AAN problem. Ignition timing. Knock sensors...?

[Biggy]

UrS4 92. AAN. RS2 turbo, 7a cams, RS2 injectors, etc.. RS2 ECU, chipped.

The car was running ok for a year in this setup. For one and a half month the car wasnt driven at all.
Problems appeared suddenly. Sympthom is power loss after 4500-5000rpm.

ECU moves ignition later, after 4500rpm. Looks like knock sensors do their job.

VAG-tool and VAG-com dont show errors at all. Fuel pressure, pump, injectors, pressure regulator - ok. No boost leaks, no problems with sparks or ignition coils etc.. No problems with fuel or boost..

The only wierd thing i noticed is that if i disconnect one or both knock sensors - ECU doesnt store any fault codes, and there is no difference in car behavior with or without knock sensor(s). (Both sensors are new). I also double checked wires from Knock sensors to ECU.


Any ideas? Im trying to solve this problem for a month... Please help...

this is a screenshot of VAG-Tool, acceleration in 2nd gear.

Green is ignition
Purple is RPM
Yellow is lambda.
Blue is coolant temperature.




PS please excuse my bad english - i didnt have any practice for a couple of years..

[Biggy]

UP!

Anybody have any ideas?????

[Knight Rider S4]

Sure it is not a boost leak ......something gives way at high pressure level?....have pressure tested system?

[Jamo]

Timing?

Has the woodruff key broke on the cam shaft wheel? and are the cams correctly alligned?

[Biggy]

no boost leaks.

[Knight Rider S4]

is it total power loss at 4.5k or stuttering

[Biggy]

Timing?

Has the woodruff key broke on the cam shaft wheel? and are the cams correctly alligned?

no broken keys. timing is set correctly. cams alligned correctly.




some more logging from vagtool. 2nd gear run:

[Biggy]

and some more logging:

[Biggy]

is it total power loss at 4.5k or stuttering

it is power loss after 5-5,5k.. and a strange sound in exhaust, as if ignition was too late..

[Knight Rider S4]

The way it looks like you are going it to limp mode for the turbo which is giving you the loss of power ...have you had a boost gauge on when fault occurs to see how high it is running?

[Knight Rider S4]

Another thing have you cleaned the MAF to see if that helps

[Biggy]

The way it looks like you are going it to limp mode for the turbo which is giving you the loss of power ...have you had a boost gauge on when fault occurs to see how high it is running?

of course boost is falling a little bit, but not fast as acceleration...

and this strange sound in exaust...

[Biggy]

Another thing have you cleaned the MAF to see if that helps

yes i did. more then that - i tried 3 more different NEW adu and aan mafs. doesnt help at all.

[Knight Rider S4]

sound in exhaust will be unburnt fuel igniting maybe?....love Moscow by the way had a ball there last year was working in the Mariott Aurrora ...Shandra very nice club to go to!!

[Biggy]

i also changed knock sensors, crankshaft sensors, temperature sensor, lambda, intake air temperature sensor, ignition coils.....