Power loss.. episode #6..

[Hy Octane]

Up until now we have been working on the theory that this intermitent power loss I have had since new is somehow linked to hot temps.. well, after Audi's last attempt to fix it failed, they told me to wait until the weather warmed up and we would try again ( it seems to happen less in cooler weather.. )..

A few weeks back I decided to start running her on a blend of 100 octane racing gas and regular 91 socal crap blending it to approx 93-94 octane..

The car has been pulling great and had no power losses.. until I filled up last week with Shell V Power 91 without the 100 oct.... A few minutes after pulling out of the station, with a still cool motor and cool outside temps, the beast did its trick...It resets after you restart the motor. It did this 3 times in the first 35 miles of this tankful, which also caused me to have to use alot more gas pedal to get it to move than usual.. I deduced that I must have gotten a bad tank of gas and then it hit me..
This is the exact same thing that has been happening!

So,

What component of the motor is responsible for cutting the boost and retarding the timing to this extent?
Bingo. The Knock sensors..

I ran over to Audi and verified with the tech that these sensors were indeed able to control the boost and timing and if they detect bad fuel, they will cut the power as I have been describing for almost 2 years ..The difference is that normally, knock sensors would temporarily reduce boost and timing to match the load and then return it to normal when you take your foot off ther gas..In my case, the timing and boost are retarded to minimum where they stay until you turn off and on the ignition...After running the bad gas out and having several more power cuts, I refilled with my 100+91 blend and not one hiccup since.. ( if the sensors dont have to intefere due to adequate octane and no knocking, then no problema, )

This is the first real clue as to where the problem might be as these knock sensors are really the only things in the motor that can be the culprit.. i am surprised that Audi didnt come up with this on their own having already replaced the ECU,thermostat, EPV purge valve, both MAF sensors and both exhaust gas sensors along with a few thousand test miles...

Of course yours truly had to come up with it and I'm really hopeful this is the deal.. Audi just called to ok the replacement and thanked me for being so patient..

She goes in monday.. I'll let you know how it all turns out..:mech:

[Benman]

Dang Paul,

I really think you should win the "Most patient RS 6 Owner Award". You've had crap with your Beast since day one! What a nightmare!

Now it seems you have the "crack whore" RS 6 junkie that is addicted to Octane Boost! She won't even get out of bed for anything less than 94 blend! And if you dare try, she runs like poo poo for you. Appropriate that your name is "HyOctane"!!!:bigeyes: (Murphy's Law!:p ).

Man, I swear, I really hope you can get all this crap sorted out. Very few would have had your patience, myself included.:cheers:

Ben:addict:

[Hy Octane]

Hey Ben!
Well, you dont know how many times I have come thissssss close to giving it back.. but, I really dont want the S6 or the RS4, and this car is such a beauty, and the fact that theres really nothing out there that can replace it, and there arent any more new ones, and if I do give it back to them they will eventually fix it and sell it to someone else to enjoy, and that turbo whoosh....

I just keep tellin myself that we'll find it and fix it soon enough..:mech: :mech: :addict:

[Benman]

Originally posted by Hy Octane


I just keep tellin myself that we'll find it and fix it soon enough..:mech: :mech: :addict:
Hang in there buddy...:cheers:

Ben:addict:

[nene]

That is amazing man. Great work. Unsure I could have put up with it for that long, so I won't lie to you. However, I am impressed, and because of your patience, we have all learnt a great lesson. Thanks for keeping us posted.


What dawned on you to all of a sudden add the 100 Octane?

[SoCal]

"HyOctane" indeed! Benman said it best.

Glad to hear that the mystery may be solved. I sure hope that you've found the solution and that your considerable patience will be rewarded with a problem-free Beast at last. :race: Quite a saga.

Just wondering...where in LA did you get the 100 Octane gas? I've used it at the track and on long drives home from the track, with really nice performance, but never bought it locally. I know there is a gas station in Santa Monica Canyon that carries it. Union 76 used to have it at a few outlets ages ago under the knickname "Blue", but it was discontinued when the 76 brand was sold (the first time) a little while back. Not sure where else it's available in town.

Good luck with the new knock sensors. :0:

[freerider]

You know, there is an alternative. Come and live in Europe, were the lowest octane is 95. Most people use 98 though. And if you really want, you can also get 100 and 102 (very expensive though) octane.

I really hope it get's fixed this time.

Greetz Johan

[CarbonFibre]

Originally posted by freerider
You know, there is an alternative. Come and live in Europe, were the lowest octane is 95. Most people use 98 though. And if you really want, you can also get 100 and 102 (very expensive though) octane.

I really hope it get's fixed this time.

Greetz Johan
Yes, fuel is better in Europe than in the US. Sometimes people make the differences seem higher than they are though as 87 octane gasoline in the US is equivalent to around 91 RON in Europe, so the numbers are a little different (different measurements).

[SoCal]

Originally posted by CarbonFibre
Yes, fuel is better in Europe than in the US. Sometimes people make the differences seem higher than they are though as 87 octane gasoline in the US is equivalent to around 91 RON in Europe, so the numbers are a little different (different measurements).

Right. There are different ways of rating octane. U.S. uses AKI, which is an average of RON and MON. Europe uses RON. MON is probably a better measure of real world operating conditions for performance engines.

“Octane” is a measure of a gasoline’s resistance to detonation. Tests for both the “research octane number” (RON) and “motor octane number” (MON) use a single-cylinder engine having a variable compression ratio. The engine is run on the gasoline to be rated and the compression ratio is varied to obtain a standard knock intensity measured by an electronic knockmeter. The octane of the sample is determined by comparing its knock tendency with that of reference fuels having known octane numbers.

The U.S. Federal Government requires octane of gas sold for road use be rated by an average of RON and MON (“R+M/2”) and that number must be on a yellow sticker applied to the gas pump.

Typically there is no performance gain from using a gasoline with a higher octane rating once you are above the minimum octane for the engine's detonation threshhold (i.e. above the point at which the engine "knocks"). The RS6 or any other car with knock sensors will retard detonation if octane is too low, so using higher octane (up to 96 AKI) helps somewhat compared to the minimum recommended 91 AKI octane gasoline, but there are no benefits to going higher than 96 or so.

From an Audiworld post:

"AKI is calculated as(RON+MON)/2. Example: RON=98 MON=88 (98+88)/2=93. RON = Reasearch Octane Number. MON = Motor Octane Number. RON is an octane rating test done with a motor running at a constant speed. While MON is test done with a motor with varying speeds. The MON is considerd a more accurate measure of a usable octane rating. So the US 93 octane is about the same as European 98."

That said, Europe still has frequently better gas, higher speed limits, wonderful scenery, more models of cars worth driving.... All in all, you've got it good.

[Hy Octane]

Hey Socal..
You can get 100 racing gas at the 76 station on Bundy and San Vincente. Its $6.40 a gallon.. The old Canyon Gas station on 7th street is no longer there..While 76 no longer produces the 100 racing gas, they have an independent supplier who still stocks the 76 stations with it.. Theres another on barringon and Pico, but that guy is really greedy and charges $7.50+ plus a gallon..

The blending I use is 3 gallons 100 for every 6 gals 91.. this comes out to 94 oct..

[BBGT2]

Audi of America should give you another car just for being that patient with yours for this long.
I for one for sure wouldnt have stayed with the car that long, you must have nerves of steel, what do you do for a living you must be a brain surgeon.
Glad to hear you narrowed it down and from what I have read did Audi's work for THEM, another reason whay they should give you a car for free, you got my vote.

Good Luck,

Bajo:addict:

[Finnus]

Audi of America should give you another car

Yeah, the NEW RS6! LOL

Finnus
:addict:

[BBGT2]

Originally posted by Finnus
Yeah, the NEW RS6! LOL

Finnus
:addict:


They shouldnt make him wait THAT long.:D

[Hy Octane]

Well, I could have an RS4.. but I dont like the S6 much especially with a detuned V10..But I really love this car.. I mean, except for this nagging engine problem which has been there since birth, the car has had very few other issues.. just your regular teething stuff..
I tried to switch away from quattro but after 16 years of nothing but Audi's, but honestly, I cant go back.. This is my 4th Audi.. out of these 4, 3 were lemons.. Thats right.. My first Lemon was a 91 200 20v Quattro that had so many repairs under warranty that it exceeded the price of the car.. Audi replaced it with a 94 S4 which I still have.. This car only had minor problems and it will be my sons first car.... Lemon #2 was a few years ago when I bought a 2003 A6 4.2.. After 10k, the motor let go and after Audi rebuilt it, it ran like crap.. So They replaced it with this Lemon #3.. I know we will get it fixed and then it will be behind me.. So, you can see that over the years I have learned to be patient with them.. Gotta believe good times are just around the next bend....

[iconcls]

Originally posted by Hy Octane
This is my 4th Audi.. out of these 4, 3 were lemons..

You have to admit, statistically that's really unbelievable.

[Benman]

Originally posted by iconcls
You have to admit, statistically that's really unbelievable.
No kidding, that is like the exact opposite of "Some guys have all the Luck"!!! Well, now we know where all the bad luck went! Poor Paul.:cheers:

Ben:addict:

[Bauer]

Originally posted by iconcls
You have to admit, statistically that's really unbelievable.

agreed!!

Cars get too complicated for their own good sometimes.

[xscream]

The drivers manual of my RS4 said that you should not drive the car with worse fuel than EU 98.
I belive the manual for the RS6 is also recomended to use 98, althouh it can be driven on 95. (93 vs 91)

Maybe there is nothing wrong with the knock sensors, they might just be doing their job protecting your engine.

Keep on driving on your mixture and see if you have the problem again, if not, you just have to drive the car on its recommended octane. :)

[Hy Octane]

Gas door flap says US 91 oct is minimum..If this were true then all of us here in Socal would be having the same issues, no?

Problem is that the way they meter the additives is very unscientific and octane can vary from tankerload to tankerload.. Since we are operating at the lower end of the octane scale, there isnt much room for fluctuation as has happened to me.,. These cars are very sensitive to this stuff and I am hoping that one of the 4 sensors is faulty from birth.. We'll know by the end of this week..

[CarbonFibre]

Originally posted by Hy Octane
Gas door flap says US 91 oct is minimum..If this were true then all of us here in Socal would be having the same issues, no?

Problem is that the way they meter the additives is very unscientific and octane can vary from tankerload to tankerload.. Since we are operating at the lower end of the octane scale, there isnt much room for fluctuation as has happened to me.,. These cars are very sensitive to this stuff and I am hoping that one of the 4 sensors is faulty from birth.. We'll know by the end of this week..
Even with variations like that the 91 pump gas should still be working fine without the problems you are having. I would say it's still something else besides purely the fuel.

[Rupert]

I also have the power loss "feature".

When accelerating WOT from a standstill, at around 5k revs in 1st gear the boost is cut and the car feels like it has <300BHP. This continues for a time, sometimes as little as 1 minute. Constantly prodding the pedal to get it to kick down seems to make full power return sooner. It also happens at the top of 2nd and 3rd gears. It seems to be hit and miss - sometimes when I have been testing the car it has happened five times in a row, then it won't do it again for a week. Turning off+on the ignition does not help in my case, and there are no warning lights on the dash. It does not seem to happen if I change gear using the paddles lower than about 5k before it changes on auto.

I'm sure it's not related to the fuel, it happens on 99 RON (UK RON) pump fuel with octane booster - enough OB to raise it to about 104RON. I certainly don't use OB all the time, I only started experimenting with it when I experienced the power loss, plus it already costs over $130 for a tank full!
:eek:

[mmaturo]

Hmmm, your car sounds like it is doing what mine was. When jumping into it even a little bit (on ramps to the interstate or stop lights) I would spool up to 4 to 4.5K and the point where the second gear shift was to occur and the turbos would cut out and was then going with no boost up the gears or sometimes held at the rpm in first. Happened up to 3 out of 4 runs. Turned into transmission problems. Threw a code for the torque converter giving up on life finally after a few months of it. Then the trans. After both replaced that particular problem seems to be gone. Seems may have been the transmission telling the engine not to give it too much power and shutting down the turbos to protect itself (turbos were overboosting).

[SoCal]

Originally posted by Hy Octane
Hey Socal..
You can get 100 racing gas at the 76 station on Bundy and San Vincente. Its $6.40 a gallon.. The old Canyon Gas station on 7th street is no longer there..While 76 no longer produces the 100 racing gas, they have an independent supplier who still stocks the 76 stations with it.. Theres another on barringon and Pico, but that guy is really greedy and charges $7.50+ plus a gallon..

The blending I use is 3 gallons 100 for every 6 gals 91.. this comes out to 94 oct..

Thanks! :bow: I appreciate the info and will be sure to get over there to fill up soon.

With all those lemons you've made lemonade. Your patience and brand loyalty in the face of all that is quite remarkable. Yes, these are awesome cars when they work right but, wow, what a run of troublesome issues you've had. Reading these posts makes me feel lucky never to have had problems like that with my Beast.

[Benman]

Originally posted by SoCal
Reading these posts makes me feel lucky never to have had problems like that with my Beast.
Amen, Paul, an inspiration to all of all! :bow: :p

Ben:addict: