So, I bought the car just over 4 months back and it has spent more time at the workshop and my garage than on the road. The car was a joy with no issues during the test drive.
Problem 1: Whilst driving on the freeway, I noticed my gear number on the instrument cluster continuously flash but shift ok. At the lights, the car just rolled back as I attempted to accelerate. This was my second day with the car and I started stressing. Thanks to power of google, android smartphone and the BMW community, I learnt that I only needed to shut my bonnet. Did this, and the beast roared again...phew!
Problem 2: I felt the shifts were rough so I got the stealership to do a full codescan and checkup on the car with special attention to the clutch. They gave me the all clear and explained that I needed to get used to SMG as it was inherently rough.
Problem 3: One beautiful hot summer day, while slowing down at the red lights, the car would not gear down from 2 to 1. I would hear continuous attempts at engaging gear but this failed. I turned the car off and on and it seemed to rectify the problem. However, at the next traffic light, whilst gearing down from 6, I heard a loud grinding sound at gear 4 and the transmission cog symbol came on but gears went down to 1 OK. I then drove off perfectly well until home and the cog symbol disappeared by itself. However, when I tried to engage reverse gear after more than 4 hours of the car being off, there was a loud bang-almost as though I was engaging gear without depressing the clutch. The car seemed to drive OK for short periods after this. But after longer periods, I would hear the occasional grinding and banging of the gears.
I took the car to an independent BMW specialist who identified some high/low pressure codes related to the SMG. They also discovered that the SMG fluid was extremely low and of very poor quality-it was black. So they flushed, bled and recalibrated the system. The car then drove beautifully for about 2 days. However, I noticed that once the car got warm (after about 1 hour of stop start driving), the downshift from 3 to 2 to 1 was a little bit rough – I could hear a thud but not as loud as it was before.
Problem 4: On my way back home after an initial smooth drive, I noticed that there was a lot of hesitation (lag) during shifts (especially noticeable during upshifts) – the revs would drop, but gear would not change immediately but would be stuck in neutral for a few seconds (almost 30s) before eventually shifting. Also, the cog symbol came on momentarily later that evening when upshifting from 3 to 4.
Problem 5: After having the car garaged for over 2 weeks, I took it for a drive round the block and realised the car had a mind of its own - I would shift from 3 to 4, but it would hesitate and shift to 2 instead and after few seconds jump from 2 to 4. During this period, the cog symbol and SMG Error sign would flash away like a Christmas tree. I also noticed that the SMG pump would go on for short bursts (less than 2s bursts) every few seconds. I didn't notice it doing this before so I am unsure whether this is normal behaviour.
So, I got the car towed to the independent BMW specialist. They discovered that one of the battery cells was completely destroyed and it was likely that not enough amps was being sent to the SMG unit. After changing the battery, they indicated that the bad shifts were gone and SMG fault codes gone but there was still a bit of lag shifting from 3 to 4. They indicated that a faulty crankshaft position sensor may lead to the issue. So, I authorised them to fix this but to no luck-Problem still remains. They have indicated that the most likely cause is a pressure leak on the accumulator. However, as the pump had been working hard to compensate for loss of pressure, it is likely that the pump will die soon too if it isn't already partially dead.
So the options I am left with are:
1) Replace the accumulator with the risk that the pump may fail anytime
2) Perform a manual conversion. The workshop would re-use the same transmission.
What advice would you be able to provide? In regards to the second option, has any of you had this sort of conversion done? Are there any pitfalls I should be aware of? How happy are you with the conversion? Roughly, how much should this cost?
PS: The car was for sale before the issue occurred and is still for sale (now at a heavily subsidised price due to fault)
The "ultimate driving machine" is driving me both nuts and broke.