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Odd 6mt observations - advice
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02-23-2015, 06:44 PM | #1 |
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Odd 6mt observations - advice
Is the following behavior normal on a 6mt? Hope some experts could shed some light, or warn me of impending doom...
When rolling at 10+ mph with the stick in neutral, foot off the clutch pedal, if I push the accelerator (eg to rev match) the responsiveness is very laggy and slow. It takes more accel pedal and holding it for longer to get the rpm's to rise If im rolling at 10+ mph, stick in neutral, but clutch fully depressed, pressing the accel pedal results in nicer snappier revs, more responsiveness. When fully stopped, or rolling <3mph, revs are also nice and snappy in neutral. I don't remember past vehicles responding sluggishly when revving while rolling... '07 6mt 111k miles original clutch and fly Thanks
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02-24-2015, 09:54 AM | #2 |
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I've never noticed anything like this on my car. I'll try the specific combinations you described today and see if I notice anything.
I don't think this is a transmission issue. It's got to be DME related somehow.
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02-24-2015, 11:14 AM | #4 |
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That's strange indeed. My 6MT exhibits no such issues :/ How is it when flooring it in gear, clutch pedal untouched?
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02-24-2015, 11:29 AM | #5 | |
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02-24-2015, 11:54 AM | #6 |
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Yep, noticed the same thing. The 6MT ECU has a few different things. Holding the throttle open between shifts when aggressively driving to not bleed as much boost off is another one of them.
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02-24-2015, 01:14 PM | #7 |
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Do you think it has to do with the engine spinning just the DMF (neutral w/ clutch depressed) vs the DMF,Clutch, Input Shaft in transmission (neutral w/ foot off clutch).
That may explain why it is revving slower due to more rotating mass "When fully stopped, or rolling <3mph, revs are also nice and snappy in neutral." - is your clutch depressed at this point?
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02-24-2015, 02:16 PM | #9 | |
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02-24-2015, 02:24 PM | #10 | |
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02-24-2015, 02:28 PM | #12 | |
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02-24-2015, 04:53 PM | #14 |
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Same here ! 2009 335xi 115k km (around 71500mi) on original clutch and flywheel.
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02-24-2015, 06:47 PM | #15 |
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when you let go of the clutch pedal (foot off), stick in neutral, the engine is still connected to the tranny. But the tranny is in neutral internally. But that doesn't mean the engine isn't under some load. The engine is still spinning a neutral gear inside the tranny which puts a load on the motor.
Now when you depress the clutch (foot pushed down, no matter what position the stick is in, now the engine is fully disengaged from the tranny. So the engine technically has no load applied to it from the tranny, other than the mass of the flywheel. hence, that's why it will be easy for the engine to rev up faster. |
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02-24-2015, 11:19 PM | #16 | |
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I did a QUICK test today and really didn't notice a difference clutch in/clutch out. I'll try again tomorrow.
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02-25-2015, 12:16 AM | #17 |
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I don't know about the timing, but I have logs showing the ECU just holding the throttle position wide open/slowly drifting closed with foot off of pedal. Cool feature.
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02-25-2015, 08:43 AM | #18 | ||
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