10-20-2018, 06:12 AM | #1 |
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Problems with manual transmission gear shifts
Hi!
There is something weird going on, that started a week ago, without me doing any changes to the car (135i N55 late 2012)whatsoever. When shifting from 2nd to 3rd (other gears as well) for example at say 2000-3000rpm, when stepping on the clutch, the car thrusts forward a little bit, as if there was a really small amount of gas applied. This results in a jerky shift. Normally while pressing the clutch I get off the gas almost simultaneously, having a small amount of gas still applied when the clutch is fully pressed, due to the delayed reduction of rpm. That results in quick and smooth shifts. Not anymore! It is not happening, when the the shifts are made at lower rpms (1500). It also does not appear, when I release the gas pedal first (completely) and press the clutch afterwards for shifting. The shifting process is still fairly quick for regular driving, but takes twice as long like that. The other thing I noticed, is that I can reproduce that behaviour without even pressing the clutch at all. When applying like 50% throttle, starting from 0, and then releasing the gas padel really quick, the same thing happens. Normally it would "bog" a bit, because of the load change, but now it acts like if there was a reeeelly short burst of throttle applied. You can hear it through the exhaust also. I am pretty much clueless at this point... if it would only happen during shifts -> clutch but the way it is, it could also be the flywheel I guess, which is only 2 years old. I am running MHD with a custom map and already loaded an older version of it and deactivated burble and stuff, but no use. Thought it might get some throttle during shifts through the software or something like that. Any ideas? I made some logs too, just in case it might be a software issue after all. Thanks alot! Last edited by TylerD; 10-20-2018 at 07:49 AM.. |
10-20-2018, 07:53 AM | #4 |
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Do you mean the gearbox?
Sorry, its a late 2012 N55. I added that to the initial post. If it was the valvetronic or injectors, could that be because of the increased wear due to the tuning (custom map still in development and only been like 1000km with tune)? Any other symptoms that could narrow it down to those? Like said, I did some logs, if that would help. Also no codes visible up till now. |
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10-24-2018, 05:18 AM | #5 |
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So I checked the logs from four weeks ago, where it did not happen and there seems to be a slight difference in load request and actual load (see attached images).
Could that be a software problem? I reflashed the previous map and it still persisted when driving right after. Reset adaptions and I think it is getting better now, need to drive around more to make sure. What else might cause this? Its weird, that it is not happening below 2000rpm and above 3500rpm (or not noticable anymore maybe). |
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11-26-2018, 04:35 PM | #6 |
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Ok, so it was completely gone after flashing the previous map, options unchecked (burble, linear throttle) and 3 or 4 starts with regular crusing afterwards.
It has to do something with the specific custom map iteration (which i doubt) or burble/linear throttle. Maybe even the MHD app version, I dont know... Need to investigate further. (just in case someone has the same issue) |
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11-26-2018, 05:01 PM | #7 |
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How old is your engine oil? Is it of the correct viscosity and LL1 rating ?
Like MightyMouseTech said... it could be related to your valvetronic or vanos. The N55 does not have a traditional throttle body... it uses cam timing and valvetronic to control the engine idle. Using the wrong oil... too thick for outside temps, and the ECU could have problems controlling the idle speed. Sounds like it was something in that engine mapping, bc you don't have this issue with your old flash SW. PS: Have you considered deleting your CDV(clutch delay valve)... it's totally worth it in 1st and 2nd gears. Just look for the "CDV delete DIY" thread.
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clutch, flywheel, jerks, shifting, throttly, thrusts |
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