Car juddering violently when idle/ revs hunting

syed123

Registered User
Hi guys

Had my a4 272 for 3 years now and had a tdi tuning box on for most that time.

I recently noticed when starting the car first thing in the morning the car started juddering violently and the revs were hunting.

The start stop fault came on and the car cut out.

It happened again just yesterday and I quickly reversed out of the drive before it cut out again and carried on my way and noticed nothing different about how the car drove.

I'm worrying about what it could be? I've done 56k miles and the last service was done at 41k

Done mostly motorway miles since and doing a service in a few weeks.

I'm thinking a possible injector fault as a recent diagnostic showed that my v6 wasn't firing properly.

Spoke to tdi who said this fault can be possible due to the box changing the fueling etc.

The only different thing I've done recently is flash my gearbox with the tmc software as the car recently did a software update and that overwrote the file.

It does say in the instructions that the cars revs may hunt whilst installing but my cars symptoms showed up a few weeks after the installation!

Either way my warranty will be up in August so need to act soon!

Any others experienced this issue?
 

syed123

Registered User

WesT-gefül

Well-Known Member
Bronze Supporter
Thanks for that, saw this post earlier but not sure if it's the same issue as the OP didn't mention any juddering/ revs hunting.

Gearbox judder or lack of fuel? Could be the box no? A diesel is more sensitive to lack of fuel due to compression. Can you Re flash and see if it resolves.
 

syed123

Registered User
Gearbox judder or lack of fuel? Could be the box no? A diesel is more sensitive to lack of fuel due to compression. Can you Re flash and see if it resolves.

There was fuel in at the time, over half a tank. I was literally parked at idle and the revs were jumping as if I was revving the engine. Then the dreaded judder sound. I don't think it was the gearbox.

I don't want to flash the gearbox again however as the whole adaption process is really annoying (I've flashed quite a few times as I didn't feel a difference)

The fact its happened more than once is what worries me as the v6 tdi is meant to be Audi's most reliable engine from what I've heard..

So it's looking like a trip to Audi or il ask tdi tuning if they have any insight into the issue
 

cuke2u

Registered User
I assume you have tried running the car without the box physically connected?
 

syed123

Registered User
I assume you have tried running the car without the box physically connected?

Yeah I have, for about a week or so and no shaky idle.

The thing is the second judder came a few weeks after the first so it's hard to pin point whether it's the box or not. I think il ask tdi tuning
 

cuke2u

Registered User
Might be worth it, could be the box or its loom/connectors are faulty...
 
A

And1

Guest
Yeah I have, for about a week or so and no shaky idle.

The thing is the second judder came a few weeks after the first so it's hard to pin point whether it's the box or not. I think il ask tdi tuning
HI syed did you sort the issue out with the judder? I can't seem to get mine running well I've had a number of different maps from tdi tuning and seem to get a diesel knock/pinking sound on all the maps
 

syed123

Registered User
HI syed did you sort the issue out with the judder? I can't seem to get mine running well I've had a number of different maps from tdi tuning and seem to get a diesel knock/pinking sound on all the maps

Hi,

I went in last week and they've put a brand new map on, it's excellent and even better than before. It's not as aggressive as before but much smoother and easier to live with day to day.

The judder has gone and also any diesel knock. It's running quieter now too.

Contact tdi tuning and mention that I told you about the update, they know me quite well.

Thanks
 
Top