BMW M5 Forum and M6 Forums banner

1 - 11 of 11 Posts

·
Registered
Joined
·
29 Posts
Discussion Starter #1 (Edited)
Hello all,

My M5 has a most annoying step in power at around 1500rpm, you can't really pass through this rev range without a lunge forward. Only if you have the slightest of throttle inputs will you make a smooth transition through this point. I'm pretty sure it wouldn't have been like this from new.

It's 2001 model on a 140k. One thing to note is that it fails the vanos test, which had me thinking this may be the cause, however after this rev range it pulls nice and smooth with no issues. Both vanos were replaced at 60k (prior to my ownership). I pulled the vanos solenoids for an inspection and found the filter gauzes broken up so simply removed them. Using DIS/TIS i fired each solenoid individually and blew compressed air through each nozzle, all solenoids made the same noise/click and sounded like they were seating correctly and not blocked by filter gauze.

I think it is still on originals MAF's, although they recently got a respectable 147 L/Hr on the secret MAF test, 3rd gear WOT. There is a receipt for one CPS sensor being changed years ago, not sure which one.

The car is fully serviced, with recent plugs, fuel filter etc etc so no issues there and no codes related to vanos / CPS etc

Can anyone help me or point me in the right direction. Hopefully this is a fairly common issue.

Thanks guys

Regards
Gordon
 

·
Registered
Joined
·
991 Posts
Mine likes 2000RPM to wake itself up. The powerband, I believe, begins here (havn't had her dyno'd). It's very manageable however, you say you can't control the lunge without really tip-toeing through the rev range?
 

·
Registered
Joined
·
29 Posts
Discussion Starter #3
Hi,
The only way to control it is to pass slowly through 1500 RPM, if in say 1st or 2nd, then apply the desired throttle input. If i take of as normal in 1st and give it WOT at say 1k RPM, when it reaches 1500 RPM there is a lunge forward as the power comes in so makes for a very abrupt take off. The misses is always complaining about my driving but taking off from a stand still or junction with a decent amount of throttle always results in this lunge.

I know there are many posts about jerky throttle etc but this isn't so much jerky more like sudden stepped increase in power. I've never driven any other M5's so nothing to compare it against.

Hoping more people will chime in with their experience.
 

·
Registered
Joined
·
29 Posts
Discussion Starter #5 (Edited)
Here are my Vanos results. Tried the test time and time again but get more or less the same results. Holding the revs manually higher than the predetermined 1500rpm doesn't make any difference either. I think i read on here somewhere that holding the revs higher sometimes managed to pass the test but unfortunately not in my case.

Do you reckon this could be the cause of my step in power?…

Cheers guys.
 

Attachments

·
Registered
Joined
·
29 Posts
Discussion Starter #8 (Edited)
I've read on other posts that updating the DME software improved, if not eliminated jerky throttle response. I don't think this issue comes under jerky really but will phone the dealerships tomorrow to see if they have a record of it been done in the past.

Would updating DME software overwrite a remap i have at the moment?
 

·
Registered
Joined
·
12,890 Posts
Would updating DME software overwrite a remap i have at the moment?
Yes.

If you confirm that all mechanical issues have been addressed, then it is software. I remember earlier versions on my car, it had some "kangarooing" in 1st gear mostly. And that was with an early Dinan upgrade.

It didn't get addressed until I got PC software, which was fabulous. Better power, better drivability, no more jerkiness.

The same is true of my current alpha N, which deletes the MAF's. Super smooth power delivery, great cold and hot start, never any issues.

Software can also be customized somewhat, like remember last setting for "sport", deleting rear O2 sensor warnings, etc (if that is what you want). Software upgrade is worthwhile. Tons of posts discussing it, and virtually everyone with Evolve software has been pleased. Other software makers deliver a good product, read the reviews and then you can make your own decision.

Regards,
Jerry
 
  • Like
Reactions: Go-M5-Go!

·
Registered
Joined
·
29 Posts
Discussion Starter #11
Hi there,

No mate i never looked into it, the car was off the road there for the last 8 months as i've been using a 2004 RS6 that i bought.

It's legal now back on the road but i've only been driving it short distances as the diff seals need doing. I've bought the seals and oil so just need to get the finger out now.

I would like to get to the bottom of it though as it's most annoying.

I have some dealership receipts for timing checks that were done in the past so hoping that's not the issue, can't remember what mileage the checks were done, i think around 70k, it's now on 141k.

On DIS it does fail it's Vanos test on both banks, but when i removed the boards all solenoids were clicking fine and the remainder off the gauze filters removed. 2x complete vanos systems were fitted at the same time the timing checks were done.

I only have 1 receipt for a CPS sensor being replaced so perhaps the 3 remaining ones are original, maybe that's were the fault lies, however i am not getting any Vanos related codes?

Hmmm, what to do?.....
 
1 - 11 of 11 Posts
Top