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Power loss at higher revs
Posted: Wed Feb 02, 2011 11:17 pm
by Mancmatt
Hey guys.
I've a strange issue and wondered if anyone knows what may be wrong.
My RS6 seems to have lost power at around 4500rpm. Kickdown seems fine and car shoots up to a certain point then boom - the last 2000RPM or so it feels dead - like an old diesel! It's almost as if it drops into top gear when it shouldn't but I don't think this is happening as the issue remains in paddle mode.
Do the turbo's kick in sequentially? Have i lost one of them perhaps? My missus drives the car mostly so it's very rarely run at high revs - she hadn't even noticed the issue!!
Any suggestions appreciated. Cheers.
RE: Power loss at higher revs
Posted: Thu Feb 03, 2011 8:56 am
by Shoppinit
It is time to buy that most useful of RS6 tools... a vagcom.
Start by checking:
MAFs
N75
DVs
Intercoolers
You didn't put 95 octane in, did you?
RE: Power loss at higher revs
Posted: Thu Feb 03, 2011 10:14 am
by RS6Steve
As he said. The best £300 you will spend for a 6.
Mine saves me a fortune or cost me a fortune as I now know exactly whats going on with it.
RE: Power loss at higher revs
Posted: Thu Feb 03, 2011 10:25 am
by Rupert
The turbos are not sequential, there is one for each half of the engine.
Mine had a problem where the acceleration would tail off towards the red line, in fact it would take (what seemed like) an age to get there.
The lower revs were OK at the start of this problem, it would have more torque when it changed into 3rd gear than it had at the top of 2nd gear.
It wasn't long before the emissions light came on, and the idle revs were high, so it would happily pull along at 30-40mph at idle speed.
In my case it was the O2 sensors in the exhaust.
RE: Power loss at higher revs
Posted: Thu Feb 03, 2011 10:36 am
by Shoppinit
Engine out job?
Friend of mine managed to change his rear lambda sensors without dropping the engine. FYI

Don't think the 2nd sensors have any effect on engine power though, just there to check the health of the cat.
RE: Power loss at higher revs
Posted: Thu Feb 03, 2011 10:39 am
by Doug_S2
You can change any egt or lambda and get the orignal clips for the lines back on without removing the engine.
I am sure vagcom will show a lambda or egt, or you have a one way valve gone or hose split
Re: RE: Power loss at higher revs
Posted: Thu Feb 03, 2011 12:03 pm
by Rupert
Shoppinit wrote:Engine out job?
Friend of mine managed to change his rear lambda sensors without dropping the engine. FYI

Don't think the 2nd sensors have any effect on engine power though, just there to check the health of the cat.
According to the book yes, but they can be changed with small hands and grazed knuckles.
Apparently they were contaminated because of faulty coil packs (one on each bank).
Re: RE: Power loss at higher revs
Posted: Thu Feb 03, 2011 7:10 pm
by Mancmatt
Rupert wrote:The turbos are not sequential, there is one for each half of the engine.
Mine had a problem where the acceleration would tail off towards the red line, in fact it would take (what seemed like) an age to get there.
The lower revs were OK at the start of this problem........In my case it was the O2 sensors in the exhaust.
This is exactly what mine is doing! Hopefully it is something this simple.
I will invest in the Vagcom soon. Short term though, I'm due a service so will book it in with Grizz and let him take a look while he has it. Praying that it's not an engine out job!
Thanks for feedback guys.
Posted: Thu Feb 03, 2011 7:27 pm
by chunky79
Where in the midlands are you mate? I have
Vagcom and can whack it on your motor if you want. I don't know what the hell to do with it but can try and help
dunc
Posted: Thu Feb 03, 2011 8:57 pm
by grizz
We don't remove the engine for egt's or lambdas ..
Posted: Fri Feb 04, 2011 4:20 am
by Mancmatt
OK. Thanks grizz. Will call you to book. Hopefully you have an angle grinder to stop it shredding tyres too? ATS won't do it!