For audi experts a very special misfire problem

[leverage454]

Hello
Im an audi master technician and im stuck with a misfire problem. Its an audi q5 2.0 tfsi 2010 , it has misfire in cylindre 1 at idle and when accelerating everything goes fine . I replaced spark plugs and cylinder 1 injector , coil ,
2 valve lift actuators for cylinder 1 , copression test gives 12 bars and thats ok , ecu replaced , wiring for coils and injectors testes and everything is in order , no shorcuts no resistance problems. I even took out the cylinder head for visual inspection and nothing wrong with it . Valves and camshaft are ok . I think i checked everything possible with misfire causes and nothing appers yet. I will appreciate your help so much . Ps : misfire is always and only in cylinder 1

[Andreastech81]

I am not an AUDI expert, i just read your post and thought to try to help you if i can

Is it a costant misfire at cyl 1 at idle ??
Did you done a cylinder drop test ??

Do you use scope ?? if so do a relative compression test to get direction for your engine health

Also scope your cam and crank sensor to be 100% that your signal is good, your flywheel clean, and the marks are spot on

[leverage454]

Hello yes its a constant misfire at cyl 1 at idle i did a cylinder drop test and that was ok . I didnt use scope yet , when engine is at idle i can hear a noise from flywheel but i thought even if flywheel is faulty it cant affect cyl 1 only. I guess i will re-assemble the engine and i will check signals from camshaft and cranckshaft.

[mastaflex]

does it make it only when warm or in all cases ?

[autoden]

Looks like a new dmf needed. If flywheel is wobbling sensor cannot read correctly, Autoden "not a master tech"

[racin-snake]

RE CHECK THE VALVE SPRINGS . common fault on FSI TFSI UNITS ..... as is inlet manifold gasket seals and cracks in manifold ( plastic manifolds )
Do you not have access to TECHNICAL SERVICE BULLETINS or guided test plans as a MASTER TECH ?

R.S also not a VAG mastertech

[leverage454]

Autoden ,im not sure if you know enought that kind of engines, so if so, if i unscrew the 3 three bolts that links the flywheel to the engine without taking the gearbox out the engine should runs ok ?

[leverage454]

Mastaflex,
Always warm and cold

[leverage454]

RE CHECK THE VALVE SPRINGS . common fault on FSI TFSI UNITS ..... as is inlet manifold gasket seals and cracks in manifold ( plastic manifolds )
Do you not have access to TECHNICAL SERVICE BULLETINS or guided test plans as a MASTER TECH ?

R.S also not a VAG mastertech

Yes i have full acces , but for valve springs i checked them and inlet manifold too . Both are ok

[racin-snake]

Post the vehicles engine code and fault codes present . we need to see what you see to help you .
Meanwhile swap no 1 injector to another cylinder see if fault follows .

[leverage454]

Post the vehicles engine code and fault codes present . we need to see what you see to help you .
Meanwhile swap no 1 injector to another cylinder see if fault follows .

Engine code is CDNC 2.0 tfsi
Fault code p0301 and nothing else
I replaced injector 1 and then i still have doubt on it and i swaped it with another injector and still same thing , and all injector seals are replaced

[racin-snake]

Have you tested for injector pulse and misfire counter ?

[joemajdalani]

Have you done smoke test to check for vacuum leaks around cylinder 1 ?