Clutch not engaging while driving.

[bryce]

Travelling to MOT today and noticed the clutch wasnt engaging properly.

I was travelling at about 60mph, 6th gear, 1800rpm. Barely using throttle as its kinda down hill. When I applied some throttle the revs were going up then crashing back down whent he clutch came in, but then it'd bump out again. Tried again in 5th (so revs were higher) and still got the same.

Dealers gonna plug her in. Thinks it could be a solonoid.

Anyone had this before?

[bryce]

Just back from dealers.

Plug it in - no faults
Check SMG pump + pressures - all OK

Only suggestion they had was that maybe Ive upset the car by running odd wheels - CSLs on front, M5 on rear - the M5 wheels stand almost 2" taller than the CSL rears.

Gonna swap back now, but the car wasnt doing its trick on the way home anyway.

Any idea lads? Warranty is out tomorrow!!

[SMD]

Pay for the warranty today!

[SpineOnABap]

Only suggestion they had was that maybe Ive upset the car by running odd wheels - CSLs on front, M5 on rear - the M5 wheels stand almost 2" taller than the CSL rears.

Interesting. Did you perform the SMG -> tyre recalibration? Like you should when you change tyres (see the handbook section on changing tyres).
If you don't it can throw the SMG into a bit of a wobbly.

It's what's often referred to as the 'SMG reset' (car into N or 0 at 40mph, pull & hold both paddles for about 4 or 5 seconds then back into gear).

[bryce]

Interesting. Did you perform the SMG -> tyre recalibration? Like you should when you change tyres (see the handbook section on changing tyres).
If you don't it can throw the SMG into a bit of a wobbly.

It's what's often referred to as the 'SMG reset' (car into N or 0 at 40mph, pull & hold both paddles for about 4 or 5 seconds then back into gear).

Ahhh, I have read that before but never paid any heed to it.

The SMG did seem to be having a wobbly as you say. Dipping the clutch while coasting at 50/60mph, then riding it back in.

Im back on standard wheels now again, but I doubt I'll can get it to do it again anyway.

Thanks for that Elliot.

(any further suggestions are still welcome!)

[SpineOnABap]

It does sound like a symptom of not doing that procedure. It tends not to matter if there's not much of a change, but if it's significant then problems occur. I had something similar when I temporarily shifted from 265 to 255 on the rear (without doing the reset). Once I'd done the reset it was ok.

It's kinda like the tyre pressure system in that it needs recalibrating when the rolling circumference changes.

[bryce]

Yeah it makes sense I suppose. The rears are significantly taller (2"), so it'd make sense that the car would get confused cos front and rear axles would be reading different speeds.

[bryce]

Well its at it again. :banghead:

This time I noticed it in third when coasting a bit around 40mph. Dis-engages and re-engages the clutch willy nilly.

Also noticed that sometimes when I change to second, its as if I dip the clutch, then clunk it back in again.

Summits not right.

[SMD]

Seems a strange one this! Have you been back to BMW about it Bryce?

[Mark CSL]

Has your csl had the relay for the smg changed they were a recall i think all my CSLs have had them changed ?


Or it could be telling you stop driving like a Girl ( not you cslgirl LOL ) AND GIVE IT THE MESSAGE :gayfight:

[glendog74]

Or it could be telling you stop driving like a Girl

I didn't want to say...! :gayfight:

[bryce]

Seems a strange one this! Have you been back to BMW about it Bryce?

Not been back since. It seems I need to source the problem myself and tell them what needs fixed :banghead:

Has your csl had the relay for the smg changed they were a recall i think all my CSLs have had them changed ?


Or it could be telling you stop driving like a Girl ( not you cslgirl LOL ) AND GIVE IT THE MESSAGE :gayfight:

Dont think the relay has been changed, I'll put it too them tomorrow. Was it to stop the above symtoms?

And yes, she gets the message once she's warmed up!

[Rags]

Why did you have m5 wheels on the rear?:hahaha:

[bryce]

Why did you have m5 wheels on the rear?:hahaha:

Just for a laugh :whistle:

Anyone got any idea?

[NZ_M3]

I don't think it's the relay - that relay controls the accumulator on the pump (i.e. that pump noise you hear when you first open the door) - it controls charging the system when it drops below a pre-determined PSI.

So it only does it in a down hill situation and not uphill and not when on flat ground? And only with part throttle??

[Bealo]

Interesting. Did you perform the SMG -> tyre recalibration? Like you should when you change tyres (see the handbook section on changing tyres).
If you don't it can throw the SMG into a bit of a wobbly.

It's what's often referred to as the 'SMG reset' (car into N or 0 at 40mph, pull & hold both paddles for about 4 or 5 seconds then back into gear).


I never knew that, I never did the SMG reset when i changed from 265 rears to 275 rears.

I'm about to put some cups on my car so i will do the reset just to be on the safe side.

hope you find out what the problem is soon bryce. :thumbs:

[mattbedford]

How do you get it into neutral at 40mph?

[glendog74]

How do you get it into neutral at 40mph?

Push the gear selector 'stick' to the left ;)

[bryce]

So it only does it in a down hill situation and not uphill and not when on flat ground? And only with part throttle??


Ermm, downhill mostly I think (Its one of them things though, hard to repeat when trying!) And yes, only on part throttle.

I have noticed if I downshift, (4th - 3rd) there's a delay before the clutch comes back in. Its as if its missed the gear. This is when free wheeling and not braking.

Doing my nut in :banghead:

[NZ_M3]

I have noticed if I downshift, (4th - 3rd) there's a delay before the clutch comes back in. Its as if its missed the gear. This is when free wheeling and not braking.


I had exactly this in my car before - except it was almost all gears, worse on the lower gear downshifts.

It turned out to be a faulty release bearing.

Our release bearing sits on a plastic sleeve on the input shaft - the design of the clutch slave cylinder and fork is such that it pushes only on one side of the fork - overtime the inner edges of the release bearing and the plastic sleeve gets worn out inconsistently left to right - causing it to catch on release. There's an aftermarket sleeve that you can buy that's made of an alloy of some sort that prevents this from happening.

I am suspecting that you might have what I had happen with my release bearing - completely worn on one side and almost non on the other, causing it to intermittently catch on release - i.e. the delay you feel on downshifts and sometimes upshift.

Lucky for me it was warranty work - free clutch kit and labour!!


Of course your situation might not be the same as mine - it could be a purely gearbox issue - the sensors might be sensing that it's hard to engage gear, thus dropping the clutch and putting it back into neutral before trying again - this happens when the synchronmesh is worn out or about to wear out. It should however register in the DME that it's had trouble engaging gears though.

Might pay to flush out that gearbox fluid and put in some new fluids and see if it helps - might even be a low fluid situation, who knows?

[bryce]

I had exactly this in my car before - except it was almost all gears, worse on the lower gear downshifts.

Thank you again. I always enjoy reading your posts as they're very informative :thumbs:

Well I was out last night for a spin, and it seems to be getting worse. Not always similar symtoms to what I described though. New ones are:

Changing up/down gear, the revs are wobbling as if it cant find the gear.
In gear (mostly third/fourth) at cruise throttle, and apply an extra half throttle I get a 'thud - thud' noise and it jolts the whole car (feeling from the rear). Again, as if the clutch wasnt in right, it takes two quick goes at re-engaging, and away we go.

What ya reckon Richie?

[bryce]

First time the 'Register has been stuck for a remedie...? :banghead:

[Mark CSL]

Bring it up and let my mtec mate have a go :thumbs:

[NZ_M3]

Thank you again. I always enjoy reading your posts as they're very informative :thumbs:

Well I was out last night for a spin, and it seems to be getting worse. Not always similar symtoms to what I described though. New ones are:

Changing up/down gear, the revs are wobbling as if it cant find the gear.
In gear (mostly third/fourth) at cruise throttle, and apply an extra half throttle I get a 'thud - thud' noise and it jolts the whole car (feeling from the rear). Again, as if the clutch wasnt in right, it takes two quick goes at re-engaging, and away we go.

What ya reckon Richie?

I am beginning to think that it's mechanical to be honest - might be a new gearbox time for you.

[bryce]

I am beginning to think that it's mechanical to be honest - might be a new gearbox time for you.


Uh oh :banghead: Just as well Ive extended the warranty.

How do I go about getting them to do the gearbox though? Ive already had them have a look at it, but they only checked oil levels, pressures and all sensors.

As always, it'll not do 'it' when I take the car in :banghead:

[NZ_M3]

I'd ask them to re-teach the clutch and reprogram the SMG shifts (2 separate things) and see if that corrects the problem.

If it's hesitating to get into gear it's does sound like a mechanical issue more than a programming issue - but you never know.

Another possibility is a bad pressure plate - these cars use a LuK self adjusting pressure plate - and occassionally when the clutch plate is worn it'd 'hunt' for the take up point - if you get the dealer to re-teach the clutch take up point it usually resolves this hunting issue (worth a try) - no fault code will show for this one (when my release bearing craped itself I had the clutch take up point reinitiated three times and SMG retaught twice before BMW finally decided to drop the gearbox to see what was wrong).

Good luck and keep us updated.