I'm going to drive this rs6 over a cliff.

[peiserg]

my car has OCT software, MIlltek racing cats and catback exhaust, as well as an aquamist intercooler water injection system.

a couple months back, the car developed some symptoms, where at WOT the power felt like it was being cut back by 50%. Originally it was only in 3rd gear at 82mph, but later occurred, intermittently, in 1st, 2nd, 3rd, and 4th.

VAGCOM told me a couple things..

Intermittent HVAC flapper valve problem. I guess that's unrelated, more like an air conditioner issue? Don't know, since my AC and heater work fine.

Intermittent boost pressure exceeded

Torque converter failure/no power transmitted

So the torque converter was fixed. along the way got the 35k mile service done. Total bill $6200. $4200 for TC, $2000 incl parts ($1000) and labor ($990) for the 35k mile service.

On the drive home (after sitting there for a month in the shop), the same goddamned symptoms.

Pulled out my trusty VAGCOM (best $300 ever spent) and my TC failure is not there, but all the other codes are.

The service guy thinks the car is overboosting, and then cutting off boost as a result.. which gives me a sudden drop in power.

I don't know what to make of the other issue (HVAC).

I've had OCT for 22000+ miles. IS it possible it's now causing a problem?

I'm going to take it to race technik, where i had it flashed to OCT, to have it reflashed to stock and see if that helps.

IS there anything on vagcom i can monitor, any blocks, that would help the service dept elucidate the issue further?

I'm so pissed right now! $6200 and same fkn issue. yeah, i know.. $2000 of it was routine service. but still!

[DHall1]

That does suck.

If its any help and you want to come down to Casa Grande. We can run back to back runs with the Vag hooked up and go back and forth between my 100% stock RS6 and your modded RS6. Compare data from logs. There are a ton a open roads to perform back to back runs after runs.

It could be something as simple as a boost line leak to the wastegate causing the wastegate to stay closed and not open on time.




my car has OCT software, MIlltek racing cats and catback exhaust, as well as an aquamist intercooler water injection system.

a couple months back, the car developed some symptoms, where at WOT the power felt like it was being cut back by 50%. Originally it was only in 3rd gear at 82mph, but later occurred, intermittently, in 1st, 2nd, 3rd, and 4th.

VAGCOM told me a couple things..

Intermittent HVAC flapper valve problem. I guess that's unrelated, more like an air conditioner issue? Don't know, since my AC and heater work fine.

Intermittent boost pressure exceeded

Torque converter failure/no power transmitted

So the torque converter was fixed. along the way got the 35k mile service done. Total bill $6200. $4200 for TC, $2000 incl parts ($1000) and labor ($990) for the 35k mile service.

On the drive home (after sitting there for a month in the shop), the same goddamned symptoms.

Pulled out my trusty VAGCOM (best $300 ever spent) and my TC failure is not there, but all the other codes are.

The service guy thinks the car is overboosting, and then cutting off boost as a result.. which gives me a sudden drop in power.

I don't know what to make of the other issue (HVAC).

I've had OCT for 22000+ miles. IS it possible it's now causing a problem?

I'm going to take it to race technik, where i had it flashed to OCT, to have it reflashed to stock and see if that helps.

IS there anything on vagcom i can monitor, any blocks, that would help the service dept elucidate the issue further?

I'm so pissed right now! $6200 and same fkn issue. yeah, i know.. $2000 of it was routine service. but still!

[hahnmgh63]

Download the full VAGCOM manual. You can go into a data logging mode and do some acceleration runs and pick a bunch of parameters to be logged. I think engine TQ and some transmission parameters are there as well as boost.
I occasionally get an intermittent overboost which I clear but only comes back after I have driven the card hard. Mine has Revo chips and about the same chipped miles as you. Maybe yours is overboosting a little too much and going into limp home mode. I think Vagcom can tell you more in data logging mode than just reading the codes. It would be a long explanation for me to go into on how to set it up for data logging so it would be best for you to download the Vagcom manual and read about the data logging so you can set yours up. You can also set it up to log 0-60 times and 1/4 mile times, I've found it is pretty accurate. Post what you find please.

[peiserg]

Download the full VAGCOM manual. You can go into a data logging mode and do some acceleration runs and pick a bunch of parameters to be logged. I think engine TQ and some transmission parameters are there as well as boost.
I occasionally get an intermittent overboost which I clear but only comes back after I have driven the card hard. Mine has Revo chips and about the same chipped miles as you. Maybe yours is overboosting a little too much and going into limp home mode. I think Vagcom can tell you more in data logging mode than just reading the codes. It would be a long explanation for me to go into on how to set it up for data logging so it would be best for you to download the Vagcom manual and read about the data logging so you can set yours up. You can also set it up to log 0-60 times and 1/4 mile times, I've found it is pretty accurate. Post what you find please.

I already know how to log via the vagcom, i am just unsure what it is I should log.

One thing that is irritating as hell is that it is intermittent.. The dealer was only able to reproduce it once or twice, but that was after a week's worth of occasional driving.

I guess the issue is the overboost? But what is causing it? Dealer wants to replace the turbos... they wanted to do that along with the TC but fidelity wouldn't pay for it at the time. now the TC is fixed, and the problem isn't, so the warranty company may be about to eat another $2000 in labor.

I really do appreciate the offer to do some runs in casa grande. I may just take you up on that. Is the best time on weekends, or afternoons, or what? My schedule is labile, almost never the same day to day. Tho i do have this weekend off, so maybe we can do something if my wife doesn't get bent out of shape about me leaving for a few hours.

I think what really gets me is... a MONTH in the dealer... (4th trip for same problem BTW!) and same issue... they did give me a nice loaner, and told me they wnated to do the turbos but couldn't.. so i don't lay this entirely with them.

[DHall1]

Bring the Vag and your laptop. I will be around this weekend. There are lots of good paved county roads around CG for testing. I have plenty of space, jacks, ramps, tools and garages to check things before and after. I have found that when hunting for problems such as this....its always better to have 2 heads in the game esp when you trying to drive and diagnose at the same time. I have done hours and hours of road tuning over the years. From stand alone systems to reflash systems such as Cobb software. Data logging most always reveals the problem.

Early is no problem. Thats generally best when it comes to getting time off from the Mrs.

Which dealer works on your car? I was up in Chandler today picking up some stuff at the Chandler Audi,Benz and Lexus. Just doing my part to keep the economy going. I think I gave them 1100 dollars. :-) At least they give me 15% discount now. The parts guys are cool at Chandler Audi but I dont know about the service writers yet....not too impressed so far.

Next weekend is the meet in CA and were planning a few days in So Cal while were over there. So, this weekend may be best.

LMK

dhall1@vzw.blackberry.net

Dave


I already know how to log via the vagcom, i am just unsure what it is I should log.

One thing that is irritating as hell is that it is intermittent.. The dealer was only able to reproduce it once or twice, but that was after a week's worth of occasional driving.

I guess the issue is the overboost? But what is causing it? Dealer wants to replace the turbos... they wanted to do that along with the TC but fidelity wouldn't pay for it at the time. now the TC is fixed, and the problem isn't, so the warranty company may be about to eat another $2000 in labor.

I really do appreciate the offer to do some runs in casa grande. I may just take you up on that. Is the best time on weekends, or afternoons, or what? My schedule is labile, almost never the same day to day. Tho i do have this weekend off, so maybe we can do something if my wife doesn't get bent out of shape about me leaving for a few hours.

I think what really gets me is... a MONTH in the dealer... (4th trip for same problem BTW!) and same issue... they did give me a nice loaner, and told me they wnated to do the turbos but couldn't.. so i don't lay this entirely with them.

[hahnmgh63]

When you bring it up you can choose different things to log and do more than one run and save the files. Obviously do the N75 valve, boost, TQ, I would also do all 8 cylinders for misfires. I don't remember all the parameters you can log off hand but 2 and maybe 3 runs should cover all your bases and get the car to respond they way your expecting. Maybe 0 to 80mph on a desolate road. You don't mention total miles on the car but say you've just had the 35K service so I can't possibly see how the Turbos could be bad. KKK are pretty reliable Turbos. With the codes you've listed, I would start by the software rollback that you mentioned. Although, how long did you have the OCT before this occurred? Maybe replace the N75 valve and check some of your vacuum hoses. I just had my aircleaner off and replaced many of the vacuum hoses with better silicone ones as they were already showing deterioration at 50K and I almost always open my hood to let it cool after I drive it. I also did the N75 valve and of course the Air Filters while I was in there. While the housing was off I sprayed a little Gunk Carb cleaner at the Massflow sensors to help clean them too. The N75 valve is a relatively cheap try? You may try logging it with Vagcom first.

[mmaturo]

Your symptoms are exactly what my car did before and on TC failure number one and number two but on two the transmission went with it. My turbos were replaced but that was due to a frozen mount on one when getting the engine and trans out. It was overboost but really was the trans/TC telling the engine it was getting too much power so shutting it down. However in my case the second TC and trans replacement did it. No other leaking anywhere which is what they spent 3 months looking for at various service departments till one of them figured it out.

[peiserg]

thanks for the responses so far.

I do have a brand new n75 valve and boost sensor as part of the trouble shooting.

I have had OCT for about 22000 miles, totally trouble free.

i might try to get to casa grande tomorrow, but there's no way i can reflash to stock ECU... although since we have the stock car (yours), perhaps we can use that as a baseline.

gerry

[grizz]

Log your requested & actual boost levels . I think it's block 115.... I would say n75 valve ..

[peiserg]

my "old" n75 valve was replaced at 7000 miles. it had 25000 miles on it, and was replaced at 32000 miles. car now has 32100 miles. the replacement made absolutely no difference whatsoever.

[DHall1]

If we data log tomorrow and boost levels are stable. Then we can focus on trans operation and the situation that Mark was talking about.

If the trans is slipping we should be able to feel it. Esp if we can go back and forth between a known stock car with no problems and yours that has this problem. I can understand the ecu going into limp mode after a transmission failure or slippage. The ecu is just a computer. There has to be a slippage of the transmission where the rpm goes up and the speed does not change in relation to the gear of the trans. We should be able to feel that.

Again, thats after we data log to determine boost levels are stable and all the other logs look good.


my "old" n75 valve was replaced at 7000 miles. it had 25000 miles on it, and was replaced at 32000 miles. car now has 32100 miles. the replacement made absolutely no difference whatsoever.

[DHall1]

Ok,

Grizz et al

We did perform data logs today.

The problem is overboost. All numbers in Mbar

The boost called for number is steady at 1700 up to 2100 as the rpms gain.

The actual boost number follows those orders until higher rpm and gears then all of a sudden spikes to 2400 and the ECU shuts down boost all together.

Again, the car pulls fine thru the gears and actual boost stays inline with called for until higher load and higher speeds say in 4th gear or so and then the spike occurs.

So, a couple of questions come to mind. What are stock values for boost? What is the trigger point for overboost? I assume in the range of 2400 because thats where the ECU cuts off. So in the range of 21psi for a cut off.

Gerry is going to have the OCT reflashed to stock next week and repeat the test. If its a hard problem with turbos or wastegate lines leaking then it should reason the problem will still be there.






If we data log tomorrow and boost levels are stable. Then we can focus on trans operation and the situation that Mark was talking about.

If the trans is slipping we should be able to feel it. Esp if we can go back and forth between a known stock car with no problems and yours that has this problem. I can understand the ecu going into limp mode after a transmission failure or slippage. The ecu is just a computer. There has to be a slippage of the transmission where the rpm goes up and the speed does not change in relation to the gear of the trans. We should be able to feel that.

Again, thats after we data log to determine boost levels are stable and all the other logs look good.

[hahnmgh63]

I would definitley check the wastgate lines and trace them to the N75 valve since it sounds like his N75 valve was replaced once or twice. Somebody has had the filter housing off and working on the car. Did this start after his timing belt/waterpump change? Seems like it wouldn't be the chips if they were working fine for many miles but never know.

[DHall1]

Yep, those are my thoughts exactly.

We poked around what we could see but didnt take the air filter housing off all the way. What is the trick to get the bottom of the air filter housing released from the MAF sensors??

We had several ideas and after I watched the realtime data as the problem was happening it all but removed any fingers pointing to the "OCT chip". Also, this did not happen after a timing belt or major service.

I also point the finger to the N75 and lines down to the wastegate actuators. It also could be the diaphragm in each wastegate valve. This is an AZ car and it gets hot down here. Those suckers got to be red hot with heat soak in the summer. That will shorten the life of the wastgate valves.

What sucks here is that the engine was just out and they could have caught this problem before pulling the engine. Now they may have to do it again and replace those turbos.




I would definitley check the wastgate lines and trace them to the N75 valve since it sounds like his N75 valve was replaced once or twice. Somebody has had the filter housing off and working on the car. Did this start after his timing belt/waterpump change? Seems like it wouldn't be the chips if they were working fine for many miles but never know.

[hahnmgh63]

The bottom section of the aircleaner has the front center hex bolt to remove then a nut (10mm socket) towards the front on either side, nothing in the back except the MAFS. Once the 3 fasteners are removed just slightly rock the housing back and forth while lifting and the MAF seals will finally release. The MAFS are bolted to the lower filter section and they go into O-ring sealed intake tubes which stick a little. If they are dry when you pull it off lubricate the O-rings with some silicone grease before re-installing the air cleaner section. I would recommend to replace most of the vacuum lines that are easily accessible under there (especially the small dia. ones) with silicone hose. Keep us updated if you find anything.

[peiserg]

thanks for the input guys.. and to dhall for taking a chunk of his sunday to troubleshoot with me.

I've got a call into Doug Chernis at race technik. He did the aquamist and OCT chipwork. He texted me, said he'd call me on monday.

The problem started in November. I had a ABS light coming on. TOok it to dealer. they changed a brake sensor. On the drive home, it happened for the first time.

Took it back. No engine codes. They checked for loose fittings etc. Gave it back after a week. Same problem. Took it back 2nd time. Replaced the boost sensor and N75 valve. Same problem. Finally got a TC code, and Overboost code. They wanted to replace TC and turbos, but Fidelity warranty wanted codes to recur. While waiting to go back to dealer, had brakes and a 3rd injector for aquamist installed by Doug at race technik. Took car back for FOURTH time, they did the TC, plus the 35000 miles service. Fidelity would NOT cover turbos yet, so they only did the TC. Their argument was the TC issue was causing the overboost.

Now I wonder if the OVERBOOST cause a power surge to fry the TC?? Possible? I had the power loss for 6 WEEKS!! before my TC failure was noted by the computer.

Is there ANYTHING ELSE I should log, before I call dealer back? I did boost request vs. actual, along with RPM, and g/s.

gerry

[DuckWingDuck]

does the aquamist do anything?

[DHall1]

Gerry does say it helps big time in the summer. I looked over the setup and can give my thumbs up. I like it. If the summer heat kills too much power I may consider that setup.

The water inj is turned off for all this testing becuase its an overboost problem and the WI plays no role in the overboost.


does the aquamist do anything?

[grizz]

I use a vac pump on the actuator pipes , One pair go the the turbo comp side , The other pair go to the actuators.
These can be worked by hand.
I've had one car that had a split in the hose .I managed to replace both actuator pipes with the engine in place .....

It took a few hours but better than pulling the engine ....

[peiserg]

I use a vac pump on the actuator pipes , One pair go the the turbo comp side , The other pair go to the actuators.
These can be worked by hand.
I've had one car that had a split in the hose .I managed to replace both actuator pipes with the engine in place .....

It took a few hours but better than pulling the engine ....


that's exactly what the tech at race technik said. He was pretty irritated that they didn't do that when the engine was out, it would be so easy. In fact, I asked them to replace any lines that look questionable... I should have said "Replace all the vacuum lines that could cause this."

oh well. I have a concensus of 4 techs now, including dhall1... wastegate or vacuum line to said turbo. Car going back to stock boost level today. I'll log again, but I don't think it will change anything.

OH FOR THE PEANUT GALLERY...

Doug mentioned that the vacuum lines are SILICONE. everyone talks about "replacing the vacuum lines with silicone." the ones on the wastegates are already high temp resistant silicone.

[DHall1]

Yep, it sounds like he knows what he is talking about. Doug/right? And yes he should be irritated because 1. The engine was just out and 2. See my point below about the TC.

Its too bad alittle more diagnosis was not applied before going "all in" with the TC and pulling the engine/trans.

No way a bad TC could cause overboost. Never.

Even the two of us without knowing squat about Vag-com could figure this out in 30 minutes. :doh:

Hey, it could still be those actuators on the turbos.




that's exactly what the tech at race technik said. He was pretty irritated that they didn't do that when the engine was out, it would be so easy. In fact, I asked them to replace any lines that look questionable... I should have said "Replace all the vacuum lines that could cause this."

oh well. I have a concensus of 4 techs now, including dhall1... wastegate or vacuum line to said turbo. Car going back to stock boost level today. I'll log again, but I don't think it will change anything.

OH FOR THE PEANUT GALLERY...

Doug mentioned that the vacuum lines are SILICONE. everyone talks about "replacing the vacuum lines with silicone." the ones on the wastegates are already high temp resistant silicone.

[peiserg]

ok, as an update...

I had the car flashed back to stock. The first time I drove the car after that, the power drop off was the same the first couple of times I got into the throttle. After that, I was able to drive for 3-4 more days with no discernable issues.

I took it back to the dealer, and they have now changed out some wiring between the ECU and N75 valve, as well as the wastegate solenoids. I'm hoping the fix is in!

One thing I noticed on closer inspection of my data logs.. Initially, all i did was look at the portion corresponding to the power loss.. This showed boost levels hitting 2400 mb before shutdown. However, in looking over the entire log, there were plenty of times when the ecu was asking for 1500mb and receiving 1800mb-2000mb. I never noticed, because that is below the "limp mode" trigger point.

I pointed those portions out to the service advisor when i dropped off the car.

fingers crossed!

[DHall1]

Gerry,

Good news if its fixed. Just to close the loop on this.

Wastegate solenoids=Wastegate actuators ??

I just want to make sure we are talking about the same things. Its the round metal housings with the diaphragm inside.

Give us all the good news when its fixed.

Dave


ok, as an update...

I had the car flashed back to stock. The first time I drove the car after that, the power drop off was the same the first couple of times I got into the throttle. After that, I was able to drive for 3-4 more days with no discernable issues.

I took it back to the dealer, and they have now changed out some wiring between the ECU and N75 valve, as well as the wastegate solenoids. I'm hoping the fix is in!

One thing I noticed on closer inspection of my data logs.. Initially, all i did was look at the portion corresponding to the power loss.. This showed boost levels hitting 2400 mb before shutdown. However, in looking over the entire log, there were plenty of times when the ecu was asking for 1500mb and receiving 1800mb-2000mb. I never noticed, because that is below the "limp mode" trigger point.

I pointed those portions out to the service advisor when i dropped off the car.

fingers crossed!