My '99 T-reg A6 1.9 TDI (110) has just had its 120,000 mile service, and the dealer suggests I have the air mass meter (amm) replaced because it is sluggish, and replacing the amm will increase power significantly.
It's been sluggish ever since I bought it over a year ago when it was just under 100K miles and the power delivery hasn't changed since then, although I must I've always found it a bit slow, especially when compared to a 1.9TDI (115) I've had for some time. It appears to have quite a big turbo lag (if that's what it is) and often power seems to tail off quite fast when I accelerate and hit about 3,500 rpm.
The question is: is the dealer simply trying to rip me off (for £340) or is this really a problem and should I have the amm replaced? Could I ask the dealer for measurements before and after the replacement which should show an improvement (just in case there is a dispute and I don't notice a difference in power delivery)?
Elsewhere on this site I've read the the amm on a VW 110 TDI (which is effectively the same engine) can fail due to corrosion, but I wouldn't know what the symptoms would be other than reduced power. As I'm not sure how much power my A6 should be giving me, I'm looking for some guidance from you fine folks.
Cheers,
Robert.
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These do sound like the symptoms I see described for a faulty MAF and it does seem to be a common thing for this to fail on the VAG Tdi's. Others have tried cleaning these by hand but I don't know the proper procedure. If you do decide to replace it then I don't believe it's a difficult part to fit so it may be worth sourcing the part from a third party source and fitting yourself.
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They *are* easy to remove and replace - basically some clips and electrical connector. Try EuroCarParts for a cheaper replacement.
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I think you may have trouble sourcing these from anyone other than VAG dealer. In May this year I diagnosed a failing meter on a Passat, went to my local Bosch agent- no stock, try end of June, July, August still none available till end October maybe. Enquired at VW dealer- plenty of stock at warehouse, delivered next day albeit at nearly £100 more than Bosch. I suspect that these sensors are failing so fast that they can only just keep the 'official' sources stocked?
Andrew
Simplicate and add lightness!!
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Local ECP had one on the shelf for a colleague's Passat TDI in mid-July - I don't know the exact details though, I guess there are a number of different P/N's and he may have been lucky.
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You might find some of the answers to my posting re the ongoing Turbo(?) problem on my Audi 80 Tdi helpful.
Good luck
www.honestjohn.co.uk/forum/post/reply.htm?m=168763
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Thanks everyone, this has been really helpful. It seems that there is something wrong with the air mass meter then. Although it seems relatively easy to do it myself, unfortunately I haven't got the time these days anymore to do it myself even though I would have liked to have a go at this.
It's going to the dealer in a few days to get the amm replaced. I will be able to test the performance next week on the German Autobahn :-)
I'll post my findings here later on.
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So the air mass meter has been replaced and I can say that it has made a significant improvement in performance. Almost immediately I noticed more pulling power in the lower revs (the previously described apparent turbo lag has disappeared) and power delivery is smooth through the revs up to the red.
When I brought it in to the dealer to have the amm replaced, I overheard another couple which had the same problem and needed an amm replacement. Coincidence? Hm.
Still feel ripped off for the amount of money they charged me, but very pleased with the result.
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I wonder how many other VAG TDi engines are running around producing only a fraction of the power output they should be.....
--
groups.msn.com/honestjohn - Pictures say a thousand words.....
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