Lost 50hp, where to look?

[Nige_RS4]

A hiss usually means knackered bypass valves - replace the OEM 710A valves's with 710N's from the TT, they are less prone to tearing. Do you have any lag when changing gears, as this is a common symptom of bad valves?

[SimonC]

What's the easiest way to get a look at the valves? Visibility is poor from above. Is it any better from below? The hiss I describe is not loud. Can't be heard with windows up, can just hear it with windows down. Surely even a recirculating system will "whoosh" on the overrun?

The link below describes what I believe I am hearing. I'm sure EVO, Top Gear or one of those mags ran a similar article recently.

http://www.lexusownersclub.co.uk/forum/ ... 29047.html

[Devil]

no yhe hiss is not very loud with mine either, windows down , then you can here it. I don't have VAG-com but can use VAG 5051 but does anybody know wich blocks to log on.?

[flashyg]

disconnect both of the dv vacuum hoses that meet in a tee, suck on the tubes , if this does not open / (you'll hear it) close the dv or keep a vacuum they are the cause.

[Devil]

I got me some Forge dv's today , but i don't think its much off a difference
Can somebody say if they sold me the right ones because its a really tight fit.

[Nige_RS4]

The original 007Ps are a better fit - which version are these - diaphragm or piston?

[SimonC]

Took mine to Star Performance in Kirkaldy last weekend. They diagnosed a faulty DV and replaced both with VAG ones. The improvement is subtle but definitely there, and no more whoosh!
What I can't believe, considering how many Audis are turbo-equipped, is that this fault has never been picked up by the main dealer who supplied (and therefore PDI'd) and on several occasions serviced the car. But they did also forget to reconnect the fog lights after changing the timing belt, didn't change my brake fluid on schedule and never did manage to cure the fault with my brakes. Would it be appropriate to name and shame for the benifit of others?
Sorry to go off on a tangent.
Car low on power? Main dealer maintained? Probably got a really obvious fault. Take it to a specialist. Or simply follow the advice of the people on here!

[lengster1]

Simon i think brake fluid change is additional to a standard service,but all the same they should check your cars history and ask you if you want it doing,my stealer wanted 95 quid but i really dont see that i need to pay 90 quid an hour labour for such a simple job

[Devil]

Normaly the brake fluid has to be changed every 2 years. Here in Belgium there aren't many specialist for these cars, the dealership ae mostely surprised to see one.

[S2tuner]

Devil, if you're in Belgium, send me a PM, I'll be over there next weekend and I can check your car out and see what's wrong with it!

Mihnea

[Golich]

Exhaust gas temp probes - perhaps

I was 80bhp down and didn't really notice it!! Well I knew there was something not quite right but only because the car stuttered/misfired on a long sustained climb after about 15 seconds of full throttle above 4500 rpm. It turned out to be a faulty exhaust gas temperature probe. There are two, one for each cylinder bank. It didn't always log a DTC and it didn't always misfire.

I would recommend having your car annually rolling road tested. For the same price as a stealer service I can have Jim at Star Performance service my car and perfrom a rolling road check. I used to do this with my chipped S4. But he's a 2hr drive from me and I've been lazy and giving it my local stealership Specialist cars in Aberdeen. They're quality of servicing is a real mixed bag. I'm sick to back teeth of them now and I'm probably going to do a mixture of service the car myself and take it to Jim for an annual rolling road and overall health check.

[TopBear]

.....and I'm probably going to do a mixture of service the car myself and take it to Jim for an annual rolling road and overall health check.

I'm booked in at the end of the month at Jim's place, and its funny as he mentioned whilst I was talking to him that there was an RS4 'on' his road as the car wasnt quite right.
I'm glad I keep reading good things about him

[Devil]

So, I replaced the DV's, didn't seem to help very much.
When you push the throttle like say 90% the car seems to go faster then when you push it 100%. What could this be?

I also have a fault code, Lamba , internal ressistance to high ( trying to translate i good as i can) This seems to have to do with the heating of the lamba sensor.
Does anyone have more info about this?

[simple1]

Try posting here.....http://rs246.com/index.php?name=PNphpBB ... forum&f=39
More chance of getting the specialised help you need.

[Devil]

I changend 2 Lambda sensors bank 1 and 2 before the cats this week.
The fault code is gone but still think that there is not enough power.
I don't know wath to do anymore.