Another Limp mode with graph

cbman18j

cbman18j

Veteran Member
Joined
May 29, 2015
Location
Savannah
TDI
03 Jetta TDI (First Diesel)
To make a long story short, I replaced my VNT actuator and did a lot of other things in order to clear my limp mode. Which I thought I had fixed surprise, surprise after a couple days on one of my 1200 mile weekends I go into limp mode on a hill outside Columbus, GA on HWY 80 in a Alabama. Luckily had the laptop with me so I logged a couple of runs on my way home another 300 miles away. I have attached my data
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Here is some background if anyone is interested.http://forums.tdiclub.com/showthread.php?t=448511
 
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cbman18j

cbman18j

Veteran Member
Joined
May 29, 2015
Location
Savannah
TDI
03 Jetta TDI (First Diesel)
Does anyone have any thoughts on this? I am still fighting this. The only thing left that I can think of is a marginal N75? I only get the limp mode maybe once a month but it is still annoying I was hoping I could resolve this.
 
K

keaton85

Veteran Member
Joined
Feb 26, 2011
Location
Camden, ME
TDI
Golf MK4
Have you checked your MAF sensor values with VCDS? Since I bad MAF sensor can cause limp mode as well.

If the VNT vanes are not clean enough, they can still get hung up and cause overboost, thus a limp mode.
 
cbman18j

cbman18j

Veteran Member
Joined
May 29, 2015
Location
Savannah
TDI
03 Jetta TDI (First Diesel)
What should I look for concerning MAF values and when? I forgot add when I swapped the VNT actuator my vanes seemed to free.
 
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CoolAirVw

CoolAirVw

Vendor
Joined
Nov 9, 2005
Location
Kansas City Missouri
TDI
Jetta
I dont see anything in the graph. Seems to be a good working system.

You might want to graph it when the problem happens.

Might want to include code and definition of the code.
 
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keaton85

Veteran Member
Joined
Feb 26, 2011
Location
Camden, ME
TDI
Golf MK4
Ive found a lot of the turbos will hang up every once in a while, no matter how was it has run for. I used to have limp mode only on really hot days on the highway in Florida. Once I was back up in New England, I would never get limp mode, even on the highway up from FL. So, just a little hang up or issue with cause it every once in a while.

The MAF sensor values are worth checking though...
 
cbman18j

cbman18j

Veteran Member
Joined
May 29, 2015
Location
Savannah
TDI
03 Jetta TDI (First Diesel)
I would get a positive boost deviation. Which would trigger my limp mode, cycle key then it would be gone for a while.
 
runonbeer

runonbeer

Maintenance EnthusiastVendor
Joined
Apr 15, 2002
Location
Austin, TX/Chapel Hill, NC
TDI
'00 Golf 02M, '10 Golf 02E, '02 UTE 02M
As Richard said, there is no problem with your plot there. You need to catch it in action.

Take a log in 5th gear at 70-75 mph and go up a big hill. It will probably limp at the top of the hill.

This may be a waste of time though as in most cases under these circumstances the problem is wear on the VNT control ring and you cannot practically fix it without simply replacing the turbo. Seems like a lot of people on here refuse to believe that a turbocharger is a wear item. I'm sure this post would have been just fine without the inflammatory editorial but there it is.
 
ugenetoo

ugenetoo

Veteran Member
Joined
Mar 26, 2012
Location
north maine
TDI
Two 03 wagons one 03 sedan All manual TDIs
My 03 5 speed ALH will almost invariably go into overboost limp mode when disengaging cruise control at around 75 and then trying to maintain speed with the footfeed.
That little hesitation always seems to foretell a limp mode coming.
 
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keaton85

Veteran Member
Joined
Feb 26, 2011
Location
Camden, ME
TDI
Golf MK4
The VNT vanes can get caught up once in a while, even just on the internals itself. The ring itself can be replaced easy enough. What I have found happens a lot is one vane will stick inside the housing, even when clean. So I lap down all the vanes so there is more clearance and plenty of room for error. Works perfect....
 
cbman18j

cbman18j

Veteran Member
Joined
May 29, 2015
Location
Savannah
TDI
03 Jetta TDI (First Diesel)
Thanks for the info. I was trying to make sure I had ruled everything out before I replaced the turbo. I haven't had my laptop with me to log the data but here is some more info I can run 80 up a hill or level fine but if I decided I need to accelerate to 90 for what ever reason without slowly rolling into max throttle it will go into limp mode.
On a side note this past weekend I was on I-95 between GA and PA. The jetta ran well no limp mode and I was able to keep up with the flow of traffic screaming up and down the highway.


runonbeer said:
As Richard said, there is no problem with your plot there. You need to catch it in action.

Take a log in 5th gear at 70-75 mph and go up a big hill. It will probably limp at the top of the hill.

This may be a waste of time though as in most cases under these circumstances the problem is wear on the VNT control ring and you cannot practically fix it without simply replacing the turbo. Seems like a lot of people on here refuse to believe that a turbocharger is a wear item. I'm sure this post would have been just fine without the inflammatory editorial but there it is.
Click to expand...
 
cbman18j

cbman18j

Veteran Member
Joined
May 29, 2015
Location
Savannah
TDI
03 Jetta TDI (First Diesel)
Just as a follow up. I replaced my N75 and it appears to have solved my issue. I will update if something changes.
 
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