1.8T loosing power

A mate is having probelms with his 1.8T Mk4. It has lost a lot of its power.
He had a local garage do a diagnostic check and the turbo is producing about 7.5bar boost. The only fault was a slightly high voltage reading on the lambda sensor. He has replaced the air mass sensor recently and the boost release valve. The car is completely standard and was serviced recently.

Any ideas? I know bugger all about these new fangled engines.

 

look here:
http://www.uk-mkvs.net/forum/forum.asp?FORUM_ID=5

 

108psi!!!!

i bet that's got some lag on it!
Edited by: wez.mk3

 

Alright. He never said he had done that.

 

maybe worth running it up on a dyno to find out what happening?

 

if you mean 71/2 bar thats standard boost on a 150bhp model running k03 / k03s

older lamda's are a bit hit and miss, especially the post cat one which can cause you all sort of problems.

any smoke?

also check the dv's not split its diaphragm (if its standard) and also all the boost pipes are tight.

 

I think you will find its 7.5psi not 7.5bar (110psi)

edit: try a compression test?
Edited by: Rallye

 

He did mention 110psi which is why I converted it to bar.

 

if the turbo is making 110psi then im extremely impressed, and his car will be flying.

More than likely they did a compression test and they said that the cylinders are holding 110psi
Edited by: Rallye

 

indeed, my bad

 

A weak point on these engines is the crappy plastic dump valve.these leak then loose boost so need replacing with a nice alloy 1! A standard 1.8t makes about 5psi boost pressure,it would be nice to think an engine could hold itself together at 110psi of boost