2006 tdi no power black smoke under 2000 rpm

I also believe I'm having a similar problem.
http://forums.tdiclub.com/showthread.php?t=322706
and apparently are a few other people...
http://forums.tdiclub.com/showthread.php?t=323661
This makes me think...

VCDS shows the turbo veines are either all or nothing it seems. It shows the turbo vein position at 100% and then it will drop to like 25% when the car takes off, as soon as I let off the acc. pedal it goes right back to 100%

Click to expand...

that its linked to this...

The problem is the electronic potentiometer vane position sensor on the turbo.

Click to expand...

One potential issue is a bad position indicator on the turbo as Harv said. You can check for this by watching Engine Measuring Block 43 field 2 as you cycle the turbo with a vacuum pump. You could also log this as you ran down the road, if you wanted, checking for issues. There is no source that I am aware of for these positioners except off of ruined turbos. If the posioner fails completely you should get a code.

Click to expand...

I've also tried unplugging both the EGR and ASV valves one at a time and both. Replaced all maintenance filters. Also replaced the N75 valve with no avail to the symptoms

I'm hoping someone can find the culprit that could be the root of all of these studdering/hiccup/black smoke, then full power symptoms.

The VNT vane stop screw must keep the vanes slightly opened so exh gas can both exit and spool the exh wheel. It simply needs adjusted a turn CW in towards the lever (2.5mm hex and 10mm nut). If vanes are totally closed, its like a potato in the tailpipe until exh gas pressure force exceeds actuator spring force and violently opens the vanes. ecu gives 80% duty cycle on tip-in. It won't release vac until boost is 14psi. Emp is 1.5 times or 21 psi. On the hot side. Note: no more than 5 threads max showing on bottom below nut

It's not too much trouble to adjust vane stop using a 10mm & vac pump to move down for access. I have also replaced the brm vnt actuator inplace w/o removing turbo. Just use m6x1 x 1/2", long SHCS for reinstall. Gotta remove air box rear heat shield and valve cover helps. Get car up on jackstands and remove belly pan for access.

The vnt actuator also needs setup properly including vps (vane position sensor) calibration using vcds, 0 - 100%. I have covered this in other threads.

Jeff

Here is a quick video, tells 10000 words.

Jeff

http://www.youtube.com/watch?v=mdXfxbyfmLg
http://www.youtube.com/watch?v=ZRSRS-VZ2yY

jsrmonster said:

The VNT vane stop screw must keep the vanes slightly opened so exh gas can both exit and spool the exh wheel. It simply needs adjusted a turn CW in towards the lever (2.5mm hex and 10mm nut). If vanes are totally closed, its like a potato in the tailpipe until exh gas pressure force exceeds actuator spring force and violently opens the vanes. ecu gives 80% duty cycle on tip-in. It won't release vac until boost is 14psi. Emp is 1.5 times or 21 psi. On the hot side. Note: no more than 5 threads max showing on bottom below nut

It's not too much trouble to adjust vane stop using a 10mm & vac pump to move down for access. I have also replaced the brm vnt actuator inplace w/o removing turbo. Just use m6x1 x 1/2", long SHCS for reinstall. Gotta remove air box rear heat shield and valve cover helps. Get car up on jackstands and remove belly pan for access.

The vnt actuator also needs setup properly including vps (vane position sensor) calibration using vcds, 0 - 100%. I have covered this in other threads.

Jeff

Click to expand...

Thanks Jeff,
I think that you are right on with this issue. I tried disconnecting the vacuum line from my turbo completely and the problem with the surging went completely away. The main issue that is happening with these turbos is just like Jeff is saying. The Turbo Veins are adjusted incorrectly and are not allowing exhaust gas to pass through. If exhaust cannot get out of the engine the engine is going to lag and dump fuel into the engine creating black smoke. As soon as the turbo begins to open a bit all the sudden all that backpressure is released and the car surges. For everyone experiencing this problem, try disconnecting your vaccuum line that goes into the VNT turbo actuator. I think you will be surprised how smooth the engine runs. It will have less power, but will show you that the turbo is actually causing the surging problem. I don't suggest driving all the time with the VNT vaccuum disconnected because the engine is much less responsive, but this test alone will narrow down the surging problem directly to the turbo.

A few questions:
Is there any advantage to replacing the VNT actuator rather than adjusting the nut? Also is there any risk of damage by adjusting the nut on the VNT actuator?

If anyone knows of the specific procedure for adjusting the turbo, please let me know. I have VCDS if that is needed. I think we are finally finding the solution to the problem.
Thanks for everyones input.

I have a 2006 Jetta BRM engine and I am no mechanic but I found a split in my intercooler hose(Bentley calls it a connecting duct) at the lower bracket that is bolted to the engine. To find this problem, I suspected that I had a vacuum leak) I borrowed my mechanics smoke machine and clearly showed the leak. I had a CEL, an inplausible MAF signal, and lots of smoke upon acceleration. I tried a different MAF and EGR, new N 75 valve and these did not help. The smoke was largely eleiminated when I left eith the MAF or EGR plug off.
I have another intercooler hose and planned to replace it but chose to JB weld the split due to problems getting the front clamp off. It has been a few weeks since doing this and all is well. No check engine light good boost and no smoke. It's worth checking those ducts for leaks.
Bob

Turbo adjustment

I am going to try and adjust my turbo stop screw tomorrow. I'll try to look up a previous post on how to do it, but I haven't seen it before as I've searched.

I logged a VCDS .csv file today on the way home. I drove it a little through town and some freeway driving and have a few questions. For one, the car seems to be more problematic when it's cold. In VCDS Engine measuring blocks 43 number 2, it shows 101.5% for about 1/4 of a mile or so, and acceleration is very slow with black smoke and pinging if I push harder on the accelerator pedal. The car surges all the sudden and the Turbo Veins open all of the sudden to about 20%. I have never seen the turbo veins go below 16-20% and usually the Measuring block shows 101.5%. While on the freeway it was staying pretty steady between 93-95% and sometimes backing off to 101.5%. My question is, do I need to calibrate it so that the veins parameters are going all the way from 0% to 100% or is the 101.5% normal. If someone with a normal car could watch Measuring block 43, 2nd row and let me know how your car reacts under slow acceleration (especially between idle and 2500 RPM) that would be very helpful. I logged the VCDS today if anyone would like to see how it is acting. Also, I will be adjusting the turbo stop screw tomorrow if I can locate some instructions, and I'll post the results.

I would use post #62 above.
Jeff knows what he is doing.

It does not matter if it is 100 or 101. I think mine worked fine (BEW though) over a purposefully misadjusted (just testing) range of -7% to about 107%. It usually maintained about a 95% difference between the top and bottom number. This was not adjusting the stop screw, but the preload (actuator rod length).

When you are adjusting the stop screw that JSRM (Jeff) mentions, you are NOT adjusting it to a particular value on VCDS. Though you can use the VCDS as an indicator of how much motion you have made - I would like to see the data. I would guess that if you were watching it before and after the adjustment ( and before operation - using a vacuum pump) that you would see the max number drop from about 101 to a number that was still over or near 90% - but that is a guess.

For actuator length (preload) I would set it after adjusting the stop screw, you want it to start moving at 3-5" hg, and be on the set screw by about 18". I would probably try to adjust it so that it was nearer the 5"hg to start moving than the 3" to start moving.

Finally Fixed!!!

Well everyone after months and months of troubleshooting (not wanting to throw parts at it to find the problem), the problem is finally fixed!!!! After the turbo adjustment, this car is one smooth running, non-black smoker, non-surging multiple owner TDI!! It is amazing that one little set screw can cause so many problems and relate to so many sensors including the, MAF, N75, ASV, EGR and many of the output tests on Vag Com, VCDS. After the adjustment I haven't seen one puff of Black Smoke and the turbo is very smooth, with smooth acceleration through all RPM ranges, and still produces specified boost as verified in VCDS logging. I would highly recommend adjusting the screw if you are experiencing any of the issues related in this thread.

Now as for the adjustment procedure that I used. I used multiple threads to finally come up with the correct adjustment procedure. Mainly this thread, which explains how to adjust the set screw using VCDS. I also used the explanation in post number 62 above from Jeff "jsrmonster" and the previous post from Dan "DanG144". The procedure that I used is posted below, thanks to O.C.TDI.

O.C.TDI said:

For setting the stop screw... The setting on the bench is only an initial setting, it has to be adjusted on the running car.
This procedure works for the EDC16 cars, NA 2004-2006
Start with the car up to operating temperature.
Use VCDS, Basic Settings channel 011, turn "ON" The car will slowly idle up to 1400 rpm +/-. Now the VNT is in a calibration mode.
Note the boost values when the VNT is fully closed and fully open. You are looking to unjust the to have a 80 millibar difference between off and on.
Adjusting the screw out will increase the boost spread, turning the screw in will reduce boost.
Once you have tuned this check you actuator setting. I would start with the VNT at full stroke around 18" vacuum.
After this you will have to work with your tuner to fine tune the actuator to match up to the duty cycle and logs.
After each adjustment you should rerun the channel 011 Basic Setting so the smart actuator can learn the parameters of the VNT. THis will help the ECU adapt to the actuator faster than just driving around.

O.C.

Click to expand...

I think that in order to adjust this correctly, VCDS, Vag-Com is a must. The set screw is extremely sensitive, to the point that it takes many small 1/8 turns to finally dial in the correct boost change between on and off. I think that I may have turned the set screw in about 1 to 3/4 of a turn for the total adjustment, and I was about 300 mbar differential between off/on N75 cycles in the beginning. After the first adjustment I could tell that I was headed in the right direction.

I don't want to repeat everything that has already been said, but I couldn't find a description of how to do the adjustment, and wanted to post what tools I used in order to adjust the screw. Also I have to give Jnitrofish credit for doing this same thing using zip ties in this thread. After you start adjusting the screw and realize how small the increments are, you will wonder how it was possible to do the same thing with zip ties. Anyways, Below are some pictures of the tools that I used.

You have to access the screw from the bottom of the car. 1rst you have to take the skid plate off. Then look up from just behind the engine up towards the turbo and you will see the set screw. It is bumped up right against the oil line to the turbo, so you will have to use the 10 mm crows foot with a long extension or a few long ones like I did. The 10 mm wrench is for the lock nut, and I used a 3 mm hex socket to turn the stop screw. The tricky part is figuring out how to hold the lock nut while you turn the stop screw. So to do that I used a long flat tipped screwdriver to wedge between the turbo and the lock nut to keep it from turning while I adjusted the stop screw with the 3 mm hex socket on the long extensions. If you can, try to mark the lock nut and the set screw so that you can be precise on your adjustments. The main adjustment will be about 1 turn or less clockwise or tighter on the stop screw, depending on how far off your readings on VCDS are.

Here are some screen captures of the Basic Setting results after the adjustments.

A few problems that I encountered while adjusting it.

One: the set screw wants to turn with the lock nut, solved that by wedging the screwdriver to stop the set screw as explained above.

TWO: make sure that your A/C is turned off or you will get erratic readings and the end result will be wrong. I didn't realize this until over an hour of adjustments.

Other than that, it was pretty straight forward. Your hex size may be different than mine so you may have to experiment with that a bit. I am going to drive it a bit before I try to adjust the actuator arm so that I can get a little bit of data before I start making finer adjustments. But for now the car runs excellent. I can run all of the engine output tests without the car dying, and I can run the basic settings for the EGR without the car dying now. The specs per VCDS are within the parameters all around the sensors that I have checked.

One thing that I have noticed so far is that in VCDS under engine, measuring blocks, number 11 the specified boost vs. actual boost is off by about 150 mbars at idle up to about 2000-2500 RPMs in park or neutral. I can't remember what they were before but right now specified is 999 mbars and actual is around 865 mbars. VCDS says that it should be between 900-1100 on both spec. and actual. Anyone know if that is OK or if I should adjust something to put actual boost at idle closer to specifications?


By the way, a good way to test your vacuum lines and your n75 system all together is to get a vacuum tee and a $3.00 6 foot section of small vacuum hose(same size as the vacuum hose going to the turbo actuator). Cut a small piece of vacuum tubing about 2 inches or so and place it on one end of the tee, put the other end on the turbo vane actuator and put a vacuum gauge or in my case a mityvac on the 6 ft. hose so that you can route it somewhere where you can see it while the engine is running. If everything is working correctly there should be around 20-23 psi of vacuum and as you accelerate the psi will drop depending on how much the ecu and n75 is demanding. The more the acceleration the more the drop towards 0. I believe BEW engines are opposite, or maybe ALH's, either way mine is a BRM. Anyways, saved me from buying an n75 valve, as I thought that was my problem. Also, Autozone rents mityvacs for free upon return.

Anyways, if anyone needs any information or logs of my experience, let me know. And thanks for the info from everyone on this thread from jsrmonster to DanG144 and Jnitrofish. This one had me stumpted, and I refuse to throw cams, n75 valves, turbos, MAF's or any other part that the dealers have been installing to try and fix this problem. I'll post any updates if I decide to tinker with the actuator arm.
Thanks again,
Wade

Sorry about the pictures

Sorry, I didn't realize that the pictures were that big. It took forever to load on my slow Idaho internet.

Another job well done!



I wish vw mechanics would learn the simple stuff and fundamentals like this in their training.

Funny thing is we had a popular turbo rebuilder here not too long ago that didn't understand this simple concept of proper stop screw / vane adjustment. Many popped turbos and headaches were had from this same problem. Lots of folks always try to blame the sw/tune but it it always the hardware giving headaches.

Jeff

Guess I know what my next step is.

Wow, great job sixamskier! A newbie providing this kind of info...sweet. This all makes perfect sense too.

Is there a situation where you would want the vanes closed off? Idle? Are these acting like a wastegate sometimes? If not, why didn't they design the vanes so they could not touch tip to tail and close off completely?

I was assuming this condition for me was due to the extreme hot and humid temps and running the A/C, and have noticed that around 1800 rpm in 1st gear, the boost just slams so much that the tires started sqealing, most noticable after cold start. Been like this for a couple of years, but worse this year. Was always thinking the vane position sensor is bad, but this adjustment sounds like the remedy.

Im glad to read Six's post here but I need a little help. I'm not a super mechanical guy but I'm very good at following directions. My jetta is expierencing similar symptoms so I went ahead and ran the test to see what my boost pressure was.
With it off it came back with 1060.8
When I engaged it, it built all the way up to 1224 but then dropped down to 979.2 where it would pressurize back up to 1224 again. I wasn't sure if that was the normal process, but either way I have a 164mbar delta and am curious is this is my issue.
I understand you want to have a minimum of 80mbar delta, but can you have too much like me at 164?

If yes, can I tweak the screw and make adjustments accordingly?

Quite a few cars will show more than 200 mbar delta, and still run fine.

The control value steps up and down every 10 seconds or so - that is normal.

What does your car do when you do the EGR test (basic settings 003?)

Thanks Dan, I will try to check the EGR test later. Anything I should look for or report back on?

Results are in!

Ok, I ran the EGR test and my results were as follows:
Spec: 8.2-8.8 mg/str
Actual: 330-415 mg/str
100.6%

I have no clue what they mean, so please help me out here.
I ran the test while idling with the temp of the engine at normal operating temp.

I then proceeded to do a log on a quick test drive around the neighborhood while measuring groups 1, 8, and 11 per Jeffs suggestion.

Its a CSV file with a lot of data. I made 4 marks and the last 2 marks are the areas when I feel the turbo lagging and black smoke coming out the exhaust. Whats the best way to share this log? I'll try attaching a screen shot to this post if I can...

dbdubb said:

Ok, I ran the EGR test and my results were as follows:
Spec: 8.2-8.8 mg/str
Actual: 330-415 mg/str
100.6%

Click to expand...

Was this the basic settings 003 test? Did you click the ON button? It should have been changing every 8 seconds or so between NO EGR (about 450 mg/str) and quite a bit of EGR (fresh intake air would drop to about 225 mg/stroke on a healthy well set up engine.)

BRM engines that have a highly restricted exhaust (as from a plugged Catalytic converter or badly set up turbo vanes) will usually die when the test is run. Every once in a while you see a borderline case where the car runs, but barely, and you see air flows down around 120 mg/stroke or less.

Thanks Dan, I never hit GO to start it... Duh.

I just ran it though, the engine didn't stall out. Looks like my readings when the EGR was on appears to be mostly in the high 100's and low 200's. I grabbed a log, would it help if I posted it?

Thanks.

Was your high reading still 430?

There is really little advantage to posting the log - just an eyeball average of low and an eyeball average of high is good enough.

Thanks for the data, yours does not sound too bad. If the turbo vanes were really going tip to tail, your engine would probably die during this test.

Block off the RGR at the bottom inlet to the EGR and leaving the EGR attached and plugged in should work I believe, as I will try it myself. Leaving the EGR plugged in, I hope will give no check engine light. I have a 2006 BRM and it started blowing some black smoke and as it turned out it was the cam at some 160,000 KM's. It did not idle smoothly, would miss it sounded like at idle. The cam was not worn that much, but was on it's way and started giving problems. If let go too long could do so much damage. The water pump plastic also changed to metal and new belt etc also changed at the same time as they were due. The cam and lifters have been changed to a new upgraded cam. It runs so far great, knock on wood !!!!

This will still throw a CEL, and I think impact your "readiness" code. If you do this and leave your EGR and ASV plugged in, your ASV will end up throttling to reach the target air flow - and that does not work that well. If you unplug your EGR, your car will run very well with the EGR flow blocked off, but it will throw a CEL and codes. I have done this for troubleshooting.

The ECU is not only monitoring that the EGR is present and responding, but also that air flows sensed by your MAF are changed the right amount when the EGR operates.

DanG144 So if I had a spare EGR which I do and moved the plug over to it, leaving the other EGR attached to the intake and were to hang the spare say on the fire wall it would still throw a check engine light?? You have tested and tried this all out correct??

Dan, my high when turning EGR on was 245, but the average looks to be somewhere around 180.

Does this mean the issue is not with my turbo but possibly somewhere else?

FXDL,
If you did that (plug a hanging loose spare EGR in), then your ECU will think the EGR is still intact, so it will continue to follow its normal control algorithm.

This has it fully open the EGR, then if specified flow is still not reached (decreased to spec) it will start throttling the intake flapper valve (AntiShudder Valve - ASV). It will throttle the ASV until it reaches the target. This is almost completely shut, and butterfly valves do not control well there. This usually results in periodically shutting flow off completely for short durations - smoke and rough running. It will also tend to wear out and or break the little nylon gears on the operator mechanism of the ASV.

I have never tried this with a spare EGR. I have seen this happen when the operating mechanism of the EGR was no longer attached to the valve, which is essentially the same thing. The EGR operating mechanism looks intact to the ECU, but it does not get the desired flow, and it starts moving the ASV to reach the target. As long as both the EGR and ASV are hooked up electrically, and the target air flow is reached (or seen by the ECU through some means (relays and resistors, MAF twist), you will not get a CEL.

Just pull off your charge air hose and watch the ASV.

If flows do not reach the target for whatever reason, you will get a CEL. So even if you had a spare EGR and a spare ASV hooked up electricaly but not mechanically, you would get a CEL.

Sell your spare EGR and get a tune that deletes the EGR function and block off the EGR for the off-road driving you are obviously doing.

Can I be wrong? Sure. Am I spending 20 minutes typing this (I type very slow) just to mess with you? No, I am not. I am trying to share what I know (or what I think I know) as best I can.

DanG144. Why does the ASV close based on the EGR. I thought the only thing the ASV did was to close on shut down of the diesel to stop any run on [shudder], other wise it is wide open upon start up and stays that way till shut down again. It stays wide open. If it were to close just a little then the air movement vacuum of air from the engine would close it and the engine would stall. It would take a lot of mech., effort to keep it from closing. Why would it control the ASV as there would be no reason to. A diesel is really a large air pump and you do not want to restrict it in any way. They pull the same amount of air in all the time and the fuel is metered only, not the air. So closing the ASV any will cause the engine to run ruff and or stall. As it says AntiShudder and that is what it is for on shut down only was my understanding. Thanks for getting back and have a great day now eh.

You cannot, block off egr without turning off the ASV duty cycle in the tune (they work together - egr opens while asv closes). Car will stumble on take off cuz if this. Hi loads don't demand egr, so it runs ok on full chat (or heavy throttle), just problems at light/part throttle like cruise. Blocking egr without getting tuned will kill fuel economy cuz of this. You can just unplug your ASV/egr and drive it around fine (with faults).

The maf sensor expects change in air flow when egr opens downstream to let in add'l un-metered air. If the maf doesn't see drop in flow w/egr opening, it reports a fault.

Two things happen with all sensors, they first shake hands on boot-up, and they repeatedly go thru calibration/verification during operation. If you unplug it or it fails to function (per spec) you get poor performance, fault lights, and limp mode can occur.

You can easily trick the maf sensor with a device that will attenuate signal during egr cycles, but I call this a de-tuning box. Tricking/reducing metered air flow voltage also reduces fueling! These were sold in the old days for TDI's, but they are currently in use on MB, and Jeep Liberty now too. Get a 2 channel O-scope and watch egr duty cycle, and maf signal play together, and you can build an egr-emulator box real easy. A quick search (tech4tdi) will find you easy instructions to build your own (been there done it).

Jeff

Like I said, try your spare and watch it.

I have already done the best explanation I can.

One thing, the forces on the butterfly valve are fairly well balanced, as it pivots near the center.

The EGR only works at idle does it not only so I thought? You are saying it is controlled and works all the time to screw up our BRM's? The ASV is really also an air throttle you are saying if it closes based on the EGR position .The idea is the ASV closes some what so as to cause more draw from the EGR? The EGR opens and the asv or rather throttle plate closes some what? On the ALH diesels the ASV was just an ASV and did not work with the EGR. Diesels suck big time now. How about blocking off the egr at the tube at the top where it enters the inlet to the EGR and from the inlet of the egr a tube to an air filter which will allow only "clean air" to the intake but at the same time the MAF sensor will see a change in air flow and all will think everything is well and norm.? If not to a air filter then back to intake it self and to the pressure side of it, as if the exhaust gases where still flowing through? I know I am fishing wright? Have a great day now eh..

Responses in bold type are mine.

FXDL said:

The EGR only works at idle does it not only so I thought? It works anytime the engine is not under high load.
You are saying it is controlled and works all the time to screw up our BRM's? It works anytime the engine is not under high load.
The ASV is really also an air throttle you are saying if it closes based on the EGR position . Yes, it is an air throttle. NO, not on EGR position necessarily, but on the difference between the specified and actual air flow, if the EGR valve alone is not enough to produce the desired result.
The idea is the ASV closes some what so as to cause more draw from the EGR? Correct, if this is required to reach the target air flow.
The EGR opens and the asv or rather throttle plate closes some what? Yes, if required.
...How about blocking off the egr at the tube at the top where it enters the inlet to the EGR and from the inlet of the egr a tube to an air filter which will allow only "clean air" to the intake but at the same time the MAF sensor will see a change in air flow and all will think everything is well and norm.? If not to a air filter then back to intake it self and to the pressure side of it, as if the exhaust gases where still flowing through? I know I am fishing wright? Have a great day now eh..
If you would rather have a Rube Goldberg plumbing nightmare controlled by two active valves (and both would have to be moving almost all the time, since the exhaust backpressure is not present to help move the air), than to pay for a tune that is known to have many other benefits, then have a ball. It would work in theory - but it grossly violates the KISS rule.

And you cannot take the pressurized air from the intake - what is being controlled is the fresh air intake that passes through the MAF. The EGR and ASV will throttle until the fresh air flow through the MAF drops to the target value.

Click to expand...

Unsubscribed, eh.