Acceleration Issue - The Unofficial BMW M5 Messageboard (m5board.com)

supakappa · 22nd January 2008, 03:03

Purchased my 2003 M5 in November with a clean PPI and 44,000 miles. Added Shark Injector software a couple weeks later. When sprinting off, 1st and 2nd are full of pull and power. However, when hitting third, the tach will often race up to 6 or 7 with little or no acceleration evident, and if I drop into fourth it will just race right up to 6 or 7 with no pull again. The gear is fully engaged, and if I let off and then reapply the accelerator, the power often comes back. Sometimes it runs great from 1st-5th, but it's becoming more apparent. Is it shift points? Is it the software? Is the tranny slipping? I recently replaced my O rings, but that is all. Any help is appreciated.

Cantresjr · 22nd January 2008, 03:14

sounds like you need a new clutch. have you noticed a foul burnt smell after those runs?

chowdah · 22nd January 2008, 03:55

Unfortunately, a clutch inspection isn't typically part of a PPI as it requires removal of parts. A test drive would have been your best bet to seek it out.

It's not that unusual, given the mileage (some people get double that). It may tell you something about the "quality" of someone's shifting, or that you have a rear main seal leak, etc.

Lots of info on this topic available by search. Good keywords: "slipping rpm"

supakappa · 22nd January 2008, 04:01

Thanks, no foul smells. I'll check into the "slipping rpms" posts as well. I replaced a clutch in my old M3, and their was a distinct "whirring" sound when engaging the clutch, but no slipping rpms ever.

Cantresjr · 22nd January 2008, 04:21

whirring sound is more likely a bad throw out bearing.

Eric Giles · 22nd January 2008, 04:47

It's definitely time for a new clutch. Continuing to drive the car with the clutch slipping like that will also damage the flywheel, which in turn means it needs to be replaced also. I am going thru a clutch replacement right now on a '00 M5 I purchased just over a week ago. Since you have done one before, you will find the hardest part being the exhaust removal-it is very heavy and BIG! That part will definitely take two people to remove-and to reinstall later. The transmission removal is very easy, as unlike on most of the 6 cylinder models, the transmission bolts are very easy to access on the V8.

JohnAnthony · 22nd January 2008, 05:17

we need a new "clutch-smiley"...where it looks like its dieing or its had it; a mix off these into one singel expression:

:ka ffe:

you're clutch has been going for a while, i remember reading another members post about how this happened to them on a downshift from 6th to 5th...i would assume the lower the gear the more worn the clutch is since it's pushing with less resistance

richie_rvf · 22nd January 2008, 13:35

Definitely sounds like your clutch.

If you don't want to ruin the flywheel get the clutch done asap - it may already be too late though.

Richie.

jclyman · 22nd January 2008, 19:29

I vote for tranny slipping ... Happens ALL the time on mine ... Well, no, not really.

Seriously, it IS your clutch going south.

If it were me, and I know it is not, I would delay the clutch replacement ... What? Yes.

It's time to learn how to shift! The clutch must be fully engaged before applying ANY gas. That means your left foot OFF the clutch pedal BEFORE your right foot drops the hammer! NOW, is the time to get it right! The M5 is NOT a dragster, it is a practical, VERY FAST 4-door sedan. Practice, practice, practice ... until you get it correct ... and smooth. Then replace the clutch AND FLYWHEEL. I suspect the flywheel is cooked by now, if you have seen your revs reach 6 or 7K (with the clutch slipping) multiple times. LEARNING TO SHIFT PROPERLY IS BEST PERFORMED WITH A WEAK CLUTCH ... and, yours is.

I'm not trying to be an @sshole, 'cause I already am, but telling it like it is.

supakappa · 22nd January 2008, 19:40

I appreciate the advice, no offense taken. I'm a fairly competent shifter, however the previous 44,000 miles of possible abuse/misuse prior to me are in question. I contacted the dealer (American Service Center) in regard to the limited warranty, and I'm hoping the clutch will fall under the 3 month/3000 mile warranty. It lists "Transmission and Differential" as a covered system. My fingers are crossed that a clutch falls under this. No way I burned the clutch out in 1,500 miles.

jclyman · 22nd January 2008, 19:53

Quote:

Originally Posted by supakappa

I appreciate the advice, no offense taken. I'm a fairly competent shifter, however the previous 44,000 miles of possible abuse/misuse prior to me are in question. I contacted the dealer (American Service Center) in regard to the limited warranty, and I'm hoping the clutch will fall under the 3 month/3000 mile warranty. It lists "Transmission and Differential" as a covered system. My fingers are crossed that a clutch falls under this. No way I burned the clutch out in 1,500 miles.

Oh, boy, tough call ... I'm guessing the clutch might be exempt from coverage as it is not part of the transmission, and it's a CONSUMABLE. Best approach is to argue that it was bad from the time you TOOK POSSESSION of the car (very likely, by the way), it just took a few miles to confirm. Good luck.

However, I would still recommend practice with the car as it is now. Competent is not perfect, but it is an excellent start.