RS246.com Forum :: The World's #1 Audi R, S and RS Enthusiast Community

I just bought a 2001 RS4 and It did not feel faster than my E36 3.2 M3 so I took it to the dyno.

It made only 352hp and 449nm. The car has remap and exhaust with decat. It has 228000km.

What are the possible causes of lack of power? I was expecting something around 400hp.

The timing belt service will be done shortly. What to look for?

Where does one start?
EGT(s)
MAF

Do a Vag Com scan and post the results.
If there are no codes, do a live data run with VCDS logging MAF and post here

There are too many fault codes that we have detected.

16524 Oxygen Sensor B1 S2

P0140-35-10- No activity-ıntermittent

17861- Exhaust Gas Temp Sensor 1 (G235)

P1453-35-10- Open or Short to plus- intermittent

17521-Oxygen Sensor; B1 S1

P1113-35-10 -İnternal resşstance too high- intermittent

17547 Fuel Trim: Bank 2 ( Add )

P1139 -35-00 System too rich

17545 Fuel Trim: Bank 1 ( Add )

P1137-35-00 System too rich

17537 Fuel Trim, Bank 2 ( Mult )

P1129-35-00 System too rich

Looks like replacement EGTs and a Maf as well as the Cambelt service! Have the lambdas ever been changed?

I will try to change them as soon as possible.

I have no clue ıf lambda sensors have been changed or not...

Definitely EGTs, a fault with those will reduce boost
Lambda faults don't tend to reduce power in the short term

neckarsulm wrote:Definitely EGTs, a fault with those will reduce boost
Lambda faults don't tend to reduce power in the short term

Thanks for the info. Do I need to replace both of them.....It seems that one of it is faulty??

Those things are really expensive

JJ-RS4 wrote: Those things are really expensive

Welcome to RS ownership.

you can replace just the faulty one (unlike turbos)

Amar wrote:

JJ-RS4 wrote: Those things are really expensive

Welcome to RS ownership.

neckarsulm wrote:you can replace just the faulty one (unlike turbos)

Hi,

One of my friend will come from Germany this month. I will order the EGT repair kit and MAF. As he will bring the parts, I will ask him to get another things....for example: Set of spark plugs? Anything else?

MAF-EGTs and spark plugs were changed by new ones....fuel trim and EGT fault codes were all been cleared. The vehicle seems to operate better than before as well as less fuel consumption. But we have a new problem.....when the engine is on boost about 5000rpm, It sometimes feels sluggish and cuts power suddenly....the car behaves like a NA 2.0 rather than 2.7T.

We took the car to the mechanic where the parts were installed and diagnosed it. Fault codes are right below. The car has decat.


16815/P0431/001073 - Warm Up Catalyst; Bank 2: Efficiency Below Threshold

17521/P1113 - Oxygen (Lambda) Sensor; B1 S1: Internal Resistance too High

I am not sure these faults are really effective on performance cut, the car has decatted as I mentioned.

This is the last fault code and most suspicious !!!!

17964/P1556 - Charge Pressure Control: Negative Deviation

As I searched for the fault code, I got some info from the net.

Possible Symptoms
Reduced power output
Limp mode
Possible Causes
Boost Pressure too Low
Hoses/Pipes incorrect connected, disconnected or leaking
Charger Pressure Control defective
VNT (variable nozzle turbo): nozzles stuck
Solenoid Valve for Boost Pressure Control (N75) defective
Possible Solutions
Check Hoses/Pipes to/between Components
Check Solenoid Valve for Boost Pressure Control (N75)
Check / Clean / Replace Charge Pressure Control
Check / Clean mechanism for variable nozzle

Has anyone faced with the same problem? What to look for initially? Leaks or N75?

Thanks for your help

N75 valve... Had same prob and dough changed it and it was fine... Is the n75 also know as boost pressure sensor?