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| D2 - Fuel and Exhausts Everything to do with getting fuel into the engine, and fumes back out again |
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#1
16th May 2011, 11:57 AM
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Not the Cat curse again - surely?
The list gets longer!
 2 cats on my old A8, 2 new 'sports' cats on my S8, a new cat on my daughter's 206 just after we picked it up and, after standing close to briang9's S8 at the Scotland mini-meet, his cat went too! Then my engine management light came on again, so I swung by A4 Audi on the way home last week and the VagCom said both cats were out of tolerance. But the light went off the following day and has stayed off for a couple of hundred miles or so. The new cats are only around 7 months old and under guarantee, but is it likely to be them or maybe just a bit of gubbins in the petrol (BP Ultimate, always)? Any thoughts guys? BTW - I'll stand well away from your '8 at June's meet for a small fee! 
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#2
16th May 2011, 10:20 PM
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Which lambdas where showing the fault. If it's the one after the CATS then it will probably be because you have sports cats.
__________________
Conan (the Librarian) Watch it if you dare Currently, 2000 S8, Merlin Purple, Leather Pack 1, Winter Pack 1, SPAX adjustable suspension, AP Racing 6 pot front caliper, 385mm fully floating disks, EBC Yellow Stuff Pads, Black Diamond grooved rear disks and predetor pads, D2 Doctors Brake Block. 1997 4.2 A8SQ - the Projekt. 12 years and ongoing! 1997 4.2 A8SQ - Ming Blue. Restoration sat waiting; saved from the Scrapyard 2003 C5 Allroad 4.2Q - Cobolt Blue. Towing car. Laid up awaiting manual conversion. 2005 C5 Allroad 2.5TDi FE - Grey - Workhorse. 2015 Q3QS SLine - Daytona Grey. Lots of extras! Long Haired Admirals cutter. Previously 2003 C5 A6 1.9TDI FWD - Loaner from D2 Doctor Lifex 1997 S8 - Ming Blue. Loaned out and written off. I loved that car. My first engine swap after cambelt failure. 1996 4.2 A8SQ - Ming Blue. 178k on a cambelt! Trader's 8. Delivered to A8Parts at Lifex. 2003 2.8 A8SQ - powder blueish. Fill in for a while. Sold on. 1998 1.8T A4 Avant FWD. Ming Blue (there's a theme here), PEX for the 97 S8. And a list of non VAG going back 40 years before I saw the light. 
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#4
17th May 2011, 06:03 AM
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You have a FL S8 Jim, with Lambdas before and after the cats. The ones after the cats monitor the efficiency of the cats. With the sports cats there are generally only 100 or 200 CPI whereas in the standard cat there is 400 CPI. The more CPI the better the cats clean up the exhaust gasses. The less CPIs the better the car performance. The post cat Lambdas are probably registering the exhaust gasses out of programmed range occasionally and throwing a fault. There is a modification that can be made to the lambda housing that eradicates this problem.
Here is a thread on the subject. This thread discusses the technique to alter AFR; but it is the same for post cat lambdas to stop faults.
__________________
Conan (the Librarian) Watch it if you dare Currently, 2000 S8, Merlin Purple, Leather Pack 1, Winter Pack 1, SPAX adjustable suspension, AP Racing 6 pot front caliper, 385mm fully floating disks, EBC Yellow Stuff Pads, Black Diamond grooved rear disks and predetor pads, D2 Doctors Brake Block. 1997 4.2 A8SQ - the Projekt. 12 years and ongoing! 1997 4.2 A8SQ - Ming Blue. Restoration sat waiting; saved from the Scrapyard 2003 C5 Allroad 4.2Q - Cobolt Blue. Towing car. Laid up awaiting manual conversion. 2005 C5 Allroad 2.5TDi FE - Grey - Workhorse. 2015 Q3QS SLine - Daytona Grey. Lots of extras! Long Haired Admirals cutter. Previously 2003 C5 A6 1.9TDI FWD - Loaner from D2 Doctor Lifex 1997 S8 - Ming Blue. Loaned out and written off. I loved that car. My first engine swap after cambelt failure. 1996 4.2 A8SQ - Ming Blue. 178k on a cambelt! Trader's 8. Delivered to A8Parts at Lifex. 2003 2.8 A8SQ - powder blueish. Fill in for a while. Sold on. 1998 1.8T A4 Avant FWD. Ming Blue (there's a theme here), PEX for the 97 S8. And a list of non VAG going back 40 years before I saw the light.
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#6
17th May 2011, 10:13 AM
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na na na na CAT MAAAAANNNNNN!!!
__________________
Confidence is the feeling you have before you know better . . . .  Audi A8 D2 3.7 Quattro Sport 1999 FL - Melange 2nd Place Winner - A8-Freunde Annual German Meet 2012 at Edersee 20" x 9" Bentley GTC Wheels with 385mm W12 Front Discs & Bentley Caliper Covers, Front Lowered on Coilovers, Xenons, Combined DRLs and LED Foglights to modified OEM front fog lamp position, Alcantara/Leather, Full Black Alcantara headlining + pillars and blind shelf, Bespoke Flat Bottomed Sports Steering Wheel, Dark Myrtle Wood, Autodim Mirrors, Bose, Blinds, Digital TV, Ski Hatch, Modified rear exhaust section for extra V8 Burble  Audi S8 D2 Final Edition 2002, Avus Silver with Red Leather Interior Tiptronic with Sport mode button, Sony rear entertainment package, Bose sound system, Audi Navigation Plus, 20 inch Final Edition alloys, Full Cat Back Stainless Milltek exhaust, giving a great V8 burble Audi A8L D2 4.2 Petrol with LPG - Ebony Black Audi A8L D4 FL 4.0T Petrol twin turbo - Havana Black Audi A2 1.6 FSi Sport - Dolphin Grey with Votex body kit and Red Leather Interior and some other A8's A8L's and Mercs
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#7
17th May 2011, 10:25 AM
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Out of interest how much are a pair of cats for a 4.2 V8? Might aswell know what I'm getting myself into!
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#8
17th May 2011, 10:58 AM
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Got mine done last week, around the £500 for two sports cats, I did contact an Indie in the Area and they wanted around £1200 to fit only one of the Genuine Audi ones
__________________
 Audi S8 2002, Black (even the chrome bits) Audi RS6 Avant 2008, Daytona Grey Maserati Granturismo 2008, Metallic Nero Carbonio Audi S8 2015, Daytona Grey
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#9
18th May 2011, 08:51 PM
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I 've spoken to Semtech and they're more than happy to take the car in and honour the guarantee. The sports cats are 200 cpi, apparently, compared to 400 dpi standard. Stevie said they only fit 100 dpi to track cars.
But, anyway, the light went off after around 24 hours and hasn't come back on in a few hundred miles. So I'm hoping for a glitch from a bit of gubbins. BTW - can I change my user name to 'Catman' and keep my 'senior member' status?
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#10
18th May 2011, 09:50 PM
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Quote:
__________________
Confidence is the feeling you have before you know better . . . . Audi A8 D2 3.7 Quattro Sport 1999 FL - Melange 2nd Place Winner - A8-Freunde Annual German Meet 2012 at Edersee 20" x 9" Bentley GTC Wheels with 385mm W12 Front Discs & Bentley Caliper Covers, Front Lowered on Coilovers, Xenons, Combined DRLs and LED Foglights to modified OEM front fog lamp position, Alcantara/Leather, Full Black Alcantara headlining + pillars and blind shelf, Bespoke Flat Bottomed Sports Steering Wheel, Dark Myrtle Wood, Autodim Mirrors, Bose, Blinds, Digital TV, Ski Hatch, Modified rear exhaust section for extra V8 Burble Audi S8 D2 Final Edition 2002, Avus Silver with Red Leather Interior Tiptronic with Sport mode button, Sony rear entertainment package, Bose sound system, Audi Navigation Plus, 20 inch Final Edition alloys, Full Cat Back Stainless Milltek exhaust, giving a great V8 burble Audi A8L D2 4.2 Petrol with LPG - Ebony Black Audi A8L D4 FL 4.0T Petrol twin turbo - Havana Black Audi A2 1.6 FSi Sport - Dolphin Grey with Votex body kit and Red Leather Interior and some other A8's A8L's and Mercs
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