For anyone with limp mode

ghohouston

Veteran Member
Joined
Apr 2, 2013
Location
Lewisville, Texas
TDI
2001 Jetta Sedan TDI 5 Speed
Just a tip, i pulled my turbo today to clean the vanes, again, for probably the 4th or 5th time this year. Kept getting 4th and 5th gear limp mode. I'd clean the vanes/turbo properly, everything would be good for a few weeks, then back to limp mode. I have been taking the car up over 4k rpms multiple times a day, and they were still sticking. My car does burn a good bit of oil, so i attributed that as my cause of the sticking vanes. Note that before today, i never saw any buildup other than really just normal looking carbon on the vanes.

So, i pull my turbo today, seperate the housings, and find only a small section with a hardened substance on the vnt ring/vanes. This section, when the turbo is mounted on the car, is roughly between the 10 p.m. and 10 a.m. position. My light bulb immediately went off. My valve cover has been leaking more than a little bit lately. I had not installed my new one yet due to a stripped bolt head. The oil had been making its way through the tiny air gap between the vnt lever and backing plate, into the exhaust housing, and to the vanes. Never would i have thought that small of a space would allow oil to enter the exhaust housing, but figured i would share, in case anyone is ever in the same boat i have been in, and verified proper function of all other components, but still or repeatedly getting limp mode.
 

wonneber

Top Post Dawg
Joined
Oct 12, 2011
Location
Monroe, NY, USA
TDI
2014 Jetta Sportwagon,2003 Jetta 261K Sold but not forgotten
I had over boosts for a while.
When I installed a boost gauge I saw I was easily getting around 25 lb boost.
Vacuum testing the actuator (was new already) and it was in the normal range.
I lengthened the actuator until I had 20 lb (or so) on normal take off which also dropped quickly.
I've only had 1 limp mode a while back.
When I do my next oil change I plan to lengthen once more just 1/4 turn.
Can you log the boost requested, & actual, MAF requested, & actual, and the N75?
That could give you a better idea on the actuator setting.
I can't picture oil getting sucked in if the shaft is in the pressurized exhaust side.
 

ghohouston

Veteran Member
Joined
Apr 2, 2013
Location
Lewisville, Texas
TDI
2001 Jetta Sedan TDI 5 Speed
My actuator is set exactly where it needs to be, via the write ups online, starts moving within 3-5 in hg, and stops at 18. I couldnt picture it either, until i seperated the turbo, and like i said, the oil was at the very top of the vnt ring/vanes. It has been heated and hardened up. This was the worst i had seen it. The car has also been to a well regarded shop in the area to make sure all sensors/timing, etc were in proper order. I get what you're saying about the pressurized exhaust side. My only theory is that the oil dripping on the lever daily, for months, kept working its way into that small gap, regardless of pressure. And then, when the car is shut off, the oil on the shaft will find its way through that gap.
 
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