Q: M5 cold start bogging. - The Unofficial BMW M5 Messageboard (m5board.com)

emiliowu · 17th February 2006, 21:42

Hello everybody: New owner of a CPO, Le Mans blue, 2003 M5 with 19,000 miles. This is my fourth BMW but, it is my first M5. Question: Driving after a cold start produces bogging and hesitation from the engine until the engine warms up. Following the instructions from the manual, it says to drive the car right after the engine starts, at low speeds. I have been doing this with my other BMWs but none of them do what the M5 does, which is, really, a reluctance to accelerate beyond 1,500 rpm. I have a 2002 530i that I drive everyday and it accelerates smoothly when driving and warming up the car.

IS THIS NORMAL IN THE M5 ??

Thank you in advance.

Clem · 17th February 2006, 22:28

It's normal in mine.

We're just coming off of a cold snap -27*C with a windchill of -40*C (weather you'll HOPEFULLY never see in Florida)

I usually will let my beast warm up till the first tach light goes out (4000-4500 rpm) From there I'll drive without exceeding 2000-2500 RPM until she's fully warm. It will usually bog and hesitate SLIGHTLY until the tach lights go out from anywhere between the 4500-5500 range.

sjdennis · 17th February 2006, 22:36

Since you are in Miami, it is probably not that cold. I'm in California and had the same problem. Turned out to be the MAFS (Mass Air Flow Sensors). If your car is CPO the dealer may cover it if they acknowledge there is a problem.
My Dealer kept telling me this is normal, so I bought a pair of MAFS from the group buy, replaced them myself, (pretty easy) and the problem went completely away.

Good luck with your dealer. If you want to get the MAFS yourself, check the group buy forum. I think DavidS may still have some left.

Dennis

chunpng · 17th February 2006, 22:50

It does sound like the MAFs, but in a 2003 with only 19k miles, that's disconcerting. My 2000 had slight hesitation at the beginning. The Power Chip totally cured that.

CP

Michael_s · 17th February 2006, 23:06

A little hesitation is normal.....should not be too extreme...If It is, have the dealer look at it...did you buy it from Braman? Is it white? If so, I know the car....

gra8fuldd ed · 17th February 2006, 23:18

Michael:

You may want to Re-Read this man's 1st sentence.

He says it's a 2003 LeMans BLUE ... Not WHITE.

Do you still know the car??

Sorry ... I do the same once in a while as well.

Have a swell one.

Anzir · 17th February 2006, 23:56

Sounds just like my issues and replacing the MAFS cured it for me. Do a search for MAFS engine hesitation and you'll find tons. My car was seriously hesitating and then all the sudden within 1/2 mile it would just "wake up." Very weird...

emiliowu · 18th February 2006, 02:50

Thanks everybody !!
I'll see what the dealer says about it and bring the MAFS subject. Otherwise, I'll be looking for new ones. Thanks again.

emiliowu · 18th February 2006, 02:57

I saw the white car ! It was in excellent condition (only 3K miles) but, it was never title so it does not come with the extended guarantee from BMW (It is not a CPO). The car was in the fleet of BMW cars that they used to lend for magazines tests (Road & Track, Car and Driver etc.). I negotiated with them and their lowest selling price was $59.8K.

EW.

gsfent · 18th February 2006, 11:47

Quote:

Originally Posted by emiliowu

Thanks everybody !!
I'll see what the dealer says about it and bring the MAFS subject. Otherwise, I'll be looking for new ones. Thanks again.

Some slight hesitation when cold is normal. Try the sport button, that helps a little. Also, the stock programming is weak. Better ECU programming is available. When I upgraded mine, 95% of the cold stumble disappeared.
For MAF's test, dealer will only do a static (at idle) test. You need a dynamic (under load) test. Do a search, if you unlock the on board computer (OBC), you can run a dymanic test on the MAFs.
Good luck and welcome!!!

Regards,
Jerry