need help! could it be my turbo or boost leak - wastegate issue

[bulak]

Hi peeps

Got a slight problem on my hands, remapped my car with bluefin handheld unit.

After driving straight out of my driveway just tapping the accelerator I notice a turbo sound, never heard it before never really heard the turbo before.

The car drives fine pulls like a train as far as I can tell, I called bluefin next day and told me it was normal as the turbo spools up quicker. So I decided to take the remap off thinking the sound should go away, but it didn't.

I been reading a lot on forums and people refer to it as the "owl" sound or "dentist drill" its faint but noticeable between 1300-2200rpm

I did a vagcom test no errors what's so ever but we did do a boost run while driving in 3rd gear till redline. From what we could make out it was under boosting slightly.

My question is should I be worried? and has anyone come across this as a easy fix i.e not the turbo.

[bacillus]

Any chance of posting the boost log?

[sub39h]

which engine? age? mileage? other mods?

might be a failed DV if you've not replaced it for a Rev D

[bulak]

Any chance of posting the boost log?

No I don't have the log was on my mates laptop, see if I can get it

[bulak]

which engine? age? mileage? other mods?

might be a failed DV if you've not replaced it for a Rev D

mk5 gti dsg 2005

56k on the clock checked engine oil and the level is fine

i have full blueflame turbo back exhaust and dbilas cold intake

had a new DV put in about 6k ago sure its the Rev D bought from awesome GTI

[PDT]

I can't really help with your problem, however this is one of the reasons that using a tuning company to professionally tune and set up the car rather than using a 1 size fits all map from a handheld unit has its advantages.

[RedRobin]

.
When I read the thread title I thought I may be able to help because I had a boost leak on my Mk5 DSG 05-plate 06-build K03 and wrote a thread in Troubleshooting I could have linked you to, but, what PDT said:

I can't really help with your problem, however this is one of the reasons that using a tuning company to professionally tune and set up the car rather than using a 1 size fits all map from a handheld unit has its advantages.

[jason_rmh]

I have a similar issue with the owl noise at low revs.
What is the best way to log Turbo data using vcds.
Eg. Do you have to drive in a certain gear / rev range and which values are best to log?

Edit: just done a search and found some good info here:
http://www.mk5golfgti.co.uk/forum/index.php?topic=17636.0
Thanks

[john87]

It sounds to me like your diverter valve is staying open at lower revs, as when I had my TWINtake fitted, you can hear the 'owl sound' when you partially lift off after accelerating, and it dies away after 2-3 seconds.

[RedRobin]

.
So, if I understand the topic correctly, it's help with sound rather than performance that's being asked for?

Personally I love all the sounds which I hear from the engine bay and especially those from my Twintake after a fast lift off the throttle. I like that 'whipping' sound.

[bulak]

It sounds to me like your diverter valve is staying open at lower revs, as when I had my TWINtake fitted, you can hear the 'owl sound' when you partially lift off after accelerating, and it dies away after 2-3 seconds.

I have try to pinpoint the sound and it is come behind the intake which connects to the turbo, I took it one mechanic yesterday I don't think he knew much to be honest but said its turbulance with the air coming In and turbo spinning that fast.

A friend of mine has similar mods to mine and he's got no sounds
Decat turbo back, dms stage 1, itg intake.

[robdf2]

i thought the "owl" noise was specific to diesel engine?

[bulak]

So I had a conversation with bluefin yesterday and they asked me to do some checks on vag-com for the following

Boost pressure
Fuel pressure
Ignition timing

In 4th gear from 1500rpm to redline. Got a email back this morning


 Good morning.

The data you have supplied for the fuel system shows that the in tank pump is getting very close to maximum capacity. We'd expect to see a pretty much solid 5bar (5000mbar on VCDS) across the rev range with a healthy pump. We would also like to see similar logs of the high pressure fuel rail data. Normally the values will be around 110-120bar at full throttle and you should have desired & actual figures for this parameter.

The other interesting data is the boost pressures. Your car seems to be struggling to keep the boost down to the desired levels between 2000 and 4000rpm where as the boost is below the requested values above 5000rpm. Further logs showing the waste gate duty cycle & N75 valve duty cycle may be helpful here but there may be a warn or faulty component within the boost control circuit that may need repairing or replacing. It would be worthwhile to get the waste gate actuator checked for a leak and to double check the plumbing for the boost control system.

Kind Regards, Michael Howard.

Anyone come across this problem with the wastegate and how to go about it, I was thinking to call awesome gti as I live in Manchester but I know they can be expensive.