Turbo Outlet hose question

Dan99TDI

Well-known member
Joined
Dec 17, 2013
Location
Nevada City, CA
TDI
ALH going in a 56 CJ5, B5.5 tdi wagon
Hi TDI Club,
I bought a B5.5 passat tdi knowing it had a P0299 and having read about it pretty thoroughly.

I have a potential culprit in the turbo outlet hose that doesn't look right- here is a picture I snapped. I'm thinking air may be leaking past the hose where the housing has a gap from the hose- but I don't know how this hose is supposed to seal, I haven't been able to find any pictures online.

https://drive.google.com/file/d/1dgcBQQzW-WddR5TNP5bq7HbZEy6EttwZ/view?usp=sharing

To cover the bases, The engine is producing vacuum, which at idle smoothly moves the VNT lever to the stop and holds it there- registering about 20" of mercury.
Thanks!
 

Dan99TDI

Well-known member
Joined
Dec 17, 2013
Location
Nevada City, CA
TDI
ALH going in a 56 CJ5, B5.5 tdi wagon
Found my OBD Dongle, cleared the code, and the car runs great.

Graphed the boost on a quick jaunt up my backroad, and it seems to be creating and controlling boost.
https://photos.app.goo.gl/cMPykAoMongXi9iw9

I'm running torque pro, so I don't seem to be able to see requested boost.

The only thing I can think at this point is either:
1: the computer is referencing another sensor and thinking the comparison doesn't make sense
2: The computer thinks the boost is taking too much time or control to make the boost
3: Magic.

I guess I'll keep updating this in hopes it'll help someone else down the road.
 

auntulna

Veteran Member
Joined
Mar 13, 2005
Location
Springfield, MO
TDI
05 GLS Passat wagon, mit panzer plate
Yikes! That is some improvising you got there, I wouldn't want to leave town with that setup. It looks like whoever was there didn't want to pay for the right hose, or lost the clips, or one of the clip retainers broke off.
 

Dan99TDI

Well-known member
Joined
Dec 17, 2013
Location
Nevada City, CA
TDI
ALH going in a 56 CJ5, B5.5 tdi wagon
Yeah looks that way- there's actually a little lip that might be the swaged oring holder, and the hose clamp may be a poor replacement for the clip. I have some time today so I'll be checking the intake tract.
 

Dan99TDI

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Joined
Dec 17, 2013
Location
Nevada City, CA
TDI
ALH going in a 56 CJ5, B5.5 tdi wagon
Well, I drove it yesterday and noticed an interesting facet.

I only get the code under moderate throttle- cruising down the highway at 75 seems to be the Achilles heel. If I hammer down on it, it seems to run great.

This implies to me a relatively small boost leak.

New o-rings and retainer clip about to be ordered.

Happy Memorial Day!
 

Passat'n Adventure

Well-known member
Joined
Feb 17, 2013
Location
Augusta, GA area
TDI
05 Passat GLS Wagon - Deleted and 5 speeded
Well, I drove it yesterday and noticed an interesting facet.
I only get the code under moderate throttle- cruising down the highway at 75 seems to be the Achilles heel. If I hammer down on it, it seems to run great.
This implies to me a relatively small boost leak.
New o-rings and retainer clip about to be ordered.
Happy Memorial Day!
Don't forget to order the correct hose too.... This setup looks undersized for the air going through it. The original hose has a slight taper to it and metal ends on it that will seal correctly - with the correct clips. The top and bottom are different clip numbers. I can tell you that from experience.
 

Dan99TDI

Well-known member
Joined
Dec 17, 2013
Location
Nevada City, CA
TDI
ALH going in a 56 CJ5, B5.5 tdi wagon
Pulled individual pieces apart, they all look to be correct.

Pulled the clip off the turbo outlet, its the correct hose and the clip just needed to be bent slightly to hold the hose.

Built a home made smoke leak tester and could not find a leak.

Took another boost log against rpm, and it builds 2.5 bar (absolute) but it doesn't come in until 3000 rpm.

Turbo was supposed to be new, and looks relatively new.

Changed the fuel filter and it now takes longer to set the code, but it still sets.

I'm left to wonder about injectors, plugged cats...
 

QuickTD

Veteran Member
Joined
Feb 25, 2002
Location
SW Ontario
TDI
2003 Audi A4Q 5spd 2.0 TDI 2056VK R783, 2006 Audi A4Q 6spd 2.0 TDI, 2007 A4Q 6spd 2.0 TDI
The problem is manifesting only at light throttle, indicating a lack of boost at low engine speed and load. Most likely culprit is the vane control system. I'd check vacuum lines again, and possibly replace the N75.

Plugged cat would be worse at high speeds and bad injectors are virtually unheard of, at least until you reach 400-500k.
 

oilhammer

Certified Volkswagen Nut & Vendor
Joined
Dec 11, 2001
Location
outside St Louis (where it's safe)
TDI
There are just too many to list....
Or some junk Chinaboost replacement turbo. The OEM Garret turbos are not high failure items. Lots get replaced for no reason other than someone could not properly diagnose a boost system.

I've had to take so many of those off and chuck them in the recycle bin. :rolleyes:
 

Dan99TDI

Well-known member
Joined
Dec 17, 2013
Location
Nevada City, CA
TDI
ALH going in a 56 CJ5, B5.5 tdi wagon
The problem is manifesting only at light throttle, indicating a lack of boost at low engine speed and load. Most likely culprit is the vane control system. I'd check vacuum lines again, and possibly replace the N75.
Plugged cat would be worse at high speeds and bad injectors are virtually unheard of, at least until you reach 400-500k.
Yeah, the plugged cat didn't make sense after I thought about it.

Glad to hear on the injectors.

The turbo appears to be genuine Garrett.

I guess I'll run through the vacuum diagnostics once more. Can the turbo be clocked against the vane system where it could appear in spec from the actuator but actually be out of spec?

Also, I'm thinking of shortening the actuator despite it appearing in spec- am I correct in thinking I can't really do any damage by doing this as long as I don't overboost it?

One check I did to make sure I wasn't over speeding the turbo- I compared MAP readings to boost and rpm- at 3500 rpm and 2.5 bar i was seeing ~140g/s which matched conditions closely enough for me to have a little peace of mind
 

oilhammer

Certified Volkswagen Nut & Vendor
Joined
Dec 11, 2001
Location
outside St Louis (where it's safe)
TDI
There are just too many to list....
You can work the VNT actuator with VCDS in the Basic Settings. This is the quickest, easiest, least troublesome way. And on the BHW, it is super easy to actually SEE it from above. That is how you check the control side vacuum. It takes 20 seconds.

If you do not have the correct scan tool, get one. You'll be way ahead.

I use a smoke machine to check for boost leaks, although in some cases the smoke machine's meager 3 PSI or so simply is not enough to reveal one that perhaps "opens" when under major boost, like a split in one of the charge air hoses. But it makes quick work of finding leaking quick connects, be it from the tabs being worn through (especially common on the BHW's 'S' shaped hose off the turbo) as well as the seal rings on all the connections, and the all-too-common damaged from a crash cracks in the intercooler.
 

Dan99TDI

Well-known member
Joined
Dec 17, 2013
Location
Nevada City, CA
TDI
ALH going in a 56 CJ5, B5.5 tdi wagon
Well, digging into it this morning I figured out that appearances aren't always what they seem. I do appear to have a Chinese knock off turbo, with the actuator adjusted all the way to the top to boot. I should've looked closer.
 

Dan99TDI

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Joined
Dec 17, 2013
Location
Nevada City, CA
TDI
ALH going in a 56 CJ5, B5.5 tdi wagon
Just to be sure, I ran through all the diagnostics at hand one more time.
Boost hoses all seem in order
Vacuum hoses all hold vacuum
Vacuum pump generates enough vacuum
Actuator moves all the way to the stop with 18" applied
Computer moves actuator to the stop when I start the car

And with all of that in order, I decided to replace the Chinese junk turbo with a garret. Found a Passat at a pick n pull and yanked the turbo, put it on my car, and now I've gone from underboost codes to overboost codes, and I have boost basically off idle in all gears.

I seem to have an exhaust leak to fix, and I need to recheck my actuator settings, but I'm confident the turbo was my problem with underboost.

Thank you all for the help with the diagnosis!
 

Dan99TDI

Well-known member
Joined
Dec 17, 2013
Location
Nevada City, CA
TDI
ALH going in a 56 CJ5, B5.5 tdi wagon
Just to finish this off (because I hate incomplete threads when I find them on Google)

After turbo replacement, I was getting overboost codes.
Someone had glued the actuator, and I couldn't adjust it.

I also couldn't get to the clip to remove the actuator.

So this morning, I pulled the turbo again, swapped the actuator from the chinajunk turbo on, adjusted it, and put it all back together.

I was still over boosting, so I was getting ready to swap on the junkyard n75 i grabbed, but when i looked at the hoses again, i noticed the vacuum and actuator lines were switched- meaning the computer was trying to control pressure and was venting to the vacuum system, and the actuator was just sitting there with the vacuum reservoir holding it tight to the closed position.

Once this was corrected, the car drove fine, no codes. Just another case of needing to look closer and check the basics.

Anyways, thanks again to those that helped the diagnosis. I'll now close this thread and start my road warrior wagon build.
 
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