tdi 110bhp, turbo not kicking in, max speed 80!

hi

have got a 99 mk4 golf tdi (ahf engine, 110bhp) but is lacking on power.

the top speed it hits is around 80 (takes forever to get to that!) but generally after about 55 anything like that is hard work.

it feels to me like the turbo is not kicking in at all as u get to just over the 2000rpm mark and it then feels as though it is about to but suddenly hits a flat spot and then after that no response from the turbo. it literally feels like driving the non-turbo 1.9 diesel engine.

there is no problem with the turbo itself as it has just been reconned and a vagcom shows up no errors.

any thoughts anyone?

cheers

 

Sounds like you have a vac/boost line split or come off or you`re N75 valve is kaput (though VAGCOM should show that).

Here`s a diagram so you can check all the necessary lines (courtesy of TDIClub);

 

i have exactly the same issue with a 01 plate golf tdi flat out 80 mph

 

check all the vacuum lines, primary the line that goes on the turbo diapham, it should such & the little arm it controls moves freely on and off with vacuum

 

Try the above first,

Turned out to be a stuck VNT mechanism on mine, I know you said it's been 're-conned' but that doesn't mean it works! Doesn't take long to get clogged with carbon.

see if the linkage moves freely by hand, if not then you can sort by a) removing turbo and cleaning or b) mr muscle trick

Vagcom should have errors though if its not achieving it's target boost? mine was stuck closed so it was over-boosting and going into limp home.

 

Could be a dodgy MAF sensor...

 

well had a play

found a vac hose from the boost control valve that had worn the out sheath away rubbing against another pipe although it wasnt split i think it was being sucked flat so hoping thats the fault found

the little arm on the round silver thingy lol moves fine ive got a code reader coming tommorow so will check for any errors i think the car may have gone into limp mode when i tried to boot it in 3rd gear joining the motorway

also unplugged the maf and it made it worse so not that

 

plugged in a code reader and it came back with no error codes so hoping ive solved the issue

 

its entering in safe mode, common issue, VNT mechanism clogged. been there done that. open the turbo and clean the geometry mechanism... or flush some wd40 on the exhaust outlet til it drips out...not the correct way tough...