1st Gen R53 Cooper S Possible throttle body issues???

Discussion in '1st Generation: 2002–06 R50, R53 & 2004–08 R52' started by panaphobic, Aug 12, 2013.

  1. panaphobic

    panaphobic Club Coordinator

    Jul 19, 2010
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    I have an '05 R53 with just over 155k miles on her. Over the past few years while at MOTD and for a few weeks after that, I have noticed something strange with my MINI. Normally, I don't beat on my MINI too much, or at least not like I do at MOTD lol.

    It's kinda hard to explain, but while the throttle is about 27%-30%, you can hear what sounds like a bird quickly chirping (normally on NC-28 going through the hills in 4th gear would recreate the sound). Each year after MOTD, it would eventually go away and stop making the noise. The sound is most likely a small "flutter" in boost.

    After last year's MOTD (2012), it never went away, and progressively got more noticeable. I thought maybe the bypass valve was wearing out and was "fluttering" a bit under low boost. So I bought a new one and installed it. That made no difference at all though. I replaced the vacuum lines and hoses, but nothing fixed it. So I said whatever, much like the weird vibration sounds from the interior panels you get while going through the twisties. I never noticed anything mechanically wrong or felt a power loss or anything, so I figured it wasn't anything worth investigating further.

    After this year's MOTD, the problem got worse. Not only does the "chirping" sound happen at around 30% throttle, but between 50%-70% throttle, it makes a much louder "flutter" that you can actually feel in power fluctuation, along with actually seeing a flux in the boost (on my ScanGauge). No matter what gear I'm in, or how fast I'm going, or what RPM I'm at, time of day, engine temp, or air temp, it's always the same. You can hear the boost dropping out momentarily and coming back and repeats until you give it more or less throttle. It feels like a valve is fluttering slightly. At 100% throttle (which reads as "88" on my ScanGauge - whole different debate there lol), you have no problems at all. I don't have a D-1 spec controller or Sprint Booster either and the TPS on my ScanGauge does not register any flux in the TPS when this is happening. The tach does not show any flux either (both the factory and the one on the ScanGauge).

    I have minor modifications to the motor itself (plugs, wires, coil pack, intake, exhaust, 15% pulley). I have checked for vacuum leaks but I cannot find anything. I have replaced the intercooler bellows, vacuum lines, bypass valve, etc., but can't seem to isolate the problem. I am not getting any engine codes, and the ScanGauge does not show any flux in the TPS, but does show between 1-3psi on the boost during this flux at 50%-70% throttle. Although that is tough to read since the ScanGauge refreshes at once per second, it could be more or less than that. I don't have an actual boost gauge to more accurately record the problem. It is a noticeable power flux though, and you can definitely feel it, even in 4th.

    I had the supercharger oil changed out during MOTD and the old oil didn't have any metal shavings in it at all. That made no difference to it as well. Had all my pulleys checked when my crank pulley failed this year, and nothing was recommended to be replaced along with that. And like everything else, that made no difference at all.

    What I'm thinking is that the throttle body is possibly wearing out. The spring that works the valve, or maybe the valve itself, is loosening up or losing it's spring and is allowing the valve to flutter a little bit. I just find it weird since it doesn't do it under the "chirping" throttle range, between 30% to 50% throttle, or over 70% throttle.

    Has anyone ever encountered this problem and can shed light on it? I really would not want to spend a couple hundred bucks on a new throttle body if it's not the problem. It really has me stumped!
     
  2. MCS02

    MCS02 Moderator
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    Everything I thought it may be you have checked. The only two I can think of is maybe the belt tensioner has gone bad or perhaps the oil leaked out of the SC after it was changed. But I doubt the last on.
    Sorry not much help.
     
  3. panaphobic

    panaphobic Club Coordinator

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    I also replaced the tensioner a couple years ago. I don't think the oil in the supercharger would cause it. It did this before the change and after without any difference or resolve. I can't think of anything else that could cause it other than the throttle body. I'm open to all suggestions before I drop a bunch of money into a new throttle body.....
     
  4. rusnazzy

    rusnazzy New Member

    Jun 11, 2014
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    Was curious if you found the cause

    I recently got an R53 that has had mods done and now I am getting a chirp sound as well however it seems to be when I give it gas. At idle, very faint. Guy I bought it from put new tensioners, new belt, 17% pully reduction and new engine mounts.

    Any help for a paranoid newbee would be much appreciated.

    Scott
     
  5. DJBishopNYC

    DJBishopNYC Member

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    I don't know but buy a mechanics stethoscope, pop the hood & rev it up. You might not know what's going on but you might be able to pin point where the sound is coming from to make it easier to diagnose. However if you want my 2 cents it might be the supercharger or more specifically the metal layer covering the blades. Maybe, maybe not, idk.
     
  6. rchpmini

    rchpmini New Member

    Jun 6, 2015
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    Any update on this? My mini is having similar problems and I cant seem to find any troubleshooting for it. Any help is appreciated.
     

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