S6 carbon cleaned. Now if

A6 All/ S6 All
#1

Just got done doing an extensive carbon cleaning. I just got the car a little over a month ago and went ahead and did the cleaning myself. Added intake spacers while I was in there.

Here are my issues now. I’m getting random check engine lights when I do a cold start. It idles like it’s misfiring but when I rev the engine a little it seem fine. Its also randomly getting a high idle. It will go up to about 2k rpm and just sit there. It cruises down the interstate just fine. Once it was warmed up and I was on the interstate it drove fine. No check engine lights on the drive home from work. All I did was clean the carbon out of the valves and off the ports in the manifold where it meets the head.
I know I probably have some intake flaps broken and hope to fix that at some point. Prior to taking things apart and cleaning the engine ran fine. Idled perfectly and drove very smoothly. I can’t figure out what I could have messed up while I had it apart. If anything I was expecting it to run better. The transmission is not got the bad lurching when i’m in traffic and it downshifts. Although I think some of the lurching may be due to the high idle.

Any suggestions?

#2

Welcome to the forum your in the right place.

first good way to start is to help post what codes the car is getting. Those should help put us in the right driection to give you actual feedback on what is happening to the car.

Its not uncommong to pull the intake and create a small leak in the PCV line.

Something you can try is go check your intake bolts and make sure none of them have backed out. usually when you see high idle that is a good indication of a vac leak

The intake spacers are the right move and that will really help keep the car and the motor happy.

#3

Last start up was when I was leaving work. I got misfire codes on cylinder 3,4,6,7,8,9,10 and P2004 and P2005 which are the manifold runner control stuck open. I have a feeling the runner errors could be related to the bad idle and losing vacuum

#4

My guess is that you have the same problem I did when I added the intake spacers—a clearance problem with the runners causing the P2005. There is a wiring/vacuum hose mounting bracket on the front, driver-side of the raised IM that may block the runner servo from fully opening. If so, take it out or raise it with a nut as a spacer.

#5

This could be the bracket Mixofia is talking about

http://audirevolution.net/forum/index.php?topic=3950.msg116287#msg116287

If you have not already read the entire thread. It is a good step by step on what you should know and do to your S6

http://audirevolution.net/forum/index.php?topic=3950.0

#6

I just went and started the car. Seemed to idle mostly fine for about a minute then got this surging idle up and down between 600 and 1000 rpm. Then I got a CEL after a bit got the runner again. I think it happened because of losing vacuum. I’ve got a rushing air sound on top of the plenum between the throttle bodies. But I cannot feel any gaps that would tell me there is an air leak. May just pull it off anyways and reseat it.

I assume a vacuum leak would cause this surging idle?

#7

The flaps are motorized so there is no vac that would cause those to not work. Check the plugs and check to make sure the brackets in the link I showed you are removed.

You can check for vac leaks a few ways. One of the simple ways is to go buy starter fluid and spray it in the area you think there is a leak. If the leak is big enough the RPM will rise. Or you can use soapy water and spray that around to see if you get any bubbles.

RPM surge usually is something you see with vac leaks.

#8

Check if you installed the manifold gaskets correctly they are two spacers they look the same but i think they are slightly different (not sure but worth the check ) one is for the left and the other is for the right and also the installation direction. Check if you have installed it the correct way like up and down and not the opposite direction. Also check if any screws on the intake are loose i think ones you install the spacers you need to drive the car hard everything will settle in and the. You need to re tight the screws again, maybe one screw is loose and it’s causing the leak

#9

I know its a stupid question. .is it possible you could have an S6 for 80-90k and it not need a carbon clean?

There must be people driving around out there completely oblivious to the carbon clean issue (not just v10) who are very happy with the way their car is… sure they my have slight loss of performance - will they even know?

#10

The thing that is hard about carbon is that it’s not going to be the same on every car. Almost every case of carbon build up is going to be different. But lots of these cars have made it to 90k miles without cleaning but now those cars are seeing issues with pinging misfires cold start issues and damaged injectors.

So its possible but if you let carbon go too long unchecked youll have an issue sooner or later.

#11

So I found my issue. The PCV hose on the driver side had a big split in it. Found it taking the intake hose off. Easy fix and it runs so much better now.
My mpg increased as well. Before I was getting about 150 miles when my needle was getting to half. Now i’m at about 210 and I’m showing half a tank.

Only issue I’m having now is the P2004 and P2005 codes . weird thing is the past 2 days I never get them on my drive to work in the morning but get them when I’m leaving the office in the afternoon they show up .

#12

I think this is my problem with the servo arm hitting the bracket. How exactly did you raise it?

#13

I put a hex nut under the bracket to lift it a little higher. I think I only have it attached at the vertical stud. But it seems to do the trick.

#14

I’m having P2004 and P2005 errors since a recent clean and IM spacer being fitted. I’ve been able to check with VCDS and the actuator arm is opening fully, but can jam open and takes a long time to re-close again?

Is this the same problem you guys are seeing? I mentioned about a hose that may need adjusting to my garage/mechanic but he said there was no issue?

#15

http://i60.tinypic.com/2lvl6y8.jpg

This bracket was causing problems for me. I filed out he T30 and the 10mm holes so that the bracket could move up a little and away from the arm. Since one end of the bracket is mounted to the head and one end mounted to the intake and you install the intake spacers it causes the arm to just hit the bracket. I believe it tries to open and once it gets stuck it doesn’t try anymore and throws a code. After modifying the bracket a tad I haven’t gotten any codes since.

#16

Yes either remove the bracket or midify to clear the intake arm

#17

still haven’t figured out my misfire issue. I connected VCDS and checked the measuring blocks to see which cylinder was giving a misfire and cylinder 8 was missing pretty frequently. Only thing I have not done is checked the gap on the plug. I replaced the plug awhile back with OEM plugs so maybe this one didn’t get gapped right when it was made.

I’m in the process of replacing my radiator also. Went ahead and replaced the belt and also the front main seal… Anyone have the torque spec on the 8 bolts that hold the crank pulley on? JHM lists 20 foot pounds when using their lightweight pulley. Also is blue Loctite sufficient for the bolts? I cant imagine any need for red Loctite .

#18

still haven’t figured out my misfire issue. I connected VCDS and checked the measuring blocks to see which cylinder was giving a misfire and cylinder 8 was missing pretty frequently. Only thing I have not done is checked the gap on the plug. I replaced the plug awhile back with OEM plugs so maybe this one didn’t get gapped right when it was made.

I’m in the process of replacing my radiator also. Went ahead and replaced the belt and also the front main seal… Anyone have the torque spec on the 8 bolts that hold the crank pulley on? JHM lists 20 foot pounds when using their lightweight pulley. Also is blue Loctite sufficient for the bolts? I cant imagine any need for red Loctite .

#19

Is cylinder 8 the only one missing? If so is it just missifreing on cold start or all the time even when driving.

#20

After it was fully warmed up it was still having misfires. Its sometimes doing it on coldstart as well. I pulled up all of the measuring blocks to watch each cylinder and 8 was the only one that was frequently registering a misfire. I did not sit and watch it while driving. Its hard to keep track of and the counter resets randomly for some reason. I just don’t see a reason for the car to misfire so frequently on a specific cylinder when the car is fully warmed up and just idling. Like I said, I need to check the gap on the spark plug. Just got done replacing the radiator and just haven’t gotten around the pulling the plug out yet. Plugs were replaced about 18k miles ago with OEM plugs and not too long after I replaced all the coils. It shouldn’t have a reason to be misfiring. Only guess is the gap is maybe off on that plug. I did a carbon clean less than 2k miles ago. I’ve even checked for oil around the plug, cleaned everything, even swapped in an old coil just to see if that made any difference. Where to next?

Also has anyone tried out the new JHM transmission tune?