The experiance that I have had with many BMW M3 SMG has not always been the best, most of the problems I have had related to the SMG.
Below are some of the problems I have experienced and the potential remedies that have worked for me!
Accumulator pressure loss
I have had to replace many accumulators due to loss of hydraulic pressure. Apparently, the accumulators
do loose pressure over time, especially if the car is driven in a fairly 'spirted' fashion.. flat changing, club days, etc..
The most telling symptom is the long 'buzz up' when the the drivers door is opened upon entering the car.
Typically, after the car has not been driven for a while (say overnight) the hydraulic fliud flows back into the reservior, upon opening the driver's door in the morning there is a 'buzzing' sound as the accumulator pumps the fliud back into the clutch mechanism.
This should gerenally take up to 10 seconds to complete. If this takes longer there is fair chance that the pressure is not holding in the accumluator unit. Another tell-tail symptom is that startup buzzing when the door is opened even straight after driving the car.
As the SMG unit requires this hydraulic fliud to operation the clutch, if left uncheck it can result in non-selection of gears, particlularly 2nd and reverse.
The only fix for this is to replace the accumulator unit which can be quite costly.
Intermittent SMG light on.
Cheap and fast fix would be to check the SMG relay and its base for burn marks caused by the pump drawing a large amount of current on start up.There was a recall on some of the early SMG2 cars and that was to replace the SMG relay and its base (socket).
SMG Reprogramming
I have reprogrammed many SMG1/2 control units. This is a factory/dealer option which is released with other software updates relating to numerous components and models.
What the latest program gives you is a slightly quicker change 1st to 2nd but not by much as these still have to work within BMW specs!
As enhancements are made to the SMG programs are made by BMW and sent to each dealer as part of a general software upgrade, who may or may not install this. In my experiance I had to only do an upgrade when asked by the cars owner and not as a standard scope service.
With the advent of the SMG2 the orginal SMG1 updates are becoming less frequent. I would suggest that when you next take your car in for a scheduled service, you request that they update the SMG software to the latest version they have... (warranty cars upgrade is free)This will not give you "super fast" gear changes but the smoothness and speed improvement you do get will make a difference.
Gearshift slipping out of position
This could be caused by a locking ball and spring which is fitted to the rear of the gearbox to lock each each gear shift in possition.If the spring collapses
there will no tension on the ball to lock the gear into place!
HOPE THIS INFO HELPS!!!!!!!
Below are some of the problems I have experienced and the potential remedies that have worked for me!
Accumulator pressure loss
I have had to replace many accumulators due to loss of hydraulic pressure. Apparently, the accumulators
do loose pressure over time, especially if the car is driven in a fairly 'spirted' fashion.. flat changing, club days, etc..
The most telling symptom is the long 'buzz up' when the the drivers door is opened upon entering the car.
Typically, after the car has not been driven for a while (say overnight) the hydraulic fliud flows back into the reservior, upon opening the driver's door in the morning there is a 'buzzing' sound as the accumulator pumps the fliud back into the clutch mechanism.
This should gerenally take up to 10 seconds to complete. If this takes longer there is fair chance that the pressure is not holding in the accumluator unit. Another tell-tail symptom is that startup buzzing when the door is opened even straight after driving the car.
As the SMG unit requires this hydraulic fliud to operation the clutch, if left uncheck it can result in non-selection of gears, particlularly 2nd and reverse.
The only fix for this is to replace the accumulator unit which can be quite costly.
Intermittent SMG light on.
Cheap and fast fix would be to check the SMG relay and its base for burn marks caused by the pump drawing a large amount of current on start up.There was a recall on some of the early SMG2 cars and that was to replace the SMG relay and its base (socket).
SMG Reprogramming
I have reprogrammed many SMG1/2 control units. This is a factory/dealer option which is released with other software updates relating to numerous components and models.
What the latest program gives you is a slightly quicker change 1st to 2nd but not by much as these still have to work within BMW specs!
As enhancements are made to the SMG programs are made by BMW and sent to each dealer as part of a general software upgrade, who may or may not install this. In my experiance I had to only do an upgrade when asked by the cars owner and not as a standard scope service.
With the advent of the SMG2 the orginal SMG1 updates are becoming less frequent. I would suggest that when you next take your car in for a scheduled service, you request that they update the SMG software to the latest version they have... (warranty cars upgrade is free)This will not give you "super fast" gear changes but the smoothness and speed improvement you do get will make a difference.
Gearshift slipping out of position
This could be caused by a locking ball and spring which is fitted to the rear of the gearbox to lock each each gear shift in possition.If the spring collapses
there will no tension on the ball to lock the gear into place!
HOPE THIS INFO HELPS!!!!!!!
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