E34 540i Slow Starts - Transmission (A5S560Z | 5HP-30)

[TheEinstein]

My transmission is supposedly rebuilt. It was swapped out around 55k miles ago due to my getting the car unstuck from some snow. Around that time a BMW dealership told me, over the course of some other very bad suggestions, that my transmission was "not talking to the computer." Not talking to the ECU? Not talking to the TCU? I don't know, I couldn't get out of there fast enough. (They were trying to dry rape me for a fuel pump. I consider dry rape as trying to charge me $700 labor to change the pump. I did it, sight unseen and with no experience changing one in about a half hour. And yes that's including the time to remove the sheee@ in the trunk.)

Much time and efforts can be viewed at : E34 540i Slow Starts and Unburnt Fuel It has become a bit of a long thread in a short while IMO, but please don't hesitate to refer back. I will be.

Transmission introduction out of the way, moving on to the situation.

I have been throwing time, parts, sweat, and blood at this problem for some time now. What's happening is this, very often when leaving a stop light I get passed by 70 year olds on bicycles. Maybe not that bad, but specifically I would say I start out in 2nd, maybe even third gear. As if the car never downshifts when coming to a stop. Often times when leaving for work in the AM, the car is just sluggish. Note I seem to find all gears and it does respond much more "appropriately" when in A-S4. It's when in A-D that I experience a huge lack of power most of the time. The car just doesn't downshift when going for an acceleration, or go from stop. The transmission does seem to act better at shifting once it begins to get to operating temp, and that is usually helped along by driving in A-S4 for the first 10 minutes. Note that the problem doesn't go away, the car just acts a bit more peppy.

[BMCranky]

I know this is a really old thread - I have the same problem with my 1995 e34 540i. However, in mine, if I disconnect the MAF sensor - this thing takes off like a rocket - not quite like my G35, but much better. I bought a new after market MAF sensor, it shifts better, but it still feels like the engine just can't breath. You ever figure out the issue out with yours? I believe the dealer when they told you about the transmission not talking to the ECU - the brains in mine are definitely scrambled - can't get the mileage to show up anywhere...