A6 2.5Tdi Quattro sport MAF

[charlie_kerr]

Any help appreciated, my A6 is a bit hesitant at low revs, and I was thinking of changing the MAF to try and see if there was a difference, three questions:

I have a registered copy of VAGCOM but don't know how do much more than run simple error checks, is there a specific test that can validate the MAF performance ?

I have a brand new MAF Bosch part 0281 002 429, but I notice the actual model for this car is 0281 002 430, but on the Marelli website they offer a single unit as a replacement for both Bosch No's, is there a difference which would be significant.

I have the tiptronic g/box, not the multitronic, 60k miles, is there a known problem with high revs at low speed (approx 2k rpm before changing 1st and 2nd), or is this natural?

And crap MPG

Cheers guys.

 

[fjtwelve]

Is this a new problem? If you are new to the car, be aware the 2.5TDIs are all slow off the mark until about 1800rpm. My Turbochip improved this but didn't eliminate it. MAF problems tend to manifest themselves higher up the rev range.

1 Ask this question on the VAGCOM forum, you should get a better response. Simplest test there is - unplug the MAF go for a drive if there's no change its knackered.
2 Although covered in VAG 4 ring logos my MAF is actually Hitachi 059 AFH 70 250 so can't help you there i'm afraid. Any decent Audi independent eg Star Performance will advise on what will fit.
3 Sorry have a manual

Crap mpg yes could also be pointing at MAF but you do have an auto. My manual quattro averages 33 overall, 31 round Cornwall lanes and windy roads. What are you getting?

 

[charlie_kerr]

Thanks fjtwelve, I've had the car since November, previously had a 1.9tdi manual, and notice the slow respons in low gears through the auto box, and trying to see if theres a solution. Sounds like it is normal, I'll try fitting the spare MAF and see if it makes a difference. MPG is around 28, but as you say the auto box combined with the 4WD, and a heavy foot probably explains.

Thank for the reply.

 

[SiliconS]

Hi Charlie,

The tiptronic 'box senses your driving style and adapts its gearchange points accordingly. If you're driving for economy at low throttle then it will change up early (which is normally how I *try* to drive).

Occasionally, though, I need to accelerate hard away from a standstill and if I do this the 'box changes its mode significantly, holding onto gears much longer to give me the performance that my heavy right foot has just demanded, even for a couple of minutes after I've reached cruising speed again.

If your gearbox is holding onto gears longer than you'd expect then it may be that you're sending it inputs that make it think you're seeking performance. Perhaps you're jabbing the throttle to accelerate instead of smoothly pressing it. (I don't know what inputs trigger the behaviour.)

When the engine is cold, the 'box will hold onto gears for longer too, to allow the engine to warm up at higher revs but lower combustion loads.

I came from an auto Mercedes E-Class to this Audi and I was stunned by how much more sophisticated the Audi 'box seems to be by comparison.

Hope that helps,
Ben

 

[charlie_kerr]

Thanks Ben,

Your are right the amount of foot used has adirect effect on the gear change. Re some of the responses and my experience it would appear that the 2.5 V6 is a bit 'flat' in lower revs. It's very frustating to turn a corner, hit the pedal and wait a few secs till the revs catch up, not like a manual where you can control the revs a bit better, maybe a re-map will help.


Thanks for the response, it all adds up to a better understanding that there is nothing wrong with the car.

Just turned 60k, but Audi Glasgow have contacted me with a recommendation to change the timing belts because the car is now 5 years old, quoted £385, which I'm told is not too bad.

Cheers
CK