Engine Drivetrain 1st Gen Cooper S The mysterious power lag

Discussion in 'Tuning and Performance' started by BlimeyCabrio, Jun 13, 2009.

  1. BlimeyCabrio

    BlimeyCabrio Oscar Goldman of MINIs
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  2. mini_racer

    mini_racer Well-Known Member

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    No, you can't do that, I think you are gonna have to start from scratch over here. :D
     
  3. goaljnky

    goaljnky New Member

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    Blimey,

    I did a quick scan of that other thread, so if I missed something let me know. I had that exact problem few month ago. As a matter of fact it developed on the way to AMVIV. Dealer red the code as 171. Engine bank one running rich, or something along those lines. The car was adulating right at zero boost. Fine bellow, fine above. Then it threw the SES light. Quick summary:

    1. Dealer reset the light. Light on again a day later accompanied by limp mode.
    2. Dealer replaced the BPV. Light on again a day later accompanied by limp mode.

    Three more days at the dealer and they finally ended up replacing the MAP sensor. All was fine until that truck crashed the car two weeks later. So, try your MAP sensor.
     
  4. BlimeyCabrio

    BlimeyCabrio Oscar Goldman of MINIs
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    Dan Z loaned me a spare TMAP - swapped it and still had same symptoms... but haven't tested the pre-SC MAP... do you know for sure if it was the MAP or TMAP they replaced, jnky?
     
  5. k-huevo

    k-huevo Club Coordinator

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    I have not read where you replaced the aftermarket plug wires with NEW (not almost new) OEM plug wires yet (#1 possibility in my opinion), or listed recent code numbers if any. The only failed MAP sensor I’ve encountered North American Motoring - View Single Post - Over Boost Codes. :( more severe symptoms than yours. I’ve had a cracked MAP sensor tube with low signal codes (fixed with rubber hose splice and hose clamps).
     
  6. Tüls

    Tüls New Member

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    what are the codes?
     
  7. BlimeyCabrio

    BlimeyCabrio Oscar Goldman of MINIs
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    NO codes typically. Occasionally a P0172 Rich Condition - happened pretty regularly when I first installed the RMW header - but maybe throws that code once every other month now (if that). Otherwise, no codes. But the symptoms are consistent.

    Jnky - sorry - remembered you have a justa... so only on MAP sensor.

    Keith - nope, haven't replaced wires yet. I'll try my almost-new-OEM ones first... then if that doesn't work I'll buy a new pair...
     
  8. BlimeyCabrio

    BlimeyCabrio Oscar Goldman of MINIs
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    More clues perhaps?

    Remember - the only symptom I see is this:
    [​IMG]

    100% accelerator pedal input results in momentary WOT, then throttle closes to about 50%, then when I pass 4000RPM it opens back up to WOT.

    While the car isn't producing any drivetrain P-codes, it DOES have some persistent CAN errors:
    [​IMG]

    Just starting to dig into these as I only got a scantool that could see them yesterday. But I suspect they've been there a while, as Dan Z said he saw some codes like this when he scanned my car a while back.

    Ideas? Related? Unrelated? Possible causes? Troubleshooting suggestions?
     
  9. goaljnky

    goaljnky New Member

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    Actually this was on my JCW. I can't recall if it was MAP, or TMAP. I can find the paperwork tomorrow and let you know.

    P.S. Your car's symptoms sounds strangely like what mine was doing. Last drive before they replaced the sensor I could only drive either WOT, or coast. Any partial throttle would send the car into limp mode.
     
  10. goaljnky

    goaljnky New Member

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    Just found the paperwork. It was the TMAP.
     
  11. Vernon29RW

    Vernon29RW New Member

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    The one in the front of the engine in the intake manifold is the TMAP?? So where is the MAP? Is it located in the supercharger inlet tube?
     
  12. BlimeyCabrio

    BlimeyCabrio Oscar Goldman of MINIs
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    Yep - TMAP is on the front of the intake manifold.
    MAP is on the SC inlet tube - you can see the plug between the airbox hose and the engine.
     
  13. theCapn

    theCapn New Member

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    If the alternator is in "release mode" at WOT, then the there could be a voltage drop. As seen in the 5E19 section of that screen shot.

    That could cause it, a weak battery, or a bad ground somewhere along the way.

    Low voltage can also "starve" the coil, resulting in a rich condition.
     
  14. BlimeyCabrio

    BlimeyCabrio Oscar Goldman of MINIs
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    Soooo....

    My flex joint on my RMW header broke. No worries - Jan is gonna fix it for me - so I took it off and put my OEM header back on. Guess what? The Power Lag issue is GONE. Car runs better than EVER - certainly better than the last 6 months. The pulley/one ball / intake / injectors / plugs / DT BPV / water-meth / RMW tune config ROCKS. I didn't have the meth kit installed before the header went on - so I haven't run this combination of mods before. I love it.

    I'm thinking now that the car may have been running lean at WOT and midrange RPMs with the tuned maps Jan did for my car with the cam, due to the increased flow with the header. Car wasn't getting enough fuel, so it reduced throttle to compensate maybe? Not sure how or why if it was in open loop at WOT... but something like that seems to have been going on.

    I'm pretty confident the car ran WELL with the cam+header for the first few months after I had it installed - because it rocked at VIR in November, then the lag seemed to develop with the yo-yo in December. So I'm going to have the header fixed but won't put it back on until I can have it re-tuned. And I'm keeping my current tune in case I want to revert back to the OEM header config - I'm also liking the reduction in decibels after several months of LOUDNESS.

    Frankly, dealing with some exhaust issues has made me proficient enough at header swaps that I might even swap headers before and after track events, since I only do that a few times a year... and use Jan's flashloader to swap between the current tune and the header tune... it sure is nice to have a much quieter (and nearly as fast) car as a daily driver... and I can swap headers in about an hour now that I've learned some tricks.
     
  15. BThayer23

    BThayer23 Well-Known Member

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    Sweet! A little bit of automotive serendipity, eh?
     
  16. FERNO

    FERNO New Member

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    Lean under boost? I bet that thing was hitting hard as hell when the throttle wasn't cutting out. I've never dealt with mini compression, but on some of the cars I've driven, that would have caused some interesting issues.

    Speaking of which, when these cars cut out, do they cut fuel like most factory ECU's or do they cut spark like MSD, et cetera?
     
  17. BlimeyCabrio

    BlimeyCabrio Oscar Goldman of MINIs
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    Sooooo.... remember how I said this had resolved itself when I went back to the OEM header? Well, it had for a while. Then it started developing a *little* bit of lag that opened up at about 4000 RPM. Now it's doing it pretty much exactly like it did before I swapped back to the OEM header - and NOTHING has changed. So I'm having the exact same symptoms as before - can't hold open WOT until the car hits 4000 RPM - then the car goes like a batouttahell. There's a ton of power that I'm missing between 2500 and 4000RPM... GRRRRRRRRR...... WTF????

    I'm gonna do some data logging, then put the RMW header back on in the next few days and get Jan to remote tune it and see what happens...
     
  18. BThayer23

    BThayer23 Well-Known Member

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    That sucks, Paul. If it makes you feel any better, my flat tire light finally came back on with the rain at the end of the week. Made it through three rainy days, and then it gave up and came on for the fourth and fifth rainy days. I gotta clean those sensors next weekend.

    Hope you can find a fix.
     
  19. mini_racer

    mini_racer Well-Known Member

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    Get on the phone with RMW and arrange a remote tune if you can't get him to come out there, meaning not enough cars for a tune party. there has got to be a shop close enough to you with a dyno and AFR capabilities.
     
  20. Father Deth

    Father Deth New Member

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    Paul, I'm still with you on this. My car has seemed to fix the misfire codes, but there is still some hesitation involved. In all realness, what it feels like to me is fuel starvation. I'm almost wondering if the fuel pump needs to be changed, or if I need larger injectors.
     

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