Annoying Diesel like noise on light acceleration

[Leighspain1975]

Hi Guys

I’m driving an Audi A7 2012 3.0tdi Quattro 245cv.

I have this diésel like ticking noise when accelerating slowly. It increases with the rpm and may be present at higher revs but road noise makes it’s quiet.
I recently had all chains etc done so chain rattle is completely ruled out.
The car still runs well but I notice a little more rough than normal and car judders when it changes gear.

The weird thing is that once every 20 starts more or less the noise is completely gone and the Car is a smooth as silk with no judders or noise or anything. Only to stop the Car start again and boom their it is again.

I’m thinking electrical possibly an injector issue?. Not necessarily faulty injector but electrics involved with it.

Any help would be great ?.

Thanks

 

[Rhyso]

Does the car idle ok?

When i had an injector go it would struggle to maintain idle when stationary

If you can find someone with VCDS you can log the injection values

 

[Leighspain1975]

Thanks for the reply Rhyso

It’s been checked through VCDS and Car is as clean as a whistle not a single fault. Injector values are all within their limits. The annoying part is it won’t make the noise when idling and only seems to do it under load. I have two mechanics say two different things. One says it’s starving of air and the other says it’s a possible injector that won’t show up on VCDS if electrical fault. I know when the car will do it because when it starts it will slightly vibrate and won’t seem smooth.

 

[audiA6Q]

Hey, I'm experiencing something similar with my A6 3.0 TDI, 2016. A diesel-growling sound on acceleration and a non-silky-smoth ride in general. And as you say, sometimes it runs perfect, nice and smooth. Did you get to understand what the problem was?

 

[Seanchadwick2k3]

Shot in the dark here but I noticed my tractor like Mondeo produced a noise like this after blanking the egr?

 

[Leighspain1975]

Nah, mine still doing it.
Literally just today it’s in a good mood and everything is super smooth, acceleration, gear changes etc. The engine also seems much more quiet and refined it also sounds different ?.
But tomorrow it will go back to Sh&?!;t again I’m sure.
I’m almost starting to think fuel starvation ?.

The weirdest thing I noticed is when it’s regenerating the DPF it’s silky smooth. So strange.

 

[Leighspain1975]

Also looked at VCDS and nothing points to a problem. All parameters are the same when both rough and smooth ?.

 

[B5NUT]

Have you read this thread https://www.audi-sport.net/xf/threads/eliminate-diesel-clatter-cduc-cdud-3-0tdi.381051/#post-3355283

 

[audiA6Q]

Thanks for the replies! One observation is also that when running full thrust in neutral gear it goes up to approx 2400'ish rpm and have somewhat non-silk-run. Haven't tried if there is a different when the engine is in a good mood.. I'll bring it to the shop next week for a check. I'll get back with info from that. Sounds like a good thought in regards to fuel starvation. Will also read through the linked thread!

 

[Leighspain1975]

Hi AudiA6Q

Just wondered if you managed to resolve the problem?.
I still get the problem and have literally tried everything. Don’t know what to do next ?.