1.6FSI BAD, inner manifold flaps stuck

[Anelkka]

Hello everyone!

 

I bought second A2 for me as a project. It is with FSI engine and it had some coolant leaks and manifold flaps were cooked from carbon debris.

 

Coolant leaks are now sorted and manifold flaps cleaned. Problem with manifold flaps are still on going. When I did clean the flaps, they were moving nicely and free. After putting everything back together, starting car and successfully done adaptation via VCDS from group 142 everything seems to OK but not really. Couple throttle revs and I found out that flaps are stuck again. I did undo vacuum hose from actuator and actuator arm is completely stuck. 

 

Any ideas what could be the reason before I will dismantle again?

[Lupo_3L]

I'm afraid I cannot ontricute to resolve the stuck flaps, but I can warmly recommend the software from Pro Boost which deactivates the pflaps, resolves also other FSI relate issues and improves driveability signifficantly. It will also deactivate EGR which keeps the injector nozzles clean.

https://proboost.shop/produkte/software-update-audi-a2-1-6fsi/

[Anelkka]

Thanks for reply. I prefer to keep everything original so far. I will dismantle everything with thought maybe in couple weeks and I will update situation after that.

[Krebserl]

I had this same problem a couple of weeks ago with my FSi. The flaps were stuck after a few hours of run time. The problem made me crazy because I dismantled the flaps 3 times until I realized the root cause. The horizontal clearance of the shaft where the flaps are bolted on was obviously too much. When the engine reached its operating temperature the flaps got stuck. After cooling down they didn’t move either so I removed the manifold, checked everything to be moving easily … until they got stuck again. After the 2nd dismanteling I investigated further and could reproduce the problem by hand. When pressing the shaft where the flaps are bolted onto to either side they got stuck. I could see marks from the flaps on the inner wall of the manifold.

So finally I replaced the whole lower manifold.

Rework may be possible by unbolting the flaps from the shaft and removing appprox. 0.5mm on each side of each flap to give it more clearance to the manifold wall. Reducing clearance of the shaft maybe possible with some shims…?
I didn’t take the effort to try it… but I’m sure it can be fixed to save the cost for a spare part.

 

[LiebesKugel69]

vor 14 Stunden schrieb Lupo_3L:

I'm afraid I cannot ontricute to resolve the stuck flaps, but I can warmly recommend the software from Pro Boost which deactivates the pflaps, resolves also other FSI relate issues and improves driveability signifficantly. It will also deactivate EGR which keeps the injector nozzles clean.

https://proboost.shop/produkte/software-update-audi-a2-1-6fsi/

Kann man eigentlich mit der ProBoost Software dann auch die "Drallklappen" komplett im ganzen ausbauen? Diese sind mechanisch Defekt bei mir und Ersatz gibt es ja leider nicht mehr... 

[Lupo_3L]

vor 3 Minuten schrieb LiebesKugel69:

Kann man eigentlich mit der ProBoost Software dann auch die "Drallklappen" komplett im ganzen ausbauen? Diese sind mechanisch Defekt bei mir und Ersatz gibt es ja leider nicht mehr... 

puh, das kann ich nicht beurteilen, denke aber schon. 
Ursprünglich funktioniert der FSI als Schichtlader wo der Kraftstoff in ein Orbital des Kolbens um die Zündkerze eingespritzt wird. Dieser Schichtladebetrieb wird mit Pro Boost ja eigentlich deaktiviert, also sollten die Klappen keine Funktion mehr haben. 
 

Grok meint:

 

Das ist eine gängige Modifikation bei FSI-Motoren (z. B. 1.6 FSI in Golf, Passat oder Audi A3), um Bruchrisiken zu eliminieren, den Ansaugtrakt zu reinigen und den Luftdurchfluss zu optimieren. Die Software-Deaktivierung (wie ProBoost oder VCDS-Codierung) schaltet die elektronische/magnetische Steuerung der Klappen ab, sodass sie nicht mehr aktiviert werden – aber sie sitzen physisch noch im Saugrohr und können festsetzen oder brechen. Das Ausbauen ist danach unkompliziert und sogar empfehlenswert, da es den Trakt freimacht.

Warum ausbauen, auch nach Deaktivierung?

• Vorteile: Besserer Volumenstrom (bis zu 5–10 % mehr Leistung bei höheren Drehzahlen), keine Verkokung mehr, leichteres Reinigen. Viele Tuner berichten von spürbarer Agilität.
• Nachteile: Leichter Leistungsabfall bei sehr niedrigen Drehzahlen (unter 2.000 U/min), aber das wird durch die Software-Optimierung (z. B. angepasste Zündkarten bei ProBoost) ausgeglichen. Im Alltag merkst du das kaum.
• Rechtlich/TÜV: In Deutschland ist das erlaubt, solange die Abgaswerte passen (kein Leistungsplus über 30 %). Lass es vom TÜV abstempeln, wenn du unsicher bist – oft als "Optimierung" akzeptiert.

Ich persönlich habe nach Proboost Optimierung einen deutlichen Drehmoment Zuwachs im unteren Bereich gespürt. 
Fährt sich wie ein anderer Motor. 

[Anelkka]

vor 37 Minuten schrieb Krebserl:

I had this same problem a couple of weeks ago with my FSi. The flaps were stuck after a few hours of run time. The problem made me crazy because I dismantled the flaps 3 times until I realized the root cause. The horizontal clearance of the shaft where the flaps are bolted on was obviously too much. When the engine reached its operating temperature the flaps got stuck. After cooling down they didn't move either so I removed the manifold, checked everything to be moved easily … until they got stuck again. After the 2nd dismantling I further investigated and could reproduce the problem by hand. When pressing the shaft where the flaps are bolted onto either side they got stuck. I could see marks from the flaps on the inner wall of the manifold.

So finally I replaced the whole lower manifold.

Rework may be possible by unbolting the flaps from the shaft and removing approx. 0.5mm on each side of each flap to give it more clearance to the manifold wall. Reducing clearance of the shaft maybe possible with some shims…?
I didn't take the effort to try it… but I'm sure it can be fixed to save the cost for a spare part.

 

Actually I discovered this same thing when manifold was at table. Good idea about grinding flaps little bit, I will sort out this one. Thank you for replying