Revs when changing down gears

Got a problem with your BMW 1 Series? Post your car problems here and seek advice from fellow car owners.

Moderators: Rich196, babybmwadmin, marco_polo, Producethis, Lambster

Post Reply
drofmum
Junior Member
Junior Member
Posts: 5
Joined: Wed Jul 11, 2018 5:05 pm

Revs when changing down gears

Post by drofmum » Wed Jul 11, 2018 5:20 pm

Hi
We have recently purchased a 2016 BMW 1.8d. When changing down gears (usually 4th to 3rd and 3rd to 2nd) with foot on clutch and off of the accelerator we seem to get a little rev that can go up to 3 on the rev counter. The car is under warranty and is in a BMW garage at the moment for a check. However they have telephoned to say that they can find no fault on the computer. The mechanic is going to take it for a run tomorrow to see if it happens with him. We are a little concerned as it doesn't happen all of the time and he might not experience the problem and just dismiss it because the computer says no! Any ideas what this might be that we could put to the garage to check out?

Many thanks in advance.

User avatar
Red5
Too Much Time To Waste Member
Too Much Time To Waste Member
Posts: 5688
Joined: Thu Jan 22, 2009 2:47 am
Location: Surrey

Re: Revs when changing down gears

Post by Red5 » Wed Jul 11, 2018 6:01 pm

Sounds like automatic rev matching, which is designed to help change down, without upsetting the car, or adding wear to the clutch.

In a manual car, you’re supposed to do this yourself when you downchange.

The ‘blip’ just before the clutch is re-engaged, stops the plates contacting at differing speeds. This is what gives the horrible lurch forward, or slurring feeling.
Gone
Tasty 130i
Very fast 135i
Volcano Grey Macan SD
Carmine Red Cayman GTS + LSD

Red5 & Semerka's Stable
Midnight Blue Macan Turbo + PTV and more
GT Silver Cayman 718 GTS Manual



(Team Rob)

drofmum
Junior Member
Junior Member
Posts: 5
Joined: Wed Jul 11, 2018 5:05 pm

Re: Revs when changing down gears

Post by drofmum » Wed Jul 11, 2018 6:26 pm

Thank you for your quick reply Rob5. Was a bit concerned because it can go up to 3 on the rev counter which seems a little excessive and sounds even worse! We have always had manual gear cars and also a couple of BM's and this has never happened before. In your opinion (I know it's not easy to diagnose without seeing it) should we be concerned that it is a fault somewhere or something harmless that is designed to alleviate clutch wear and stress on the car as you kindly said.
Thanks again for your help

User avatar
Red5
Too Much Time To Waste Member
Too Much Time To Waste Member
Posts: 5688
Joined: Thu Jan 22, 2009 2:47 am
Location: Surrey

Re: Revs when changing down gears

Post by Red5 » Thu Jul 12, 2018 1:21 pm

Really need a much more exacting explanation, with perhaps even a video.

I would think that BMW would not book the car in to inspect it for doing rev matching.

During rev matched changes, the size of the blip varies.
If you change down to 2nd at 20mph, it will be very small.
If you change to 2nd at 40mph, it will be pretty large, as your roadspeed is higher.

The blip could be up to the redline and ot would be normal.


Please also describe exactly how you normally change down.
Gone
Tasty 130i
Very fast 135i
Volcano Grey Macan SD
Carmine Red Cayman GTS + LSD

Red5 & Semerka's Stable
Midnight Blue Macan Turbo + PTV and more
GT Silver Cayman 718 GTS Manual



(Team Rob)

drofmum
Junior Member
Junior Member
Posts: 5
Joined: Wed Jul 11, 2018 5:05 pm

Re: Revs when changing down gears

Post by drofmum » Thu Jul 12, 2018 11:11 pm

Many thanks for your reply Red5. It is difficult for me to describe how we change down gears but both myself and my partner have experienced this issue. We are both pretty careful drivers and never change down to 2nd at high speed as in your example.
BMW have told us that this is normal and attributes this to the automatic matching as you have previously kindly described. They came to this conclusion after the mechanic took the car for a test drive, but, I suspect, as this issue happens at random, he may have only experienced the slighter additional revs, if he experienced the issue at all! The car has also been on the computer which has shown no faults.
We are a bit on the crinkly side at 59 & 61 years but would like to think that we are not completely gaga. I fear however, that the mechanic and the computer may think otherwise.
Having never owned a car that has automatic matching before we have nothing to compare with so, we have to accept that this is normal but we certainly don’t like it. We have around 10 months left on the manufacturers warranty so will keep a close eye on this issue. Other than this the car is lovely to drive.
Thanks once more for taking the time to reply and for your help.

Blind Pugh
Too Much Time To Waste Member
Too Much Time To Waste Member
Posts: 8638
Joined: Wed Aug 28, 2013 6:36 am

Re: Revs when changing down gears

Post by Blind Pugh » Fri Jul 13, 2018 8:38 am

If you switch to sport + mode it should disable auto rev matching feature.
Fettled M135i EB AT - gone but not forgotten !
AW M2 DCT

drofmum
Junior Member
Junior Member
Posts: 5
Joined: Wed Jul 11, 2018 5:05 pm

Re: Revs when changing down gears

Post by drofmum » Fri Jul 13, 2018 12:39 pm

Thanks for your reply Blind Pugh. We thought it might be something to do with this sports mode thing and have tried all of the modes but it still happens. To be honest we would have been happy with a basic flipping car but having travelled around 500 miles round trip to view and buy another model we were told by the dealer that it was no longer available and that this was the only similar that they had! Having said that, it is a lovely car and we are very happy with it apart from this niggling little worry that all is not quite right and might go expensively wrong once the warranty is up.
Thanks again for taking the time to reply.

User avatar
GeoffCollins
Enthusiastic Member
Enthusiastic Member
Posts: 1014
Joined: Mon Feb 01, 2016 11:02 am
Location: Around London
Contact:

Re: Revs when changing down gears

Post by GeoffCollins » Fri Jul 13, 2018 1:17 pm

Try taking traction control off, this should definitely turn it off, if it doesn't it's a problem, hold down the DSC button for about 10 seconds and it should turn the assists off completely, not sure it turns off the blips in sport plus
M135i (2014 Manual) - Custom Stainless Exhaust, JB4, BMS Intake, M4 LCA, M4 Front Pads, MeisterR Coilovers, Cades Bern Wheels, Reiger Diffuser, Maxton Splitter, Double Slat Grills, M4 Mirror Caps

drofmum
Junior Member
Junior Member
Posts: 5
Joined: Wed Jul 11, 2018 5:05 pm

Re: Revs when changing down gears

Post by drofmum » Fri Jul 13, 2018 3:37 pm

Thank you very much GeoffCollins for taking the time to reply we will certainly try this.

Post Reply

Return to “BMW Problems”