Hi @all

I drive an S3 1.8T from 1999.

It has an Narrowband ECU without VVT and EGT Sensor from factory.
ECU Number is: 8L0906018N

I have done some mods to it for example:
K04 turbo with 47mm compressor and 44 mm turbine
H-rods, Sachs Race clutch, 2,75mm exhaust from turbo
Bosch 470cc injectors, 4bar FPR and DW65V fuel pump

From the beginning I have the problem, that the system leans out when boost goes over 1,3 bar.
I have installed a wideband Lambda gauge for diagnostics...

1,0 bar - 0,80
1,1 bar - 0,80
1,2 bar - 0,80
1,3 bar - 0,83
1,4 bar - 0,88
1,5 bar - 0,91

Software on the ECU is made by a guy with skills (also on the Nef Forum)

I have already replaced my fuelpump 3x times
- MAP and MAF sensor
- my FPR and my injectors even with bigger ones like deka 630 but the problem was still there :-(

Is this a narrowband problem ?

If yes, than I want to swap the ECU to wideband model like 06A906032 HN
Because it has no egt sensors like an S3 wideband ECU

So my plan is to swap a Golf 4 1.8t wideband ECU into my S3, replace the O2 Sensor and deactivate VVT in the file of 032 hn

Does someone have a complete pinout of both ECUs ?

Thanks in advance for your help.

Oliver

i agree. narrowband isnt ideal but it should still technically work.

Who is your tuner?  Why 4 bar?  DW65V should be plenty; you have an issue somewhere else.

I checked the fuel pressure under full load.

With 1,5 bar of boost and 4 bar FPR, the pressure is 5,5 bar from 3000 - 6000 rpm.


So this is not my problem 

Topic author wrote:

I double checked my complete Boost and Inlet pipes.
Everything is ok and has no leaks.

There is another strange thing I want to tell you.

When I reset all learning values with VCDS on the ECU it will always run on Lambda 1,0

No matter how much I press the gas pedal on any rpm or boost it will alway stay on Lambda 1,0

I already replaced the O2 Sensor.

The only way to get the car run richer is to use Lemmiwinks and set primary fuel to +25%
But this is very unprecise as you can imagine.
Sometimes the car runs rich like 0.80 under WOT. After 10 seconds waiting for the next WOT pull it runs lean like 0.93 under full load.


My LAMAFA and KFLBTS maps request a rich mixture like 0.78 so that should not be the Problem

 

I dont know what to do anymore but swapping to a wideband :-(

No fault codes are stored on the ecu.

OK

Then let us start with logs.

I have VCDS. What do you want me to log ?
I guess rpm vs lambda.
Boost ?

Fuel pressure is defenetly ok.

My guess would be, that my ECU is faulty