Another Turbo question?

GeneralDisorder

Hey Guys, I'm looking to tap into some of that legendary motors forum knowledge.

Had an issue for the past few months where my car (2005 vw golf 2.0l TDI) would enter limp home mode due to an overboost fault (had the codes read at the time). Cycling the car from on - off - on again always cleared the issue so it was believed at the time not to be a mechanical issue with the turbo.

I got the car in to be looked at and the n75 boost control solenoid was replaced, this was believed to be the root cause, and not a leaking vacuum hose or an issue with the VNT actuator for the turbo.

The issue is still occurring so the car has to go back in to be looked at, but before it does i was hoping ye might be able to answer a question for me.

Is the VNT actuator for the turbo a separate part to the N75 solenoid, or would replacing the n75 solenoid mean that this was also replaced.

The 3 areas i'm going to get them to take a look at are:

1) Leaks etc... on vacuum hoses to the turbo
2) Damaged/Sticking VNT actuator due to holes or soot build up
3) MAF sensor issues

Is there anything else I should look at also? I'm just hoping its not an issue with vanes sticking internally in the turbo itself.

Thanks for your help.
GD

George Dalton

The VNT is the vane mechanism in the turbo itself.

MAP sensor and MAP sensor wiring should also be checked. They are common problems on the Mk5.

MrFrisp

GeneralDisorder wrote: »

Hey Guys, I'm looking to tap into some of that legendary motors forum knowledge.

Had an issue for the past few months where my car (2005 vw golf 2.0l TDI) would enter limp home mode due to an overboost fault (had the codes read at the time). Cycling the car from on - off - on again always cleared the issue so it was believed at the time not to be a mechanical issue with the turbo.

I got the car in to be looked at and the n75 boost control solenoid was replaced, this was believed to be the root cause, and not a leaking vacuum hose or an issue with the VNT actuator for the turbo.

The issue is still occurring so the car has to go back in to be looked at, but before it does i was hoping ye might be able to answer a question for me.

Is the VNT actuator for the turbo a separate part to the N75 solenoid, or would replacing the n75 solenoid mean that this was also replaced.

The 3 areas i'm going to get them to take a look at are:

1) Leaks etc... on vacuum hoses to the turbo
2) Damaged/Sticking VNT actuator due to holes or soot build up
3) MAF sensor issues

Is there anything else I should look at also? I'm just hoping its not an issue with vanes sticking internally in the turbo itself.

Thanks for your help.
GD

The sticking due to the soot seems to be a big problem with them..

If you use google,,there seems to be a fix for that using oven cleaner without havin to take off the turbo.

Not sure how well it works,,or what the results would be,to be honest.

http://www.audi-sport.net/vb/a4-s4-forum-b5-chassis/107121-un-sticking-your-tdi-vnt-turbo-vanes.html


You could also have a read through this....Good info there..

http://www.myturbodiesel.com/1000q/multi/limp-mode-TDI-fix.htm





.

George Dalton

The oven cleaner works as a short term fix on turbos with vanes that are only slightly stiff. I tried it on a few cars, 6 months was the longest it lasted for.

GeneralDisorder

Thanks for the responses Guys, at least it looks like i'm on the right trail.

If the vanes variable vanes in the turbo as sticking, is it possible to clean easily or does it require an overhaul/re-build of the turbo unit.

Is the actuation of the vanes the easiest place to look at first rather than checking if the vanes themselves are sticking?

The issue is wrecking my head, makes it squeaking bum time when overtaking hoping the car won't go into limp home mode

George Dalton

It is best to do a complete overhaul of the turbo in my opinion.