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I'm having some strange issues with the car at the moment and thought I'd tap into the hive mind before booking into the garage.
If I'm driving along at 60-70ish in 5th or 6th gear and floor it there is a slight hesitation in the car to translate the throttle input into forward momentum and when it does begin accelerating the car feels a bit more sluggish than usual. The rev counter (during the initial flooring) jumps maybe 1-200 rpm up then straight back down before climbing relatively normally.
Is this the beginning of the end for my clutch or could it be something else?
I've done a couple of clutch [i]tests[/i]
1) Car park test in high gears will stall engine which is good
2) Driving along at say 30 put it in 5th, dip clutch, give it 5-6000 rpm, release clutch, and clutch brings engine back down to 1000rpm immediately which is good.
The car seems fine in lower gears and going up hills.
GF thinks I'm crazy as she hasn't noticed any difference in the cars behaviour in top gears whatsoever..
Any advice/comments would be most appreciated. Car is an E90 325i with 74K on the clock (bought at 47K).
Cheers
That's sounds like* the car's brainy bits, rather than mechanical.
*as a driver, not as a mechanic 🙂
Edit: Plus if was was a slippy clutch, surely you'd have noticed the smell of a thousand rotting badger carcasses.
I hadn't considered that it might not be mechanical. Interesting. It's the jump in revs (on the counter at least, as 100rpm is pretty undetectable otherwise) that has bamboozled me!
If it were clutch it would slip in all gears - probably more than in 5th.
Doesn't sound like clutch ... which may or may not be good.
Coil pack?
If your clutch was slipping you'd know. Once a dry clutch starts to fail they tend to go quickly & the slipping is obvious when provoked. IE under full torque.
Can't shed any more light than that. Possibly a sensor somewhere on its way south.
D.
dual mass flywheel??
can't remember if they were fitted on those models? Try putting car in top gear, and at about 40mph, jump on and off throttle quickly, if there is all sorts of bangs n crashed from underneath then you could have a failing DMF (or the rubber donut in the prop or engine mounts have died!)
The rev counter (during the initial flooring) jumps maybe 1-200 rpm up then straight back down before climbing relatively normally
If the ratio of engine speed to road speed is not constant then the clutch must be slipping (or you are wheel spinning). It's impossible for it to be anything else. If the clutch weren't slipping, how could the engine speed possibly increase without the road speed increasing?
I drove a car with an almost expired clutch, it did exactly that. I know it was almost expired because it was taken to a garage who removed the old clutch, saw it was almost knackered, changed it and the problem was fixed. Also only did it in higher gears, because that's when the resistance to engine torque is greatest. I drove it for a week or so and it only got a little worse, so sudden failure isn't a given.
When my clutch went I first noticed it as slightly climbing revs and a very quiet screeching noise in fifth gear under hard acceleration. Only quite a while later did it start slipping in 2,3 & 4th and failing the stall test.
Had an identical prob in the mighty Mondeo and the hive mind agreed it was the clutch/DPF/traction control/ECU etc etc ££££££££££
It was in fact...
...the tyres spinning up slightly under load. Most noticeable in damp/greasy conditions but also in the dry when provoked. Switched to some decent grippy tyres and the problem went away
Been nursing a slipping clutch For 5k .Just accelerating gently and it doesn`t slip.It has to last as ive not got 300 quid at the moment
I've just had exactly this on a Honda Civic 2.2 CDTi, its a well known fault with them up to about 2010.
In 5th and 6th it would slip under hard acceleration causing the revs to jump up a couple hundred, and if you keep your foot down for a few seconds it would suddenly catch again, revs would drop back and it would pull hard.
In the Honda's it is caused by the pressure plate warping. Its six years old and done 90k, well out of warranty, don't know if its had a new clutch as we bought it a year ago from Honda but when I got negotiating with Honda UK I ended up paying a couple of hours discounted labour, and they supplied the parts and the rest of the labour. If on inspection the friction material was worn it wasn't covered. Feedback was the pressure plate was warped and friction material well within acceptable limits.
If it was standard clutch wear, it would slip gradually in high gears at first and only stop slipping when the accelerator was released or the torque tailed off.
I'd say clutch too. It's probably a bit worn n the pressure plates getting tired my scirocco n Peugeot did the same, it's worse on a quick change.
They wouldn't slip if you just jumped on the power just on fast gear changes. If it's just started it should go on for a bit
If it was my car I'd see if it gets worse / other symptoms develop that might help the diagnosis. I am clearly not a mechanic so this could be a bad course of action
Sounds like a throttle problem rather than the clutch, I'd wait till you get a warning light and then check the error codes to see what they point to
Can't see how a throttle problem would result in a sudden rise in revs, it can only be caused by a clutch issue or wheelspin.
As molgrips said. If the revs and road speed are decoupling, in a manual transmission car, then the clutch is the culprit. Has to be (unless wheels are spinning up, which seems very unlikely). with the clutch engaged the wheels are physically connected to the crank via the gearbox so road speed and rpm will always be proportional. Can't be anything else, really.
If it were clutch it would slip in all gears - probably more than in 5th.
Seems I was [poss] wrong ... soz!
Thanks for the replies all. It's definitely not slipping at the tyres/road as it is happening in the dry on a very new set of bridgstones and the car is nowhere near powerful enough to do that.
Spooky - interesting that you had exactly the same symptoms on your Honda and it was due to a warped pressure plate.
I think I'm just going to have to nurse it for the time being as it sounds like it's going to be new clutch and DMF time... I'm thinking best part of a grand (similar work on my passat was £700).
It's pretty annoying filling up a thirsty 6 cylinder petrol and knowing that not as much of the burnt fuel is getting translated into forward motion as should be.. but the car is far from undriveable.
Cheers
Not sure you need a dmf to be honest. You don't have dmf symptoms.
I thought it was good practice to change the DMF when a new clutch kit was installed as the old DMF could prematurely wear the new clutch? I guess the garage would check though when they have it in bits and advise on the best course of action if the DMF was also worn.
It may be, depending on the car. Do you even have a DMF, on a 6cyl petrol?
It can be good practise in the eyes of the garage.
A clutch can be £600, and DMF another £600. Its not just a £10 disposable part you would change 'just in case'.
My vans clutch used to get a hammering from reversing a heavy trailer into its storage, clutch wore out but even the heavy use hadn't scored the flywheel, I opted to leave it and its been fine.
Sounds like a clutch to me, most torque involved in 5th gear hence it slips, less torque in the lower gears so its fine.