Hissing sound

[acebundi]

Hi All

I have a audi a4 2005 s-line 2.0 tdi 140bhp the car has been juddering ever since I bought it 6 months ago between 1500 -2000 revs and has gone into linp mode when I go into 6 gear I have been trying to resolve this issue but just today I have notice a hissing sound under acceleration? im not sure if this is related to the previous issues but I will be checking the actuators tomorrow but any other tips would be much appreciated

[frankc]

Hissing sound is very probably a boost pressure leak. Check all the hoses from the turbo through the intercooler to the inlet manifold.

Take your time to check all hose clips are properly tightened and note that even a slight split or crack could lead to significant boost loss.

Also a good indicator of leak location could be a slightly oily black residue on surrounding parts.

Potentially a boost leak could lead to limp mode as the ECU notes a difference in measured boost delivered compared to boost expected.

Good luck, Frank

[acebundi]

Hissing sound is very probably a boost pressure leak. Check all the hoses from the turbo through the intercooler to the inlet manifold.

Take your time to check all hose clips are properly tightened and note that even a slight split or crack could lead to significant boost loss.

Also a good indicator of leak location could be a slightly oily black residue on surrounding parts.

Potentially a boost leak could lead to limp mode as the ECU notes a difference in measured boost delivered compared to boost expected.

Good luck, Frank

Thank you very very much

[manix]

I have a similar issue on my 2003 A3 8P 2.0TDI sport. The car hisses under acceleration and idling is a bit rough. Also rough on decelleration. EML has come on and suggests MAF sensor issue (16485 - Mass Air Flow Sensor (G70): Implausible Signal). I've changed the MAF sensor, the air filter and checked pre-MAF for any blockages or leaks but it is all OK. I guess the next is to look post-MAF and at the intercooler and turbo pipes.

Genarlly the cars performance is still OK, it starts every time, perhaps a little splutterly and accelerates pretty well. Only had the car since feb, so maybe I've only felt half the power! If I fix this and it's more rapid, i'll be well chuffed, and will certainly be leaving my mates 3 series TD behind!

I'll post here any solutions I eventually find.

[Beany1]

I have a similar issue on my 2003 A3 8P 2.0TDI sport. The car hisses under acceleration and idling is a bit rough. Also rough on decelleration. EML has come on and suggests MAF sensor issue (16485 - Mass Air Flow Sensor (G70): Implausible Signal). I've changed the MAF sensor, the air filter and checked pre-MAF for any blockages or leaks but it is all OK. I guess the next is to look post-MAF and at the intercooler and turbo pipes.

Genarlly the cars performance is still OK, it starts every time, perhaps a little splutterly and accelerates pretty well. Only had the car since feb, so maybe I've only felt half the power! If I fix this and it's more rapid, i'll be well chuffed, and will certainly be leaving my mates 3 series TD behind!

I'll post here any solutions I eventually find.

Did you find a fix thanks

[Crasher]

Hope so, it was 13 years ago…