Paullorman Posted January 30, 2005 Report Share Posted January 30, 2005 Hi all, After my recent purchase of VAG-COM I think my MAF may be faulty. I bought VAG-COM to see if I could see why my idle is slightly lumpy, both when cold and warm. Having a 2001 A6 4.2 V8, I would have thought it would be smooth as silk but when idling at ~600rpm, you can feel a slight shudder. Upon connection I find the following codes VAG-COM Version: Release 409.1-S Control Module Part Number: 4D0 907 560 H Component and/or Version: 4.2L V8/5V G 0001 Software Coding: 05752 Work Shop Code: WSC 02325 2 Faults Found: 17536 - Fuel Trim: Bank 1 (Mult): System too Lean P1128 - 35-00 - - 17538 - Fuel Trim: Bank 2 (Mult): System too Lean P1130 - 35-10 - - - Intermittent Reading the excellent tech article on fuel trim by andy@Ross-tech, Fuel Trim I looked at the fuel trim settings. These are as follows:- -2.4% 22.7% -2.4% 21.1% I have also performed a second gear full-throttle run to measure the air mass. The maximum figure I achieved was 159 g/s As I am supposed to have 300bhp, I believe the top figure should be around 240 g/s. Could someone with greater knowledge than I confirm that it appears my MAF is faulty? I have been given a price for a new MAF of £210 ($375) however, the car is still under Audi warranty! Has anyone got any ideas how I can get Audi to pay for this? I am not sure how I can convince Audi my car has fault codes! Thanks in advance! Paul Link to comment Share on other sites More sharing options...
Tomk Posted January 30, 2005 Report Share Posted January 30, 2005 just pop in the dealer say you have linked up your car and its giving fault codes ! you have not validated your warrenty by checking if your car is ill - though i may be wrong ! what do people think ? Link to comment Share on other sites More sharing options...
Botang Posted February 1, 2005 Report Share Posted February 1, 2005 Tom MAF's dont generally bring up dault codes, which is why you have to compare the figures. The MAF is constantly measuring air flow across a range so as long as the figures are within that range it'll think its ok, so it cant recognise that its wrong until its very bad. I hope you understand what I mean. Link to comment Share on other sites More sharing options...
Botang Posted February 1, 2005 Report Share Posted February 1, 2005 Paul from the figure you have quoted it does indeed seem that your MAF is faulty, the only real way around it is to replace it. Audi should cover it under the warranty, and I have known of them doing it under warranty on other cars so they should know what you are on about. I would quote the figures that you have measured to them, all the dealers would know what VAG-com is and in my opinion would not try and fob you off as you know what you are on about. Just checking you do have the standard air filter dont you? Link to comment Share on other sites More sharing options...
Ben Posted February 1, 2005 Report Share Posted February 1, 2005 Just disconnect it and run the car. The engine will take its readings from other engine sensors, then reconnect. This may well throw up a MAF relted code that the dealer can see and will compound the theory that it's knackerd. This certainly works with late S3's. Cheers Ben Link to comment Share on other sites More sharing options...
Paullorman Posted February 1, 2005 Author Report Share Posted February 1, 2005 Yes airfilter and car all completely standard. Thanks guys for your help, I'll see how I get on! Paul Link to comment Share on other sites More sharing options...
Mollox Posted February 14, 2005 Report Share Posted February 14, 2005 I've been wondering whether my MAF has gone west. Performance seems to vary a bit, there's occasional hesitation and, although it may just be my imagination, the engine note seems a little gruffer. Finally got round to opening the bonnet and unclipping the MAF lead last night. Took it for a short run and wasn't quite sure. There seemed to be more consistent boost, the car seemed a bit keener and sounded a little 'zingier' (less gruff to you and me!). Although i might just have been wanting to feel that. It really is hard to tell. Tried it with the MAF back on and it was a bit jerky coming off the throttle which was a little odd. Didn't really have more than 3 mins to try it with the MAF again so will do a longer run including motorway on...oooh its Valentine's tonight, wednesday I suppose. And we will see... Link to comment Share on other sites More sharing options...
Paul Posted February 14, 2005 Report Share Posted February 14, 2005 Mollox you can always log it with vag-com. a quick blast up the road, will log its peak Grams/sec a breathed on S3 should be getting around the 190+ g/sec at peak rpm Ive used it to check mine in the past. tho i am not so confident with the boost actual vs requested Link to comment Share on other sites More sharing options...
Mollox Posted February 15, 2005 Report Share Posted February 15, 2005 Popped out for a minute earlier. Strange things happened. The car was very cold and moving out of my space the engine was making a wheezing sound each time I went to move and then the revs would surge to 1800 rpm then drop. Idle was around 1200 too which was wrong. It was doing it repeatedly so I stopped, checked the connection on the MAF, a bird shat on the roof, I was angrier, and then tried again. Same thing so I thought I'd drive it gently and let it warm up. Once warm it didn't do it. I'll have to check it again from cold tomorrow. Odd - its never not idled properly in 4 years and then this.... Link to comment Share on other sites More sharing options...
Mollox Posted February 17, 2005 Report Share Posted February 17, 2005 Phew, seems fine again (i'd do a smiley but they're broken). Seemed faster again tonight. Think I'm going to pop on a new MAF as a precaution. Might wait for Sunday to datalog MAF values but then again I might just get it done before so I can be right for the RR day. Decisions. This little episode has reminded me how just much of an effect a MAF has on a turbo'd car... Link to comment Share on other sites More sharing options...
Paullorman Posted February 20, 2005 Author Report Share Posted February 20, 2005 Just to let you know... my new MAF FINALLY arrived; £213 from VAG. Changed it in 10 mins (would have been 5 if Audi had not been daft enough to put the two bolts that hold it on at 12 and 6'O Clock position). Went for a spin, no fault codes, fuel trim perfect, correct breathing 243g/sec. Problem solved :-D Link to comment Share on other sites More sharing options...
steve2 Posted February 22, 2005 Report Share Posted February 22, 2005 just had my MAF replaced under extended warranty today and she is a completly different car now, big grins on face, Link to comment Share on other sites More sharing options...
Recommended Posts
Please sign in to comment
You will be able to leave a comment after signing in
Sign In Now