Just became an RS6 owner - a few questions on stage 0

[IRS6I]

Hello all,

I bought a dark gray RS6 Avant (light brown interior) a few days ago here in Moscow (RU). I'm actually Belgian but live in Russia most of the time for my work. The RS6 seemed like a good choice for the winters they have here. I'm no stranger to cars or modding them, I have a 420bhp volvo 850 T-5R track car that I drive on the Nurburgring regularly. The RS6 was imported into Russia from Germany in 2007, which is nice for me because unlike Russian I can actually understand German.

Anyhoo, before buying I had it checked over at an official audi dealer, they didn't find too much, there were some error codes in the ECU related to the catalytic convertors (or so my girlfriend managed to translate for me) that they said could possibly be related to tired oxygen sensors. There was a slight oil leak from the PS system where it attaches to the cooler (?) and they recommended spark plug, air filter changes and injector cleaning.

I had the oil and filter changed together with the plugs and air filters. They asked a small fortune for injector cleaning and couldn't give me a good explanation why they felt it was necessary. So I decided to see how the car feels first and maybe get them cleaned myself.

The car runs well, taking into account the weight and quattro I think most of the 450 horses are there. The only odd thing in how it runs that I've discovered, is that while idling in N or P it is slightly irregular with a bit of a vibration going through the whole car. Put it in D and it smooths out completely to what I would guess has to be "normal". Accelerating slow, medium or fast the engine is smooth at all revs. Only idle in P or N is strange.

Also earlier during idling in a traffic jam (where I've spent most of my time so far) the CEL came on. I've ordered a cable to be able to run vagcom but I haven't got it yet so can't read the code. I'm guessing it'll be a fuel or emissions related code. I did have to put in some possibly poor fuel the day before because I wasn't confident I could make it to the BP station near my home. I put in half a tank (way too much looking back) of some russian 95 ron of unknown quality, then filled it up for the rest with BP 98 ron "ultimate" which is the biggest brand fuel I can find here.
So I'm not sure if it's complaining about the fuel but it does still run normal and power seems unaffected. My past experience with turbo cars would guess a small vac leak is possible too but I won't presume on that with this thing.

I guess I'm looking at swapping to new MAFs and O2 sensors for a start? Should I only do the pre-cat widebands for a start or all 4 of them? Anything else?

Also while I'm at it, every time I start the car I get a message about the emergency phone dialing being restricted and a large "OK" button. I can turn off the phone in the centre arm rest and then go into the onboard computer menu but I can't for the life of me figure out which button I'd have to press for the "OK" ? (have got an english operation manual on order) slightly annoying. (I have the 3 spoke steering)

Last thing, is it normal that at full lock (or high amounts of steering lock in general) there is a slight shudder in the front of the car almost like a tire rubbing (but it isn't) almost feels like the diff working in some way.

Currently I don't really plan on chipping the car, I'm a little worried how the gearbox would take it. I'll probably get the box serviced too (how much should they be asking me for that?)
If the cats turn out to be junk I'll happily put on catless DP's since the technical inspection around here is easily avoided with a couple hundred $ for the certificate. Of course I imagine I'd have to get a tuner to delete the rear O2's for me.

TIA, I'll post up some decent pics when I make them.

JC

Depnding onthe year it was built the trans may have the upgraded torque converter seal meaning it will handle a chip no problems mine handles more power than the chip and lots of drump and 400m runs.

[Shoppinit]

Please don't quote whole messages unnecessarily

[JCviggen]

I got an OBDII cable and while waiting for Ross-tech to ship my license key I checked what DTCs currently exist:




P0441 EVAP emission control sys: Incorrect Flow - Lower Limit Exceeded - Intermittent

P3012 Fuel pump relay - open circuit/short to earth - Intermittent

P1065 Fuel pressure - system deviation - Intermittent

P1455 EGT sensor 1 : Implausible signal - Intermittent

P1127 Long term fuel trim Mult.- bank1 too rich - Intermittent

P1138 Long term fuel trim Add. - bank2 too lean - Intermittent

P1129 Long term fuel trim Mult.- bank2 too rich - Intermittent


The fuel pump and -pressure related codes I'm pretty sure that's because there is an aftermarket immobilizer installed that cuts the fuel pump and i've accidentally triggered it a few times by not taking care to swipe the credential near where the receiver is implanted.

A little confused about getting both too lean and too rich message on bank 2 though.

Any ideas where I should start troubleshooting? Vac leak or sensor issue(s) ? A vac leak I'd expect lean rather than rich..

I can believe the "rich" part because it does use a bit more fuel than I was expecting (I was expecting a LOT) cruising at 60-70mph on the highway its usually displaying around 20 MPG (which is a tad more optimistic still than the truth) which is more than it should be at a steady cruising speed and low revs.

[Shoppinit]

Any ideas where I should start troubleshooting? Vac leak or sensor issue(s) ? A vac leak I'd expect lean rather than rich..

I can believe the "rich" part because it does use a bit more fuel than I was expecting (I was expecting a LOT) cruising at 60-70mph on the highway its usually displaying around 20 MPG

If you've got a boost leak (intercoolers) you'll suck unmetered air in off boost (negative pressure) and blow out metered air under boost (positive pressure) so this doesn't surprise me.

Start off by clearing all the DTCs and seeing what comes back. Some of them may be old.

[JCviggen]

Cheers, what's the difference between Add and Mult for the fuel trim? I'm new to VAG ECU's sadly

I could imagine there being a difference in codes between full throttle enrichment and just cruising at lambda 1 ?

I'll clear them but in all likelyhood they haven't been in there for very long. The CEL came on after a few days so they were probably cleared by the seller.

[JCviggen]

After 30 miles (and 2 hours of mostly idling due to traffic jams) the codes are back (and the CEL)

6 Faults Found:
17535 - Fuel Trim; Bank 1 (Mult): System too Rich
P1127 - 002 - Lower Limit Exceeded - Intermittent
17537 - Fuel Trim; Bank 2 (Mult): System too Rich
P1129 - 002 - Lower Limit Exceeded - Intermittent
17546 - Fuel Trim: Bank 2 (Add): System too Lean
P1138 - 001 - Upper Limit Exceeded - Intermittent
17544 - Fuel Trim: Bank 1 (Add): System too Lean
P1136 - 001 - Upper Limit Exceeded - Intermittent
17861 - Exhaust Gas Temp Sensor 1 (G235): Open or Short to Plus
P1453 - 001 - Upper Limit Exceeded - Intermittent
16825 - EVAP Emission Control Sys: Incorrect Flow
P0441 - 002 - Lower Limit Exceeded

So pretty much all of them :rolleyes:

Can all these be traced back to a single problem you think? (fuel trims are obviously related but EGT and EVAP ?)

[RS6Steve]

Look at the front of your intercoolers are there any oily marks across the corners?

Probably best to get a pressure test done me thinks.

I think EVAP is related to the Secondary Air Pump?

[JCviggen]

How visible would this be from the top? I had the bonnet open earlier and looking from the top they looked all right but you really can't see all that much. The hoses looked a little tired however which is to be expected after 6 years.

Annoying to be stuck with no tools, will try to get it to a garage and hunt for leak(s). I don't remember it idling a little rough when I inspected it, they replaced plugs (OEM) and air filters and now it does. The filter covers looked to be on snug though.

How do I get to the MAF readings in VCDS? I believe the info is in a specific address?

[JCviggen]

OK, played around a bit more

Could only see 1 corner of the IC's properly but both of them are a little darker/greasier than normal in those corners. Not exactly wet but definitely a tad greasy.



Idle MAF readings around 3.5~3.8 g/s on both (so 7 and a bit total) around 10.5 each at 2500.

Vid of vcds http://www.greenringer.net/various/vcds.3gp

[Shoppinit]

Yes, that's a leaking intercooler.

Idle readings sound about right. Use advanced measuring blocks and log a drive. Put the data in excel and let's have a look. Looking for something like this:

[JCviggen]

OK I tried that, didn't find advance measuring blocks but logging it in standard mode worked OK.

Idle air flow readings I mentioned earlier are wrong, btw. They are 3.5-3.8 when the engine is cold...when warmed up it is 3.5-3.8 per channel in "D" but if I put it in N or P when its warm it drops to 2.5 g/s which I think is too low (vac leak)?

I haven't got time to put it in a nice graph, but here is the raw data. Actually the logging only seemed to work when full throttle, I've removed the other data because it was useless, all numbers in the 36xxx-40xxx range can't make sense of it. Example see the timing advance column.

The time jump between each line is quite big, this was 3 pulls in total. Adding up the airflow it seems to flow around 360 g/s maximum around 6K rpm (/ .8 would be exactly 450) so the boost leak itself is probably rather small, I would expect to see more flow if I was overspinning the turbos and wasting air...

[Shoppinit]

What version of VCDS are you using? Looks like a software glitch to me, rather than data from the car.

[Shoppinit]

I think you have multiple problems. The most worrying one is the EGT. The engine is supposed to come out to change these, but I have heard that it is possible to change them in-situ.

The EVAP is the active charcoal filter system. Probably the filter needs changing. I don't think it's very serious.

The rich / lean fault code are unmetered air entering / escaping. This needs to be fixed ASAP. You need to find where the hole is You can get leak detector spray from Audi that suppressed combustion. You spray it where you suspect the leak is and it gets sucked in and stops the combustion so the engine runs rough and you know where the leak is. Don't know if they sell it to Joe Public though.

[JCviggen]

Thanks, I'm using VCDS lite (registered) no other option for me because if I had to buy it with one of their cables I wouldn't have it till end of december when I visit my home country again.

I've read about the EGT, that is unfortunate but not the most critical thing to run with for a bit I think...especially since WOT never lasts more than a few seconds around here. I'll ask around if any garage around here can swap it without pulling the block, I have faith in Russians pulling it off since they're not "by the book" people Will fix the air leak first though. I'm pretty sure it's actually running correct AFR's just its throwing the codes because it has to compensate more than what it considers normal. It has to be a somewhat sizeable leak to disrupt idle though and the CEL is bloody annoying.

[Shoppinit]

Yes. Weird thing is that your g/s numbers look OK at higher revs. Well, might be a little low.

I still think you need to check the MAF seating.