand how it would not be getting voltage with a stock ecu but gets it with my chipped one. I understand that the chp will let Vtec engage even if the Pressure switch isn't plugged in but the solenoid has to be plugged in and it needs voltage to pop. I'll try to test the solenoid. How do I do it exactly? :ph34r: :)
     
  4. driver1

    driver1 Senior Member

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    if the chipped ecu will let vtec engage without the pressure switch hooked up then it will obviously let it engage without the correct amount of oil pressure...that would be what i would check being that there was just head work done...check and be sure there are no oil ports clogged and not letting enough oil pressure up to the head/pressure switch
     
  5. B16RacerN2NR

    B16RacerN2NR Working Hard VIP

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    yeah, this is the conclusion I came to also so i'm gonna pull the head again.
     
  6. Exodus

    Exodus Junior Member

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    I don't want this to sound offensive whatsoever, just giving you something to make sure of, when you pull the head, look and see if the headgasket was put on right side up. Last time I saw issues like this on the dyno, the guy, who is pretty intelligent, managed to put the headgasket on upside down and VTEC was then having problems. Sounds like an idiot's problem but anyone can do it on accident.

    Other than that, I'd recommend checking the head over, you're clearly smart enough to be able to find any issues there. I'd suggest looking at anything at all related to lubrication and flow of oil, that's all I can really think of.

    Oh, was the head milled at all while it was away?
     
  7. B16RacerN2NR

    B16RacerN2NR Working Hard VIP

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    thanks for the thought but i'm positive it was on correctly because I used an OEM head gasket and it says "up" on the side that is supposed to be facing up.

    I was going to pull the head off last night but he said on the way to my house the car was running perfectly fine, VTEC was kicking in at 4900 like it was supposed to and he says it rips. spins gears all the way through 4th...but that's only because he's on bald tires lol
     
  8. get_nick

    get_nick These snozzberries taste like snozzberries... VIP

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    ok, so was this a miracle fix???

    I thought my vtec was out one time and i just wasn't going WOT....
     
  9. SlushboxTeggy

    SlushboxTeggy It's only stupid if it doesn't work VIP

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    i love when stuff fixes itself
     
  10. MikeBergy

    MikeBergy Blah blah blah....

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    LOL I wish my car would tune itself, and the turboedit bugs would just find their way out of the code too... :)
     
  11. B16RacerN2NR

    B16RacerN2NR Working Hard VIP

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    that's why Wil burned me a chip using BRE :mrgreen: plus BRE has rev launch like I wanted and turbo edit does not.
     
  12. MikeBergy

    MikeBergy Blah blah blah....

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    The TurboEdit portion of the program works, but the datalogging portion does not. Plus, TurboEdit does have a launch control feature, and WOT shifting is being developed since TE is now opensource. It's not to the point crome pro is, yet, we'll see as time progresses. I will get into the developing game as soon as I'm done with school this quarter. I have to get into the visual studio more.
     
  13. 97CTR

    97CTR Senior Member

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    It probably was an oil pressure problem, if it worked with your ecu. He probably checked his oil and saw he was low, put some in and holy shit I have VTEC!!!!! If not, then thumbs up for stuff fixing itself.
     
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