How easily should the vnt actuator rod move?

D

darioc

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Jul 3, 2009
Location
CT
TDI
99 Golf 2dr
My 99 golf has been going into limp mode while on the highway for quite some time now. I'm in the process of purchasing a ross-tech cable, but until then the generic codes I have are 1441, 1549, and 1550. I have removed the n18, and will eventually remove the egr cooler and pipes so that is why the egr code is present. I have replaced the n75 and all vacuum lines and am now onto the turbo. On startup, the vnt arm/rod moves very slightly and not at all when revving the engine. I can move it by hand about 1/2" but it has some resistance. My next step is to disconnect the rod from the arm for the vanes and see how easily the arm moves. Should the arm/rod move when revving the motor? Should there be any resistance on either? The vnt does hold vacuum and the car drives well, aside from slowdown shudder and a bad trans mount :( causing some unwanted movement.

Any ideas or other ways to test the vnt? If I have to remove the turbo and clean it, so be it. But if I don't have to, all the better ;)
 
Last edited:
oilhammer

oilhammer

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outside St Louis, MO
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There are just too many to list....
It should move reasonably easy, and spring back to its stop. You can use a vacuum pump directly on the VNT actuator to see how it travels.

When you say limp mode, what DTC is the car recording? If it is overboost, it could very well be the VNT actuator mechanism and/or the vanes inside are sticking/stuck.

Only fix for that is a new turbo or an attempt to take apart, clean and free up your existing turbo.

Is your splash shield(s) missing?
 
D

darioc

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Joined
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Location
CT
TDI
99 Golf 2dr
oilhammer said:
It should move reasonably easy, and spring back to its stop. You can use a vacuum pump directly on the VNT actuator to see how it travels.

When you say limp mode, what DTC is the car recording? If it is overboost, it could very well be the VNT actuator mechanism and/or the vanes inside are sticking/stuck.

Only fix for that is a new turbo or an attempt to take apart, clean and free up your existing turbo.

Is your splash shield(s) missing?
Click to expand...
It does move and spring back to its stop, but how easily is easily haha?

I just edited my op, but 1441, 1549, and 1550 are the generic codes I have pulled. (vag-com will be purchased shortly :) )

I recently installed a dieselgeek panzer, but before that the oem plastic shield was installed.
 
BobnOH

BobnOH

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May 29, 2004
Location
central Ohio
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New Beetle 2003 manual
darioc said:
...................Any ideas or other ways to test the vnt? If I have to remove the turbo and clean it, so be it. But if I don't have to, all the better ;)
Click to expand...
Get under the car, cover removed, and observe the actuator rod while someone starts the car. It should move slowly to full travel.
 
D

darioc

Well-known member
Joined
Jul 3, 2009
Location
CT
TDI
99 Golf 2dr
BobnOH said:
Get under the car, cover removed, and observe the actuator rod while someone starts the car. It should move slowly to full travel.
Click to expand...
Ok, it does. Should it move when revving?
 
BobnOH

BobnOH

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May 29, 2004
Location
central Ohio
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New Beetle 2003 manual
I don't believe you can check much beyond that in the driveway. Have you unplugged the MAF and driven the car to see if there is a power improvement?
The 1549 and 1550 codes point to the N75, according to the Bentley. You might try swapping the N75 and the N18
 
D

darioc

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Location
CT
TDI
99 Golf 2dr
BobnOH said:
I don't believe you can check much beyond that in the driveway. Have you unplugged the MAF and driven the car to see if there is a power improvement?
The 1549 and 1550 codes point to the N75, according to the Bentley. You might try swapping the N75 and the N18
Click to expand...
I'll unplug the maf and drive it to lunch to see what happens. The n75 has been replaced with a new unit and the n18 is removed.
 
D

darioc

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Joined
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Location
CT
TDI
99 Golf 2dr
MAF being unplugged made things worse. It was like I was in limp mode all the time. I actually thought that I had it figured out yesterday. Monday I lubed up the actuator arm/rod and I didn't enter limp mode on the highway on the way to and from work yesterday like I do every other day. But today back to the same. Limp mode many times. Maybe I have to keep lubing it up? Anything else I can check before I tear the turbo out of this thing?
 
jettawreck

jettawreck

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Aug 2, 2004
Location
Northern Minnesota-55744
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2001 Jetta and 2003 Jetta
I don't think you will have much luck with just lubing it up, at least I haven't. It'll be OK for a few days and back to same old deal. It's the ring that changes the vane's pitch that gets sticky and the process of lubing the linkage just gets you to exercise the whole mechanism, which loosens it up temporarily.
There is a thread about chemical cleaning vs removal and cleaning that I need to look into some more. I need to do one or the other.
My VNT linkage has a very definite "catch" in it. I may just change out the turbo-I have a spare on the shelf w/only 30K on it. Not enough time. :eek:
 
D

darioc

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Joined
Jul 3, 2009
Location
CT
TDI
99 Golf 2dr
jettawreck said:
I don't think you will have much luck with just lubing it up, at least I haven't. It'll be OK for a few days and back to same old deal. It's the ring that changes the vane's pitch that gets sticky and the process of lubing the linkage just gets you to exercise the whole mechanism, which loosens it up temporarily.
There is a thread about chemical cleaning vs removal and cleaning that I need to look into some more. I need to do one or the other.
My VNT linkage has a very definite "catch" in it. I may just change out the turbo-I have a spare on the shelf w/only 30K on it. Not enough time. :eek:
Click to expand...
I am beginning to feel the same way. If I lube it, it only operates properly for a day.
 
jettawreck

jettawreck

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Northern Minnesota-55744
TDI
2001 Jetta and 2003 Jetta
D

darioc

Well-known member
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Jul 3, 2009
Location
CT
TDI
99 Golf 2dr
Tom W. said:
Here's the link:
http://forums.tdiclub.com/showthread.php?t=246287&highlight=chemically+cleaning

Costs less than $10, can be done by a novice, works 100% of the time if your problem is a carboned up VNT, and worth trying before going to something more expensive/extreme like tearing down your VNT or replacing it.
Click to expand...
Going to try the route of removing the intake/egr and spraying into the exhaust side this weekend. I would remove the downpipe and perform the more thorough procedure of spraying directly into the exhaust housing but I broke one of the studs the last time I removed the downpipe so I don't want to tamper with it unless I absolutely have to. Will post results as soon as I am done. Thanks a lot for the link, good work!
 
Tom W.

Tom W.

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Raleigh, NC
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mash-up GettaTDI150, 1986 Jetta Delux D, 2005 Passat TDI sedan
good luck- post your results!

Any questions, post on the chemicaly clean your turbo link- the guys are really helpful.
 
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