BMW Repair: bmw 528 cold temp long gear shifts., whip lash, auto electrician

Question
Hi Evan
Wishing for your advice again.

I have a 1997 E39 528 (EX Japan Model) with the automatic gearbox.  The first shift in the morning when the car is cold, the auto is held and will not shift until about 2500 rpm is reached. I understand why they have designed it that way, but I really hate this feature....it sounds terrible going down the street gently in the morning, and when it does shift, it is so abrupt it almost gives one whip lash to the neck. I exaggerate, but is there a way we can modify a temp sensor to eliminate this occurrence.  I love this car, but this feature I find very annoying, and curse the person every morning, who designed this feature. Once the car is a little warm, say 4 minutes running, the shift is back to normal, smooth, and shifting at lower rev's.

I am hoping with a auto electrician we can mod a temp sensor to think the car is a little warm, and not stone cold. Is there a chance of doing this? Or is there another way we can fool the auto? The E39 540 does not have the same problem, and/or do later models have a different system.

Thank you again for your advice. Very much appreciated, look forward to your reply.

Richard

Answer
Rich, later cars don't have this system. The 'warm up cycle' is dictated by engine temp. Engine coolant temp sensor at back of cylinder head under intake manifold. I don't recommned modifing this sensor as you will have cold start drivability complaints. Let the car warm up longer before driving if you don't like it.
-Evan