Losing my mind... Need turbo advice...

[DrFaustus]

Poking your head around the engine looking for a boost leak is okay, but this is much better:

http://www.myturbodiesel.com/1000q/multi/boost-leak-tester-DIY-check.htm

It's difficult to have your head and hands around an engine when your turbo is at full boost. This is the solution.

 

[theinternot]

Thanks for link.

I've actually built a few a couple of these and wasn't able to detect any boost leak anywhere... not a squeak.

However, the video of the exhaust side leak is very similar to the type of noise I am hearing.

Poking your head around the engine looking for a boost leak is okay, but this is much better:

http://www.myturbodiesel.com/1000q/multi/boost-leak-tester-DIY-check.htm

It's difficult to have your head and hands around an engine when your turbo is at full boost. This is the solution.

 

[theinternot]

Update

Hi Rattler,

I do have a bit of an update. However, I wasn't able to get to the logs as I'd hoped.

Spent a few hours looking over the exhaust side...

Inspected:

- Downpipe flexpipe: no signs of exhaust leaking (thought I had found a crack in the downpipe, but turned out to be some extra weld solder? that flaked off)

- Visually inspected the turbo to downpipe connection... didn't see any signs of leaks... does this gasket fail often?

- Also inspected the exhaust manifold (as best as I could)... i couldn't see the inner most piece of the gasket as it was blocked by the egr flex pipe. There seems to be a lot of sticky oil buildup in that area. I don't know if it's residue from valve cover leaking, or from spraying the manifold area with brake cleaner testing for leaks... but I think if there is a problem with the manifold gasket anywhere it would most likely be there.

Found a leak from exhaust clamp with pressure test

I tried to do a reverse boost leak test and made an extra cap for the exhaust to block it off and push some air in to see if there is a leak... same as a smoke test without the smoke.

My only hope in doing this was to see if I could hear any possible leak in the exhaust path up to the turbo/downpipe connection.

When I put air in, I got an air leak immediately. I was excited at first as I thought it was coming from inside the engine bay, but realized it was coming from the exhaust clamp. Then I noticed that the air stream was causing a carbon deposit and soot build up on the back of the cat.

So, is the exhaust highly pressurized that far down the exhaust line?

Could this leak cause problems with my turbo's delayed onset?

After that, I took the pressure cap and fit it on the end of the downpipe and ran some air into it... it held all the pressure (about 15 lbs.) no leaks at all.

I fixed the leak by spreading a thin layer of hi-temp RTV around the the downpipe and cat ends and inside the clamp... then clamped it down tight and even.

My first impressions after driving it around the neighborhood in a good variety of traffic and terrain is that the boost seems to be responding faster, I hear the turbo whistle much clearer now, too.

I am still getting a quick shhhhhhhh if I get on the pedal hard... but it seems to be driving a bit better...

But, I am always proven wrong the next day when I think things are better, so I will give it a few days before I make a determination one way or another.

Conclusions

Nothing concrete.

I also noticed that if I rev the engine a few times hard for a few seconds, thin streams of light gray smoke start rising right from between the area where the manifold, egr valve, turbo are. It only last for few seconds and dissipates quickly... is this normal?

Not 100% sure there isn't a crack in the manifold gasket somewhere. I guess the only way to know for sure is to take it off?

Really feel like I am coming back full circle to thinking the initial shhhh noise is the solid flywheel or damper springs vibrating on the clutch disc.

Thanks

How is the hunting going?

I picked up my car last night and the burst of power at ~2600RPM is slightly better. But the tune and increase in fun has me distracted at this point! The mechanic said that the burst will be there until I replace the cooler. Lame!

Good luck today, let us know what you find!

 

[kooyajerms]

I don't see how that smoke coming from the turbo/ exhaust manifold area is normal. Check those gaskets, as in time to take that turbo off.

It's pointing more and more to a bad seal on a metal gasket. You also need to make a better seal/weld on that cat to downpipe/exhaust pipe that you jimmied.

I'd say you're progressing, not coming full circle.

 

[theinternot]

Agreed. The smoke isn't normal.

So, is removing the turbo as big of a pain as it looks?

Any tips or tricks that might help in the removal process?

Thanks kooya.

I don't see how that smoke coming from the turbo/ exhaust manifold area is normal. Check those gaskets, as in time to take that turbo off.

It's pointing more and more to a bad seal on a metal gasket. You also need to make a better seal/weld on that cat to downpipe/exhaust pie that you jimmied.

I'd say you're progressing, not coming full circle.

 

[theinternot]

Udpate

I had another look at things today.

Couldn't make the smoke appear at all today.

Got it up to temp, drove hard for a bit... turbo response is better... significatly. But, I can still make the noise happen on command.

I didn't notice any hint of exhaust smell coming from behind the engine. I literally stood over my engine while it was idling and sniffed around the firewall area.

 

[kooyajerms]

Bit harder for the leak to show itself when it's idling, not much boost on it remember?

you'll need to search on how to remove the turbo, don't know if the intake has to come off on this one, or if you pull from the bottom.

Really, you just need to loosen what's around the turbo, and take off the 8 13mm nuts that hold the manifold on, and see where that oil leak is coming from. You don't have to totally remove the turbo if you're gonna replace gaskets and hope for the best. Maybe your egr cooler/egr/bits required two gaskets versus one on a specific mating section.

Check myturbodiesel.com for a how-to, he may have one.

 

[greengeeker]

I don't see how that smoke coming from the turbo/ exhaust manifold area is normal. Check those gaskets, as in time to take that turbo off.

It's pointing more and more to a bad seal on a metal gasket.

If you have an oily mess in the area, I'd start with the intake manifold and then progress to the trubo but that's just me.

 

[kooyajerms]

Yeah looking at it again maybe I shouldn't have jumped to conclusions. Did the turbo or intake ever come off to even allow for a leaking gasket? I thought the egr came off at one point.

 

[theinternot]

EGR has been replaced. I didn't need to remove the turbo or manifold to do it, though.

Nothing else has been removed from that area of the engine.

Is it possible for the flex pipe heat shield made of the wire mesh to just vibrate and make noise?

There is no leak in pipe itself.

Also, would a boost leak test reveal a leak in the intake manifold?

Yeah looking at it again maybe I shouldn't have jumped to conclusions. Did the turbo or intake ever come off to even allow for a leaking gasket? I thought the egr came off at one point.

 

[theinternot]

Another Update...

OK,

I finally broke down and took the car to the dealership.

Took the tech around for a test drive, showed him how to make the noise, explained any mods to my car (tune, SMF, etc...)

Got a call back yesterday saying they needed to keep the car overnight. They ran all the same boost leak tests, pressurized the system, etc... they replaced one intercooler gasket... no leaks at all.

The tech seems to thing that the turbo is overboosting. I don't think they ran any logs to determine that for sure. I will do that tonight with VCDS. After researching overboosting last night, I am inclined to agree that this may be the problem... just don't know why.

They said the N75 valve was not malfunctioning... and there are no vacuum leaks. Are the vanes sticking?

They want me to remove the GIAC chip and bring it back to them. They seem to think it is the problem. Does this sound right?

And now for a bit o' the funny... I got a call from the service rep this morning stating that it was ready for pickup and that "the car is running great, except for that noise it's making." Thanks genius! *facepalm*

 

[kooyajerms]

Hahaha.

Well at least they SEEM to be troubleshooting your issues... much more than I expected from them. You do know they are more than happy to tell you it's a turbo issue... But the question is, can you trust them with that diagnosis. Good luck.

 

[theinternot]

More info...

Just picked my car up.

I was looking over the work order and saw this line:

"CHECKED MVB 10 FOR ACTUAL CHARGE PRESSURE VALUES 2575 mbar. OVER BOOSTING."

Does this mean the actual boost value was 37 PSI????

What the heck would be causing that? I don't think a chip from GIAC would be released that would cause that much boost deviation. But, VW wants me to remove the chip and bring it back.

Here is a pic of the work order:

Thoughts?

EDIT: Just wanted to mention that I have never gone into limp mode with this car.

 

[theinternot]

VCSD Boost Logs

I am definitely making a lot of boost... in excess of 35 psi.

I can't imagine a stage 1 tune would be creating that much boost... so the question is what is causing this to happen?

3 x passes 1500 rpm to redline WOT

- https://spreadsheets0.google.com/ccc?key=tJUkOpgbM04iMTmkNHVW48Q&hl=en#gid=0

- https://spreadsheets1.google.com/ccc?key=tn-Ikw9A_6kwiSh8GoMiGig&hl=en#gid=0

- https://spreadsheets2.google.com/ccc?key=tsSBlFnscQeHW3YCcUs_mWg&hl=en#gid=0

1 x pass city driving/stop lights/approx. 2 miles

- https://spreadsheets.google.com/ccc?key=0Al66M7BoTuTBdE5sT1prY0trZTk0clItc1Rpd3JqcWc&hl=en#gid=0

 

[kooyajerms]

Your imagination is causing it to happen =)

When you are reading vag com logs (good job doing that), you have to remember that ambient pressure is included. So look at your log and subtract 950mbar from each of the numbers. You subtract what mbar is reading at idle.
http://forums.tdiclub.com/showthread.php?t=245144

So your highest boost pressure was actually 18 sustained and a 20 psi spike. It's tracking well, but I don't know the limitations of your stock turbo, look around.
It does seem as if your n75's duty cycle is reading lower than I would expect (mine ran in the 60 to 80 range when doing logs), maybe your actuator needs adjustment or it's sticking.
Ever touch the locknut on the actuator rod?

Don't know if this indicates your noise issue, or if there are problems inside the turbo.

Use this so you can "See" what your logs look like on a graph. Download the program, then open your log with it. http://forums.tdiclub.com/showthread.php?t=201161

Jeremy

 

[jettacaper]

was your engine blowing blue oil smoke with seals gone ??

That's a bit dramatic to get rid of her based on the turbo sounds. You may not have luck determining the turbo is bad with a visual inspection, or even checking shaft play. My turbo that went out on me, had no significant shaft play x or y axis. But the seals were shot, and there was no way I could have visually noticed that.

How long has the chip been in? Did it cause the slipping or has it gradually become worse?

Can you do a vcds of log channel 11? That can show us what requested and actual boost is.

What's a thousand dollars if you get to keep the vehicle? Not saying it's for sure a turbo replacement in your future, but what if?

 

[kooyajerms]

http://forums.tdiclub.com/showthread.php?p=3124220but let's help theinternot out on his.

 

[theinternot]

ahhhhhhhh! OK, I was freaking out there!

Thanks, Jeremy.

From what I can gather, the recommended max sustained boost is 18 psi with spikes to 20. So, it seems I am still within the upper limits of the turbo. So, according to VW I am overboosting, but in actuality it is probably just my tune.

So, it would appear that my turbo may be trying to tell me it is on its way out?

Nope. I've never touched the locknut on the actuator, but I will check tonight to see if it is sticking.

I will graph those logs tonight as well.

If the actuator isn't sticking, should I just get another N75 and swap it out? I remember reading something about an N75 J valve... does that sound familiar?

Thanks,

John

Your imagination is causing it to happen =)

When you are reading vag com logs (good job doing that), you have to remember that ambient pressure is included. So look at your log and subtract 950mbar from each of the numbers. You subtract what mbar is reading at idle.
http://forums.tdiclub.com/showthread.php?t=245144

So your highest boost pressure was actually 18 sustained and a 20 psi spike. It's tracking well, but I don't know the limitations of your stock turbo, look around.
It does seem as if your n75's duty cycle is reading lower than I would expect (mine ran in the 60 to 80 range when doing logs), maybe your actuator needs adjustment or it's sticking.
Ever touch the locknut on the actuator rod?

Don't know if this indicates your noise issue, or if there are problems inside the turbo.

Use this so you can "See" what your logs look like on a graph. Download the program, then open your log with it. http://forums.tdiclub.com/showthread.php?t=201161

Jeremy

 

[theinternot]

Lots of black smoke according to the VW tech.

I have a hard time seeing any smoke while I am driving.

 

[theinternot]

Crap. Maybe I should just get a new turbo just to be safe?

I definitely can't financially handle a blown engine.

http://forums.tdiclub.com/showthread.php?p=3124220but let's help theinternot out on his.

 

[kooyajerms]

nonono, don't freak out. I posted that to answer his question. I responded with, let's help you, don't focus on mine.

Leonard has no spots open in the next two weeks?

Did you fix all the exhaust/downpipe welds/leaks?

 

[theinternot]

hehehe... i am starting to lose it!

No leaks at all now.

I am going to call him and see if he has time next week.

nonono, don't freak out. I posted that to answer his question. I responded with, let's help you, don't focus on mine.

Leonard has no spots open in the next two weeks?

Did you fix all the exhaust/downpipe welds/leaks?

 

[kooyajerms]

Howgoezit?

 

[theinternot]

I think I located the source of the noise. Not gonna say just yet though... will know for sure Saturday and do a post then.

Thanks for bumping the thread!

Howgoezit?

 

[theinternot]

RESOLVED... for realz this time! ;-)

HI all,

I wanted to do a follow up post, as I have isolated and fixed the problem... it only took 3.5 months!

This noise has been very hard to diagnose because there were several other noises occuring simultaneously and concurrently with the normal turbo spooling whistle. This gave the impression that the leak was generating from airflow. However, the final underlying noise was mechanical. The only way to figure it out was to mic the engine after fixing each one and see what the noise differences told me.

I had both a private mechanic and a VW tech look at it, and both diagnosed the noise incorrectly. I gave them every bit of information about the car including mods, changes to the clutch, etc.. and they still misdiagnosed.

The noises so far have been:
- EGR Cooler
- Exahaust leak at the DP/CAT coupler
- Bad right front wheel bearing
- Normal turbo whistle
- Undetermined clutch noise

Exacerbated by:
- Trashed motor and transmission mounts
- Whining gear box

The final fix was to remove the Valeo SMF Kit and replace it with the dieselgeek LUK DMF.

Here are the clutches in order (Valeo, original Sachs, new LUK):

After the swap all the problems went away... it is smooth as silk now. I was amazed at the overall NVH reduction. The interior rattles have subsided tremendously, the pedals don't vibrate hardly at all, and the scraping-hissing-grinding noise during acceleration is 100% gone. The surging feeling when accelerating is gone. And now I can say, with certainty, that the delay in turbo kicking in, whicn I had noted felt like the clutch slipping, was in fact the clutch slipping. The engagement is smooth and perfect... not grabby at all like the Sach's was before I took it out.

Not sure if the clamping force on the Valeo clutch wasn't enough. I only have a stage 1 tune on my TDI. But, the back of the clutch disc looked to be glazed, and the wear marks on the front of the clutch seemed to only be on the very center and about 3/4" wide... so it looked like the pressure plate and clutch were only touching over a very small surface area. Also, the metal dowel-like pins on the very top of the pressure plate (9 of them) that hold the pressure fingers were all scraped and worn down. So they were rubbing on something. But, there was no indication of rubbing on the clutch fork at all.. so no clue where or how that happened.

Also, upon removing the transmission, a piece of the clutch fork retaining clip fell out. The clip had snapped.

Seeing as I was working on this last Saturday, I tried calling around to the dealerships (only 1 was open on Saturday and were an hour away... but they didn't have the clip in stock anyway), and some auto parts stores. No one had the clip. So I made one myself out of galvanized wire. It took me about 7 or 8 tries to get it right. But, it worked perfectly.

FINAL CLIP:

PROTOTYPES:

INSTALLED:

I also checked the springs in the clutch hub. There are 4 double coil packs. I plucked each one like a guitar string, and one of the coil packs reverberated and resonated the whole hub.

I think the Valeo flywheel was not balanced correctly either. I noticed welded balancing weights on the the back of the LUK flywheel. The build quality of the LUK is far superior to the Valeo, too... especially the throwout bearing.

SO.. what was the noise... not 100% sure... could have been the springs vibrating, might have been the clutch slipping noise, maybe it was the clutch fork rattling. Perhaps, there was a minor clearance issue and something was scraping (but, I don't know how there could not be indicating marks left). Most likely it was a combination of all these things, and showing itself as a single noise.

The turbo is fine. The VNT actuator holds a vaccum and actuates smoothly. N75 may or may not need replacing, but for the moment it's fine.

I have prematurely thought I fixed the problem in the past, so I made sure I did a lot of driving before I was sure it was gone... and it is. I never drove my car new with the Sachs DMF, so can't say if it was any good new, but it sucked by the time I got it.... so I didn't know any better and just thought DMF's sucked in general. But, this LUK DMF is so smooth and quiet. It is supposed to have more clamping force than the stock Sachs one, and supposedly is more durable. I wish I had gone this route to begin with.

Thanks to everyone who gave input and support both on this thread and the several others I have created at various stages of diagnosing this problem.

I am happy it's over, but pissed it took so long to diagnose... and now I have a $400 worthless piece of metal on my garage floor.

Happy dieseling,

John