mystery continues ;)

[kwlw]

Hi,

After long months of desperate fight with electrical gremlins in my ersatz urq project wiring loom, and burning to near-death state three ecu's, I finally managed to start the engine . "New" ecu, is from S4 AAN with automatic gearbox. After heating the engine, I've did some test runs on the snow. It revs up like before , pulls like before. Cannot test boost level on the snow (0.2bar and it looses traction) but it seems ok.

BUT! Revlimiter is on 6500-6700rpm range (was in 7000-7200 with ABY ecu),
also engine is refusing to drop rpms in sports car style, when throttle is closed rapidly. It drops revs smoothly like KE-Jetronic based KV engine .

Also this ecu is not responding to the K-Line for some reason (VAG-COM).

Should it behave like that ?

Sau
P.S. VAG P/N 4a0 907 551 B still havent opened it to check with firmware version i is in it .

[kwlw]

One more mistery is solved .

Found that K-Line connection was loose .

Also there are the results of AAN engine in typ85 behaviour with stock ecu's:

4A0907551D (S6, automatic) car is not starting, ECU is locked my immobilizer
same box with some weird 4a0907551AA software. ECU is not locked, no errors, car not starting, because there are no ignition pulses to the coils (distributor needed ?)

4A0907551B (S4, automatic). Car starts, runs fine, however engine revs are dropping slowly. Also this ECU gives more boost at the start (up to 0.4 bar) before releasing the clutch. Rev limit is at 6600rpm, fuel cut is not pleasant, I can call it even rude.

895907551B (S2 ABY). Car starts, runs fine, revs are dropping sporty style. Gives only 0.2 bar boost at the start. Fuel cut is at 7100-7200 rpm range, not annoying or disturbing.

4A0907551AA (S4, Techtronics tuning chip inside). Car starts, runs very smooth at idle. Revs are rising and dropping faster that with automatic, but slower than ABY. At the start you can rise boost up to 0.5 bar. Fuel cut is at 6900-7000 rpm range.
I am a bit afraid of this setup , because, on slippery ice it managed to get 0.7 bar (3 gear, 100kmh at speedo, 1-2kmh real). Ecu's mentioned above did only 0.2-0.5 bar in these conditions.

Waiting for spring to come, and the temperature to rise.
Then I can make front of my car, and hit the streets and the race track .

Sau

[Stick Insect]

You have done a lot of work on your car, I hope you get it running right.

A lot of the technical people are off at a meeting today (wish I was there)

They may be able to help more than I can.

Keep up the good work.

David

[S2central.net]

The 895907551A or B is really what you need. 'B' actually expects immo but can be worked around. Your low boost problem (assuming all ECU wiring is correct) is maybe due to an air leak or a mistake on the plumbing.

Stick with these chips for now - collect any fault codes and run output tests with OBD plugs or VAGCOM if you have it.


Paul

[kwlw]

The 895907551A or B is really what you need. 'B' actually expects immo but can be worked around. Your low boost problem (assuming all ECU wiring is correct) is maybe due to an air leak or a mistake on the plumbing.
Stick with these chips for now - collect any fault codes and run output tests with OBD plugs or VAGCOM if you have it.
Paul

Thank's again for info. Sorry for confusing you. These tests are made in the backyard. My car is street illegal at the moment (no lights, no front bumper, etc.), so I can drive it only on short strip in the backyard, first or second gear . Now this strip is covered with ice, and the car has summer tires, thus no load for turbo to make a boost. There is no ecu errors, and the plumbing seems to be ok.

I just wanted to say, how much powerfull is engine mapping setting. Same car, same engine, same final HP/Nm output, only different setup. And the car behaves absolutelly different with different ECU software. It's amazing .

BTW what is mistake in plumbing ? Could you be more specific, maybe I have some.

Sau

[jameswkr]

Sau, I think Paul is referring to the orientation of both the WGFV and the TBV. Both can be connected wrongly and reduce boost and/or lead to "odd" running behaviour. WGFV should have longest horizontal pipe going to MAF/ Turbo infeed, shorter horizontal pipe to WG and vertical pipe to turbo outfeed. TBV "standard" is with turbo outfeed hitting the valve movement from the side. Other things to check :- Throttle switch, base throttle setting, cable slack. Keep us posted. James.

[kwlw]

Sau, I think Paul is referring to the orientation of both the WGFV and the TBV. Both can be connected wrongly and reduce boost and/or lead to "odd" running behaviour. WGFV should have longest horizontal pipe going to MAF/ Turbo infeed, shorter horizontal pipe to WG and vertical pipe to turbo outfeed. TBV "standard" is with turbo outfeed hitting the valve movement from the side. Other things to check :- Throttle switch, base throttle setting, cable slack. Keep us posted. James.

I have load's of documentation, including VAG service books . WGFV is connected properly, however I've intentionally connected recirculating valve (TBV) for boost to hit from "below".
As I suppose it should not have side effects on boost , but instead will make TBV operation faster. I'm using bigger aftermarked TBV which has very stiff spring, as far I understand it is influenced only by pressure drop in IC and intake manifold. So there should be no issues, unless I will blow "signal" hose. Then I will have big boost leak .

Sau

[jameswkr]

Fair enough. I have also run with Dialynx TBV in reverse with some driveability issues. Sorry, cannot suggest any further ideas. James.