3.0tdi issue

[Snatchrat]

My 09 Audi A4 Allroader has the 3.0 Tdi engine. When driving along the rev counter fluctuates (not by too much I admit) and the car seems to hold back but will accelerate ok when required. The car has been to the local Audi dealer where there were no fault codes and they say that this symptom is normal for this type of engine and automatic gearbox, something to do with the ecu monitoring the torque. Does anyone else with this combination of diesel engine & gearbox have the same issues or am I been fobed off etc. Would an engine re-map help to eliminate this problem. Many thanks.

[SunnyBard]

the car seems to hold back but will accelerate ok when required.

Do you mean it's reluctant from stationary, or any time you accelerate? Always or just sometimes?

[Snatchrat]

Do you mean it's reluctant from stationary, or any time you accelerate? Always or just sometimes?

Hello SunnyBard,
Thank you for replying. Yes the rev counter fluctuates all the time even when accelerating and because of this it feels like the car is holding back. Even in low gears, say holding the speed steady at 20mph the rev needle fluctuates and the car surges a little. Audi say they cant find anything wrong and is the characteristics of this engine but surely this does not seem right. Maybe someone on here with a 3.0 tdi can help or view their comments. Thanks

[dts439]

Is this an S-Tronic or the earlier Torque converter auto?

Its not something I've ever observed with our S-Tronic.

[Snatchrat]

Hi Dave
Yes its the S-Tronic gear box

[SunnyBard]

Yes its the S-Tronic gear box

I've never noticed revs fluctuating (3.0 TDI/S Tronic/quattro)

The one niggle I have with this combo is an occasional "reluctance" to set off sharply, e.g. you see a gap in traffic, you don't need to fully plant the accelerator,but you give it a reasonable poke, instead of obeying orders the car only creeps forward slowly, you give it bit more, still not planting it, and it remains bogged down, not losing grip but just not delivering power to wheels, you're now shouting "COME ON!!" at it, so finally it gets the general idea and sets off how you wished it had originally.

[dts439]

The one niggle I have with this combo is an occasional "reluctance" to set off sharply, e.g. you see a gap in traffic, you don't need to fully plant the accelerator,but you give it a reasonable poke, instead of obeying orders the car only creeps forward slowly, you give it bit more, still not planting it, and it remains bogged down, not losing grip but just not delivering power to wheels, you're now shouting "COME ON!!" at it, so finally it gets the general idea and sets off how you wished it had originally.

Weirdly I find the S-Tronic a lot better in this regard compared to my old (torque converter) B7. In the B7 I used to select sport mode at junctions to get around it (at which point it took off like a scalded cat and hit the car in front). In the B8 I've never bothered to use the Sport mode and seems reasonably alert to throttle inputs.

There used to be problems with VAG cars where recent use of the brake pedal caused the software to mask the next accelerator input, not sure if this still a problem.

Back to the OP question. If its S-Tronic and the revs are fluctuating, is the gear indicator changing as well? Or is it just switching the clutch in and out or clutch slip. Is it only happeneing when you are in one particular gear (or set of gears 2-4-6 , 3-5-7). What sort of rev (actual and fluctuation) are we talking about?

You can try and test for slip by selecting a gear in manual mode (say 3rd) go up a hill and then flooring it. If the revs rise without any corresponding increase in speed then the clutch in that gear train may be at fault. As its DSG I'm guessing that you would also need to do the test with 2nd/4th to test the other clutch.

Finally are all the tyres worn the same ? Can get problems from having newer tyres (with greater rolling radius) on one axle as the car is either continually compressing or stretching itself.

Mines currently at the dealers having both engine mounts replaced (under warranty). They booked it in to do one side, not realising they need to do both sides as a pair, so it staying in for an extra day...

[Snatchrat]

Weirdly I find the S-Tronic a lot better in this regard compared to my old (torque converter) B7. In the B7 I used to select sport mode at junctions to get around it (at which point it took off like a scalded cat and hit the car in front). In the B8 I've never bothered to use the Sport mode and seems reasonably alert to throttle inputs.

There used to be problems with VAG cars where recent use of the brake pedal caused the software to mask the next accelerator input, not sure if this still a problem.

Back to the OP question. If its S-Tronic and the revs are fluctuating, is the gear indicator changing as well? Or is it just switching the clutch in and out or clutch slip. Is it only happeneing when you are in one particular gear (or set of gears 2-4-6 , 3-5-7). What sort of rev (actual and fluctuation) are we talking about?

You can try and test for slip by selecting a gear in manual mode (say 3rd) go up a hill and then flooring it. If the revs rise without any corresponding increase in speed then the clutch in that gear train may be at fault. As its DSG I'm guessing that you would also need to do the test with 2nd/4th to test the other clutch.

Finally are all the tyres worn the same ? Can get problems from having newer tyres (with greater rolling radius) on one axle as the car is either continually compressing or stretching itself.

Mines currently at the dealers having both engine mounts replaced (under warranty). They booked it in to do one side, not realising they need to do both sides as a pair, so it staying in for an extra day...

Hi DTS439

I will test the clutch theory out on the way home tonight. Interestingly I have noticed that the front tyres are mitchelin and the rears are dunlops. All tyres are the same size but I wouldn't have thought that different makes would cause this issue, there again I could be wrong! I have recently purchased this car so I am still learning its characteristics after coming from a S6 Avant.

[dts439]

Its not so much the makes being different as the how worn they are (and consequent rolling radius differences), i.e.new tyres on front (8mm tread) and worn (3mm tread) on the back.

I was annoyed to find the front tyres on mine were different to the back (and I'd bought it used from Audi). If the tread patterns are widely different (e.g. Assymetric and not) then it can't be good thing, but don't think it would cause your symptoms.

I think you need to give more exact details of the fault/symptoms for us to compare against, but you say on a constant throttle at 20mph the car surges / revs hunt ?

[Snatchrat]

Its not so much the makes being different as the how worn they are (and consequent rolling radius differences), i.e.new tyres on front (8mm tread) and worn (3mm tread) on the back.

I was annoyed to find the front tyres on mine were different to the back (and I'd bought it used from Audi). If the tread patterns are widely different (e.g. Assymetric and not) then it can't be good thing, but don't think it would cause your symptoms.

I think you need to give more exact details of the fault/symptoms for us to compare against, but you say on a constant throttle at 20mph the car surges / revs hunt ?

Hi Dave

Yes the car surges and the revs hunt approx 100 to 200rpm in all gears even when traveling at a constant speed, though when traveling at motorway speed the symptoms seem to be a lot less noticeable.(car doesn't lose speed when accelerating up hills so don't think it is gearbox issue).

This morning because it was so cold it was more pronounced and not enjoyable to drive. Could this be a problem with the MAF? I remember when I had my S6 (sorely missed) there was a problem with the MAF which didn't show up on any of the diagnostic scans and was only the experience of the mechanic who diagnosed this. Once changed car was back to normal.

Audi have said that they know that there is an issue with this engine/gearbox combination and at the moment there isn't a update to solve this problem. Only thing is that I don't really believe them as surely this is not normal behavior for a car.

My wife's two litre diesel VW doesn't have any of these issues and is a pleasure to drive with the DSG gearbox.

Anybody have any suggestions or experience these issues with their 3 litre diesel and s-tronic gearbox? Many thanks in advance.

[dts439]

Will try mine out when I get it back. If you have cruise, what does the car do when you select it - still surge/hunt?


i thought the whole point of a DSG gearbox was the lack of a torque converter so you were always in one gear and got the economy benefits of a manual. Only downside over a normal auto in that it needs to slip the clutch when pulling away or crawling in traffic/parking.

[Snatchrat]

Will try mine out when I get it back. If you have cruise, what does the car do when you select it - still surge/hunt?


i thought the whole point of a DSG gearbox was the lack of a torque converter so you were always in one gear and got the economy benefits of a manual. Only downside over a normal auto in that it needs to slip the clutch when pulling away or crawling in traffic/parking.

Hi Dave

Once again many thanks for your quick reply. I will try the cruise control as you suggested to see if that makes any difference. In your own car I am sure you would notice the same symptoms!

[dts439]

Got my car back and went on a reasonably long journey. At no time did I see a waivering of the rev counter at constant speed. You can see it slightly bounce as it changes gear, but thats about it. I tried a constant 30mph and it was fine, putting itself in 4th gear.

[Snatchrat]

Got my car back and went on a reasonably long journey. At no time did I see a waivering of the rev counter at constant speed. You can see it slightly bounce as it changes gear, but thats about it. I tried a constant 30mph and it was fine, putting itself in 4th gear.

Hello dts439

Many thanks for taking the time for taking your car out for a run and reporting back on your findings. This weekend i had a look at the air filter and to my surprise it was minging, bits of leaves and other debris clogging up the filter.

According to the Audi garage the car was supposed to have been serviced before I took collection! So I am now going to book it into my local friendly Audi independent specialist for them to give it the once over to see what they find as I don't believe that my car should behaving as it is. Also just like your car, the rev counter will slightly bounce as it changes gear which of cause is normal but mine will also waiver as i travel along in all gears and at constant speed. I will let you know on what the garage manage to find.

[Snatchrat]

Hello dts439

Many thanks for taking the time for taking your car out for a run and reporting back on your findings. This weekend i had a look at the air filter and to my surprise it was minging, bits of leaves and other debris clogging up the filter.

According to the Audi garage the car was supposed to have been serviced before I took collection! So I am now going to book it into my local friendly Audi independent specialist for them to give it the once over to see what they find as I don't believe that my car should behaving as it is. Also just like your car, the rev counter will slightly bounce as it changes gear which of cause is normal but mine will also waiver as i travel along in all gears and at constant speed. I will let you know on what the garage manage to find.

For those that are interested, - finally got to the bottom of the issue with my car. Changed air filter has it looked like it was the original and had been in there for the last 30k miles. Also replaced MAF as I expected bits of chud had got past filter and contaminated MAF. The results are that the car is performing and behaving as it should and really flies now. Really pi55ed off at Audi Tonbridge from where I purchased the car (was supposed to have been serviced before delivery), and also Audi Southampton for not diagnosing the problem properly and fobbing me off saying that this was normal for a 3.0 Tdi:aargh4: Think I am going to write a letter of complaint to Audi Customer Services to let them know of my experience of their used car programme etc. Might even ask for the £250 that its cost me to put the car right. Sorry rant over but had to get it off my chest.

[dts439]

Glad to hear its all sorted out. Does sound like you had been fobbed off.