Turbo problems with no error codes

[theOctopus]

Hi Everyone

I have been having problems with my turbo for a few weeks now and I'm in the process of trying to get it sorted, I'll list the problem and I'll list what Ive done and are about to do, but if anyone has had similar problems please let me know.

PROBLEM:

No error codes showing VCDS (Vag-com had Lucas scan the car on Monday).
Lost boost Ive gone from 16-17 PSI to 8-13 PSI and that's if I'm lucky.
Lots of Turbo lag, hard to hear it spool up anymore.

FIXES so far:
Installed new APR R1 diverter valve.
New NKG spark plugs.
Replaced vacuum hoses from the FPR (Did this with a boost gauge install before I had the problem that's why I know I've lost boost).
Have a new N75 J revision valve to install tonight.

Note the car is chipped by GIAC and was running great for months.

Also I have just had the middle muffler removed and had a Remus muffler installed, but I've been told by a few people that this is not related and it was just a coincidence the turbo started playing up after I had this done.

At the moment it drives like crap and it pisses me off every time i get in it, When I chipped it it felt amazing and I grinned whenever I drove it, I just want that feeling again.

Any help or ideas would be great, and If anyone has had the same problem if you could let me know what you had to do to fix it that would be great.

Please helpppppp

[WhO]

Just a stab i the dark, Not exactly sure how the standard wastegate setup is but i'd assume its an internal gate with an external vacuum actuator. See if you can find it and see if it's plumbed up ie no hoses split or popped off etc

[noone]

Not sure if the MAF will throw a code, but could be an issue. Apparently disconnecting the MAF will get normal boost back (not a solution, but could show the MAF is the issue).

[theOctopus]

Ill Replace the N75 tonight if that doesn't fix it then I'll look at the MAF, but removing it and driving will throw a code for sure haha.

Does anyone else recommend testing the MAF this way?

Also I'll look at the test WhO noted, just need to figure out how to do it for my setup.

[theOctopus]

Ok been for a very long drive haha.

I changed over the n75j I just got with the old one which was a n75f.

Also checked the MAF and it and the housing are really clean no oil etc.

Ok after resetting the ecu (battery) waiting for the TB to calibrate I took it for a spin easy at first then I pushed it, in terms of the Turbo itself it sounds like it use to before the problem and I think the new n75 has really smoothed it out I'm now getting a stable 15psi which is way better than before but still has a lot of lag.

I can deal with 15 for awhile until i can do a boost leak test then Ill get all new hoses and ill replace and do another boost leak test, when you think about it the hoses are 10 years old if they are not failing now they will sometime so new hoses all round need to be done.

But if anyone has heard about things that can cause this without throwing codes let me know, its going to be awhile for the hoses and test.

In my searching I've found it can be caused by almost anything so any more help would be great.

[theOctopus]

Still been having problems with this, and i think i maybe on the right track.

Pcv and/or fpr

I noticed a big drop of vac on the weekend down to about 18 at idle was about 22 (hg), so replaced all the small vac hoses from the manifold and fpr then noticed this (see pic)




Just above the rectangular shape on the hose is a large split, I've tempory used some high pressure silicone tape to cover it till i replace it. Vac came back to 20 but after further playing and listening i can hear air coming from the fpr.

What would i do to fix a leak from the fpr??

Also what should the normal vac readings should be??

[leighaus]

22 is about bang on for vac mate. where on the FPR is it leaking?

[theOctopus]

22 is about bang on for vac mate. where on the FPR is it leaking?

The edge where is sits in the fuel rail (sorry i think that's how to explain it)

[theOctopus]

Need advice again guys got a strange sound which sounds like it's coming from the turbo, at around or above 16 psi I can hear a squeal a bit like a bad ac or power steering belt. It's not the normal turbo spool sound

I have just installed a 3 inch downpipe and now it's spooling up faster I hit 16psi early and it wants to go further but with the noise its making reluctant too.

This maybe related to the existing problem of the boost dropping to 15psi from around 20psi and now the downpipe let's it spool faster its noticeable.

What could it be??

I'm now at the point of getting it looked at but would need to be recommended someone to go to who knows their stuff with these cars in melbourne?

Sent from my GT-I9100

[Ironman]

Possible the bearings have gone in the turbo.... causing the squeal. I'm not a mechanic but they are 1 of the 2 moving parts inside a Turbo. either that or your turbo has become unbalanced and is grazing the inner wall. I could be wrong however