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Hi all just wanted to thanks. Have resonantly become the proud owner of a 2007 RS4 black,67000miles miltek did have decat pipes fitted but removed them. Just to loud for the neighbours. 20" Niche wheels, full KW coilovers. Spent the last 3 months of ownership getting the car just so. I have also just carried out a carbon clean my self. Thanks to everyone on here. Got all the info I needed from you guys.
I just have one question. After all the work I have done I have a CEL. Codes are P2097 and P2098 bank 1 to lean and bank 2 to rich. Leading to one of three things vacuum leak, MAF sensor, or lambda probes. I have changed the MAF and don't have a vacuum leak. This leaves the lambda probes, but how do you know which one has failed? CEL comes back on after about 60 miles. Very annoying!

Can't help with your problem but FON and welcome!

Nice upside RS4, in the best colour! Not a big fan of those wheels though.

They sure like an audi in your neighbourhood don't they?

T5svw wrote:did have decat pipes fitted but removed them

Hello fella - welcome to the club and FON - a friendly observation ....

I am perplexed as to what you mean by removing the decat pipes, out the factory the RS4 has 400cel cats in the down pipes these are known as the pre cats - there is no silencing at this stage. After the down pipes comes 200cel 'sport cats' and these form part of the 'cat back exhaust' - All the silencing is done at this stage. The reason most of us gut the precats (or remove them) is that there is power to be gained. There maybe a little silencing going on due to pulse restriction but I would have thought that it does not make that much of a difference. You would be far better off leaving the down pipes free of cats and run the miltek perhaps with additional silencing (I imagine you have a non res without valves) which you should be able to get any decent exhaust fabricator to do for you. If you leave the down pipes without the cats and go for a decent stage 2 by someone like MRC

Hi there and welcome

The layout of the O2 sensors are as follows;

Bank (1) cylinders 1 - 4 - bank 1 sensor 1 is the pre cat sensor on the drivers side and bank (1) sensor 2 is the post cat sensor on the drivers side

Bank (2) cylinders 5 - 8 - bank 2 sensor 1 is the pre cat sensor on the passenger side and bank (2) sensor 2 is the post cat on the passenger side

I have used the Ross tech VCD's to identify a faulty O2 sensor on mine

The car already had the Miltek fitted complete with decat down pipes. Did not run well with decats either. I would say it had not been coded for the decats. The second lambda on both sides were simply turned off!! I will get the car up to MRC at some point. Just want CEL off for the time being.
Mike fish sorry to hear your not keen on the wheels. May be this pic helps shows the concave off

sync24 wrote:

T5svw wrote:did have decat pipes fitted but removed them

Hello fella - welcome to the club and FON - a friendly observation ....

I am perplexed as to what you mean by removing the decat pipes, out the factory the RS4 has 400cel cats in the down pipes these are known as the pre cats - there is no silencing at this stage. After the down pipes comes 200cel 'sport cats' and these form part of the 'cat back exhaust' - All the silencing is done at this stage. The reason most of us gut the precats (or remove them) is that there is power to be gained. There maybe a little silencing going on due to pulse restriction but I would have thought that it does not make that much of a difference. You would be far better off leaving the down pipes free of cats and run the miltek perhaps with additional silencing (I imagine you have a non res without valves) which you should be able to get any decent exhaust fabricator to do for you. If you leave the down pipes without the cats and go for a decent stage 2 by someone like MRC

Kev, I get why he did it. A full blown Milltek with no cats is pretty bloody loud. Replacing the cats will take some of the edge away and at the same time take the headache away of having to swap out the downpipes or get a dodgy MOT every year.
Agreed he would be getting more power by leaving the decats in and silencing the cat back but for me the MOT hassle is not worthwhile.

T5svw wrote: Mike fish sorry to hear your not keen on the wheels. May be this pic helps shows the concave off

image.jpg

The concave on the front wheels looks nice and I love dark coloured wheels but still not a fan of the style. I've seen others in here rave about similar wheels so I guess it's just me.

Do you have spacers on those wheels or have they got a low offset (or maybe they are crazy wide)? That front wheel is sticking out quite a bit! Do you find the wheels rub at all?

Wheels are 20x10 so very wide 12mm spacers all round. The only time it rubs is with 4 adults in the car. I have spent a lot of time getting the camber set up correctly. Luckily I have a mate in the tyre trade his company has the hunter alignment system. Thinking of changing the colour of the wheels. Maybe they will look better After that. Got the car with all the mods I just have sorted them out. First time owning an Audi always had vw golfs, MK 1 mainly. Used to fit 16v tall blocks in. They when like go carts. Now have T5 van and the RS.

T5svw wrote:The car already had the Miltek fitted complete with decat down pipes. Did not run well with decats either. I would say it had not been coded for the decats. The second lambda on both sides were simply turned off!! I will get the car up to MRC at some point. Just want CEL off for the time being.
Mike fish sorry to hear your not keen on the wheels. May be this pic helps shows the concave off

image.jpg

Hi and welcome

You say that you have replaced the decat pipes, what with ? Have you put the pre cats back in ? Have you fitted sports cats ?
If you have fitted sports cats / standard cats and eliminated the pre cats then you need to space out the 2 lambda sensors, I don't know by how much but there are a couple of threads on here relating to that, and also spin the cats 180* so that the lambda sensors are at the back, this eliminates any error codes.
Has the car been mapped ? If so by who ?

The 400 cell pre-cats and the 200 cell main cats are both located in the downpipes, yes?

coffey555 wrote:The 400 cell pre-cats and the 200 cell main cats are both located in the downpipes, yes?

Correct.

Yes both 400 cell and 200 cell cats are located in the downpipes.
NJM. I have fitted the standard downpipes with both cats still in place. When I put the standard downpipes back on I put all the lambda sensors back where they were in the decat pipes. Now you mention about swooping them round maybe that's why I keep getting CEL back. Now I just need to find out Which way they actually go!

Cheers, I was pretty sure the main cats were not located on the cat back part.

Have you noticed much difference in noise with the standard downpipes back on? I would expect it to be a good bit quieter with less rasp?

Massive difference, very little boom inside car now, but still sounds nice.