[Legendary7801]

Greetings from Turkey. I have a Golf4 1.9 TDI 90hp Agr engine. There is a whistling sound from the turbo at 1100-1200 rpm. This is how I get a pressure graph when I watch it on the computer with Vcds. Do you think I need a new turbo by looking at this chart or is everything normal?

 

[gerrywac]

A mild turbo whistle from a 1.9Tdi when accelerating from idle is a characteristic of the mk4/5 Golfs fitted with various 1.9 turbo engines.
I've an 2007 MK5 1.9Tdi that I bought in 2010 and I learned about the whistle when I read up about what to look for when buying.
Sure enough it was there in the background when I drove it.
I bought the car and 11 years and 45k miles later its going strong with the same unchanged whistle.

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[TGDTDI]

I've had the same experience as Gerrywac,both on mk4s and mk5s.My friend has a mk5 1.9 that he thought had a defect turbo because of the whistle.Fitted a used one from a breaker with 60.000 miles on it,that was exactly the same.Sadly the car got rear ended on the way home from the garage...
Looking at your video i'd say you boost is too low compared to what is requested,i'd look for boost leaks,if none then maybe the vnt needs adjusting.This is just my guess,i'm sure someone a bit more knowledgeable will come along soon.

 

[Legendary7801]

My acceleration video:

Do you think these values are normal?

 

[gerrywac]

I've had the same experience as Gerrywac,both on mk4s and mk5s.My friend has a mk5 1.9 that he thought had a defect turbo because of the whistle.Fitted a used one from a breaker with 60.000 miles on it,that was exactly the same.Sadly the car got rear ended on the way home from the garage...
Looking at your video i'd say you boost is too low compared to what is requested,i'd look for boost leaks,if none then maybe the vnt needs adjusting.This is just my guess,i'm sure someone a bit more knowledgeable will come along soon.

It is, quite possible that boost leaks might doen grade performance over time without being serious enough to trigger a fault code.
Several years ago I would get intemittent MAF codes on my MK5 1.9Tdi (105PS BXE) but when I checked them in VCDS boost actual/demand there was no issue and it would clear upon restart before eventually returning. This went on for 18 months until one day I had a total boost failure due to a failed boost pipe connect OSF to the bottom of the intercooler. It was apparent on inspection that the retaining ears had wotn very badly on the retaining clip and just let go.
When a repair was done I noticed tbat the acceleration and mpg was somehat improved and the internittent maf fault never returned.
I concluded that wear had allowed intermittent movement overcoming the seals and allowing a slight boost loss, degrading acceleration a little and causing the odd fault code.

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