04 Golf tdi BEW new VNT17 going into limp mode

Schnarsky

New member
Joined
Oct 5, 2019
Location
Keystone, CO
TDI
04 Golf BEW
Hey everyone, I’m new to the group but have been following you guys for awhile now.
My OEM turbo was leaking oil so I replaced it with a VNT17.
When I push the car i get great boost.
If I allow the car to be under around 2100 rpms and under some load, for example going up a hill in 5th at 60mph my car goes into limp mode.
It’s throwing a MAF sensor code as well as an underboost code these are new since the install of the vnt17
I also have a cam shaft sensor code that I have had for some time that I don’t think is part of the issue i only mention it because I don’t know what I don’t know.
I don’t think I have a boost leak, I haven’t deleted my egr, I still have the oem MAP (and really everything besides the VNT17)
I’m pretty stumped here and any info and advice would be greatly appreciated!
Thank you all very much
Schnarsky
 

Schnarsky

New member
Joined
Oct 5, 2019
Location
Keystone, CO
TDI
04 Golf BEW
The turbo is new. I don’t have a boost gauge but i had a mechanic hook it up to a computer to measure the boost he said it looked normal. I wanna say around 2100 millibars?
 

Yourbuddysatin

Veteran Member
Joined
Oct 28, 2016
Location
Pennsylvania
TDI
2013 Jetta tdi
I would check the vac procedure of the actuator to rule out the vanes arent sticking. Then move onto the n75 valve. Use a mighty vac and pull vacuum. 3hg is when the actuator will move the lever then around 17hg is where it will stop. Also check and make sure the lever will move smoothly.
 

PakProtector

Veteran Member
Joined
Jan 5, 2014
Location
AnnArbor, MI
TDI
Mk.4's and the Cummins
I would check the vac procedure of the actuator to rule out the vanes arent sticking. Then move onto the n75 valve. Use a mighty vac and pull vacuum. 3hg is when the actuator will move the lever then around 17hg is where it will stop. Also check and make sure the lever will move smoothly.
Second most of this. Looks like it is not pulling the vanes shut far enough to boost at low RPM...so as suggested, make sure the arm is adjusted so it starts pulling the vanes closed at 3".
cheers,
Douglas
 

Tdijarhead

Top Post Dawg
Joined
Nov 10, 2013
Location
Lawrenceville PA
TDI
2003 TDI Jetta Daughters Car, 2001 TDI Beetle, Wife’s car, 2005 Golf TDI Mine, all 5 spds
I was under the impression that to properly run a vnt17 you needed a tune?
 

Schnarsky

New member
Joined
Oct 5, 2019
Location
Keystone, CO
TDI
04 Golf BEW
Update:


I adjusted the VNT actuator rod. When I shortened the VNT actuator rod by 1 rotation I still went into limp during the underboost.

I then went 2 turns and got an overboost code.

I'm currently about 1.25 turns of the actuator rod shorter than I started, this has fixed the underboost issue and I'm not getting an overboost code but I am getting a troubling whining noise when I'm in 3rd gear and above at around 2900 rpms
 
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