Strange slip/rev jump

[evopilot]

Anybody ever hear of this in a A6?

Whilst accelerating say around 3000/4000 rpm or higher the car would temporarily slip/jump revs loosing acceleration for about 1000rpm then re-grip causing the revs to fall slightly only to then continue to pull to redline, also i noticed during this slip/jump period the screen between the revs and speed dials would loose the gear indicator. Primarily happens in 3rd, 4th and 5th that Ive noticed.

 

There was one thread i found online from another forum which sounded like my issue but nobody replied to the poster.

 

I don't believe its a full worn clutch slip for two reason,

1. In my past experience a worn clutch that was slipping would slip at a certain RPM and would slip revs into the red line without re-gripping

2. The clutch was done within the last 20,000kms

 

No faults being reported on the car electronically

[evopilot]

also to add a little more information...

It doesn't slip at the same rpm each gear its more random and sometimes it wont slip at all going through the gears

[Magnet]

Hello Andrew,

Manual? 
Kind regards,

Gareth. 

[evopilot]

1 hour ago, Magnet said:

Hello Andrew,

Manual? 
Kind regards,

Gareth. 

Manual but feels like an automatic gear change when it happens

[Steve Q]

The two things I'd be looking at here is getting the clutch/duel mass flywheel looked at along with a diagnostic check if the clutch isn't the cause. 

[Magnet]

Hello Andrew,

I’m a little unsure from your description whether this is a ‘misfire’ - engine momentarily loosing power, or whether it is indeed associated with clutch issues. The latter sounding more likely. 
No offence meant, but it appears you drive this car ‘enthusiastically’ ( polite), and accelerating after 3000/4000 rpm and continuing to rev. it to the limit. Even if the clutch ‘was done’ - exactly what? - in the last 12k miles, it’s life will depend on what was done, the quality of components used, and the way in which the car has been driven. 
On a brighter note, this puts me in mind of the great, late Welsh comedian - Tommy Copper, who went to the doctor, and said his arm hurt when he bent it, to which the doctor replied ‘ Well don’t bend it then’! 
Kind regards,

Gareth. 

[Stevey Y]

11 hours ago, evopilot said:

Manual but feels like an automatic gear change when it happens

Hi its the clutch master cylinder holding off, I had it on my car they are Cr@p plastic thing and the seals swell if the brake fluid is a bit past its change date, mine went about 3 months after I had my clutch changed the reason the symptoms are random is because it is all regulated by the torque bite depending which gear you are in say 3rd at 1500 rpm as soon as you push the throttle as the torque increases the the thing will briefly slip then grip, do that for too long and it does wonders for the driven plate wear, quite a bit of stripping down under the plastic scuttle to get at the cylinder and about two hours graft in all, did mine and used an O.E. cylinder from TPS as my mechanic told me the Febi units were failing quite frequently, bled everything with fresh fluid and not had a problem since, BTW Ford are having a real problem with this with Transits and now insist you change the clutch master when you put in a new clutch.

[evopilot]

3 hours ago, Magnet said:

Hello Andrew,

I’m a little unsure from your description whether this is a ‘misfire’ - engine momentarily loosing power, or whether it is indeed associated with clutch issues. The latter sounding more likely. 
No offence meant, but it appears you drive this car ‘enthusiastically’ ( polite), and accelerating after 3000/4000 rpm and continuing to rev. it to the limit. Even if the clutch ‘was done’ - exactly what? - in the last 12k miles, it’s life will depend on what was done, the quality of components used, and the way in which the car has been driven. 
On a brighter note, this puts me in mind of the great, late Welsh comedian - Tommy Copper, who went to the doctor, and said his arm hurt when he bent it, to which the doctor replied ‘ Well don’t bend it then’! 
Kind regards,

Gareth. 

the word redline is mentioned and you tip toe around "no offense" being smart then try to polish off with a joke... You have assumed allot with little to no facts.

The car holds grip after the slip never once does it mention i hit the limiter once let alone "enthusiastically". Keeping a description short but on point is easier then stating 6543rpm or a point i change gear and cramming too much detail into a post

[evopilot]

1 hour ago, Stevey Y said:

Hi its the clutch master cylinder holding off, I had it on my car they are Cr@p plastic thing and the seals swell if the brake fluid is a bit past its change date, mine went about 3 months after I had my clutch changed the reason the symptoms are random is because it is all regulated by the torque bite depending which gear you are in say 3rd at 1500 rpm as soon as you push the throttle as the torque increases the the thing will briefly slip then grip, do that for too long and it does wonders for the driven plate wear, quite a bit of stripping down under the plastic scuttle to get at the cylinder and about two hours graft in all, did mine and used an O.E. cylinder from TPS as my mechanic told me the Febi units were failing quite frequently, bled everything with fresh fluid and not had a problem since, BTW Ford are having a real problem with this with Transits and now insist you change the clutch master when you put in a new clutch.

This is a brand new OE master cylinder Steve, involved during sorting my older issue.

The slip had started before that although i completely forgot about it then the F194 issue came in which includes a new cylinder from Audi and the slipping started again no more then 3-5miles into its first road test after fixing the previous issue 😕

[evopilot]

If its the clutch its the clutch it is what it is, ive just never experienced a random slip of revs in all my years with cars.

With clutches going its alway been either

1. Clutch pedal drops to the floor

2. Albility to change gear with engine on stops

3. Clutch slips at a similar RPM each gear and would redline without gripping if you held you foot on accelerator

 

So this is new to my experience if this is a symptom

[Magnet]

Thanks Andrew. 

[Stevey Y]

20 hours ago, evopilot said:

This is a brand new OE master cylinder Steve, involved during sorting my older issue.

The slip had started before that although i completely forgot about it then the F194 issue came in which includes a new cylinder from Audi and the slipping started again no more then 3-5miles into its first road test after fixing the previous issue 😕

Hi its one of two things, if the whole brake system is not bled with the cylinder the symptoms will return, get the car up in the air remove the belly pan and there is an inspection cover on the bottom of the  bell housing pull it off and have a good look inside for oil misting/oil there are two real nasty oil seals in there one inside the slave cylinder and one on the n/s driveshaft which runs across the box to the diff the seal there is prone to leaking gear oil as well, if its as dry as a bone in there its definitely the pressure plate going weak, how many miles has the car done, will post some pics that my be of use in understanding.

Steve.

[Stevey Y]

23 minutes ago, Stevey Y said:

Hi its one of two things, if the whole brake system is not bled with the cylinder the symptoms will return, get the car up in the air remove the belly pan and there is an inspection cover on the bottom of the  bell housing pull it off and have a good look inside for oil misting/oil there are two real nasty oil seals in there one inside the slave cylinder and one on the n/s driveshaft which runs across the box to the diff the seal there is prone to leaking gear oil as well, if its as dry as a bone in there its definitely the pressure plate going weak, how many miles has the car done, will post some pics that my be of use in understanding.

Steve.

Hi here are the pics of my box out, the driveshaft seal goes in hole in the gearbox diff housing I also included a picture of the reciprocating part of the diff, the exploded diagram shows the other possible contender marked in yellow that fits between radius shaft and the inner bore of the slave cylinder, the pressure plate and driven plate are industrial quality with regard too gripping there are only three things that cause slip, clutch master, contamination or just good old wear

[evopilot]

my wife was driving the other day and as we were going up the road she got a clutch malfunction you can continue driving warning and a flashing coil light 😕 ill have to conceed the clutch is going again, hard to swallow as its not long done.... i can only assume the person that did the clutch before only changed the clutch and not the flywheel etc.

@Stevey Y have you priced the clutch for one of these in the UK? i am being told by all auto parts places over here its a main dealer only clutch kit, about €1000 for the flywheel and €600 for the clutch kit plus vat on both them prices too 😕

[Stevey Y]

3 hours ago, evopilot said:

my wife was driving the other day and as we were going up the road she got a clutch malfunction you can continue driving warning and a flashing coil light 😕 ill have to conceed the clutch is going again, hard to swallow as its not long done.... i can only assume the person that did the clutch before only changed the clutch and not the flywheel etc.

@Stevey Y have you priced the clutch for one of these in the UK? i am being told by all auto parts places over here its a main dealer only clutch kit, about €1000 for the flywheel and €600 for the clutch kit plus vat on both them prices too 😕

Hi the bar stewards at Audi have not yet released the patent for the clutches in the UK but my garage managed to get all in from TPS for 1450.00 plus about another £30 quid for the seals driveshaft/slave cylinder, the clutch driven plate and pressure plate have recently appeared on eBay circa £280-320 from Lithuania, the flywheel at sub £500 all genuine parts, the slave cylinders anything between 90-150 pounds, its worth looking at European sites as you are still in it judging by the euro quotes, I found my clutch £400.00 cheaper on a German site but was excluded as the UK is now out and they won't ship to Essex.

On another note I have recently found out from my new friend that most of the manual versions of our car suffered with a problem which was designated DEW, in other words a build up of moisture in the bell housing which would cause random slippage, the cure apparently was take it for a long drive sixty miles plus and get it nice and hot, so before you start throwing money at it try that, the Dew build up is caused by short journeys and lots of town driving, if it works its cheaper than a new clutch.

Steve.

[evopilot]

Finally got around to removing the gearbox in my garage last week... the cause of the slipping was a failed slave cylinder leaking fluid over the friction plates and in the box itself causing issues. I decided to replace the clutch too while its all stripped out. LUK now have a listing on there website for our cars needless to say its wrong as my local motor factors found out. Flywheel is tired on my car but the clutch was relatively fresh with very little ware

 

OCS105266L - Flywheel

OCD141015E - CLutch/pressure plate

For reference

[evopilot]

Right, this is proving to be a right pain.....

Clutch, Flywheel, and slave cylinder were all swapped for new parts and ITS STILL doing this weird issue

 

To recap now it's fine when on normal cruise and partial throttle there is no issue at all its smooth as they day it rolled out of the dealership, the problem kicks in under heavy acceleration say when over taking the power comes in and you can feel the turbo pull the car then it looses power, stops pulling, the revs jump up 500-1000rpm and the car comes back in, naturally the turbo is no longer pulling as its lost pressure but if i keep my foot accelerating you can feel the turbo coming back in again 

In all the years Ive dealt with clutch slipping it would always loose grip at a certain RPM and keep spinning after that RPM that being said i still replaced the clutch and flywheel on this car last week and changed the slave cylinder whilst it was all stripped out for the sake for €150 it seemed like a good move.

So now im nearly 2k deep in parts cost and the problem remains after the new clutch & flywheel.

I am at a lose trying to think whats mechanical, whats controlled by sensors, cold it be a faulty LSD im running out of ideas as im used to working on JAP cars

 

[gsmdo]

7 hours ago, evopilot said:

To recap now it's fine when on normal cruise and partial throttle there is no issue at all its smooth as they day it rolled out of the dealership, the problem kicks in under heavy acceleration say when over taking the power comes in and you can feel the turbo pull the car then it looses power, stops pulling, the revs jump up 500-1000rpm and the car comes back in, naturally the turbo is no longer pulling as its lost pressure but if i keep my foot accelerating you can feel the turbo coming back in again

OK - don't bite my head off - but from your description, this sounds suspiciously like a fuel blockage. Sudden loss of power; stops pulling; blockage clears; revs increase... 🤔

[evopilot]

Here is a video i took earlier in 4th gear.....

Gets to 2400rpm and jumps to 3100rpm

Falls back to 2600rpm and we go on our way again as if nothing happened

During the jump you can see the selected gear notification disappears during the jump and comes back when the revs have come back down.....

This is what i mean about it being a strange jump as in my opinion a clutch on the way out would slip at 2400rpm and keep slipping not stop slipping

[evopilot]

On 10/29/2022 at 9:31 AM, gsmdo said:

OK - don't bite my head off - but from your description, this sounds suspiciously like a fuel blockage. Sudden loss of power; stops pulling; blockage clears; revs increase... 🤔

thanks buddy i might run her with VCDS and see if the fuel system is showing anything odd, at this stage its worth a try

[juju]

On 11/2/2022 at 12:37 AM, evopilot said:

thanks buddy i might run her with VCDS and see if the fuel system is showing anything odd, at this stage its worth a try

Hi evopilot,

I'm having the same problem did you manage to get to the bottom of yours yet? changed the fuel filter did not work also done an ECU update and this did not solve it, any help would be greatly appreciated.  

[evopilot]

ill send you a PM

[JHC]

What was the issue ? Mine is doing it !

[evopilot]

this issue ended up to be a failed clutch slave cylinder leaking inside the gearbox, gearbox off, clean like hell and clean some more and replace the part. sadly it would be ver hard to inspect this issue with the gearbox on 😕

[juju]

My issues ended up the same failed clutch slave cylinder leaking gearbox oil leaking onto the clutch causing the slipping. Replaced the clutch, flywheel and slave cylinder, found it hard to source parts outside of main dealer which was at least double the cost €€€€.

This is not a issue that could be diagnosed or inspected without the removal of the gearbox !!!