Clutch problem?

Steven40181001

Steven40181001

Member
 Andover
Evening all,

Have an interesting problem with my 2003 M54 3.0i, for which I’m yet to find an answer for, following lots of searching and hunting…

The fault doesn’t appear 100% of the time, I’d say more like 70% but its most noticeable when the car is sitting around 2000rpm, under acceleration, in any gear, the revs will surge/rise quickly up to 2500-3000rpm, then drop down again and build/rise normally.
I can only liken it to keeping the clutch engaged when accelerating.
There is no juddering, or clutch slip at all and the car pulls away smoothly from stand-still.

I’m hoping it’s not a clutch replacement job but can’t think of anything else that would be causing it. I’ve already replaced the DISA internals and it’s having the VANOS rebuild next week, both being done unrelated to this issue. Clutch delay valve has also been removed.

I do have videos of the problem, but can’t upload here. If it would help to see them, drop me a PM with a phone number and I’ll them forward across to you.

Any suggestions welcome for where to look so I can give the garage (RBM) a starting point.

Thanks,
 
Are you saying that when the revs rise the car doesn't accelerate at the same time?
 
Rockhopper said:
Are you saying that when the revs rise the car doesn't accelerate at the same time?
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In a word, yes.

Let’s say at 2000rpm you floor it in third gear, the revs jump up-to 2500rpm, then drop back down and build smoothly with the engine/acceleration. The car does accelerate but the revs have this initial jump and drop.

I can only put it down to the clutch on its way out, but don’t know if there might be something else at fault.
 
Try setting off from standstill in 3rd gear with the handbrake on hard. But if the revs rise and the car doesn't accelerate then it can only be clutch slip.
 
Just a random thought to throw in there which probably will be rubbished:

The Clutch Delay Valve is designed to slow down the re-engagement of the clutch even if you jump off the pedal. Is it conceivable that it is sticking or slightly blocked, and holding a bit of pressure on the clutch, thus preventing it from engaging fully?

Also, can you actually hear the engine revs rising, or is it just the rev counter? Thinking a dodgy crank sensor, though very unlikely without causing other issues as the DME gets feedback from that too.
 
enuff_zed said:
Just a random thought to throw in there which probably will be rubbished:

The Clutch Delay Valve is designed to slow down the re-engagement of the clutch even if you jump off the pedal. Is it conceivable that it is sticking or slightly blocked, and holding a bit of pressure on the clutch, thus preventing it from engaging fully?

Also, can you actually hear the engine revs rising, or is it just the rev counter? Thinking a dodgy crank sensor, though very unlikely without causing other issues as the DME gets feedback from that too.
Click to expand...
CDV has been removed. I was hoping the fault was down to the CDV but after it’s been taken out, the fault remained.

Good question… I’d be inclined to say you can hear the engine revs rising. As I say, it’s like the clutch is still engaged when you put your foot down.
 
Worn clutch starting to slip most likely. You could try pulling the clutch pedal up with your toe and see if that helps. That could then point to a sticky master cylinder, broken return pedal spring or weak clutch fingers instead.
 
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