35psi spikes ***

Not sure if this is a performance topic of not. For the last few days I noticed that my golf with slight steady increase in pedal would yield 24-26psi. This is not at full throttle and I wasn't accelerating hard. Yesterday I got a 30psi spike. I call it a spike but its only because I let off the throttle.

To day as I left the gym. In third gear at slight thottle I could maintain 22psi. At this point the engine cut out a few times then went into limp mode. BTW limp mode proved to me that a vnt17 can allow the tdi to operate with less than 1psi. Need to get with Jeff and see if I can get a custom program that will allow for that low boost during normal driving MPG's!!!

The limp mode threw two codes: 17969 - Quantity Adjuster (N146): Control Deviation and 17965 - Charge Pressure Control: Positive Deviation.

EDITED Trouble shooting: cleared the codes. checked all hoses, vnt moves freely, cleaned both check valves, cleaned N75, replaced N75 with N18 (same part #, lengthened vnt rod, adjusted vnt stop for less boost and replaced the black/white check valvle. Took for a test drive. With ease the engine put out enough boost to put the gauge needle at the bottom.. I guess 35psi... I was no were near full thottle. no codes thrown.

---

Also ran the car without the vnt vacuum line connected. No overboost. Lack of power and smoked.

UPDATE-------
Problem solved. I removed the EGR block off plate and stuck a small hose into the exaust manifold. I then sprayed a some seafoam small amounts at a time. I then applied vacuum and worked the VNT. Let this set for about 30mins. Started the car and watched the blue smoke boil out. Boost will jump right up to 22psi then hold.

http://www.seafoamsales.com/deepCreepConsumer.htm http://www.seafoamsales.com/deepCreepTech.htm

I used my old vnt15 as a test. I could see the hose reaching the center hole and sprayed alot of seafoam and NONE reached the exhuast ports. But I do recommend that the car be faced up hill. Let gravity help.

You can also use your n18 valve for the egr valve and swap them for testing purposes.

boostvalve is the same as before. not sure why it isn't helping

VAG logs show me
TIME RPMS IQ mbar mbar
3.85 2289 16.2 1346.4 1377
4.6 2457 23.4 1601.4 1438.2
5.33 3003 49 2519.4 1876.8
6.06 3423 17.6 2519.4 2560.2

so in 1.4 seconds the car went from 23psi to 37psi...

I had a similar problem, i was seeing spikes of 30+ psi. Took off the VNT actuator and cleaned the piss out og it, worked it around for a while, put it back on, and i'm seeing normal levels now (22-25(max)). At WOT it holds at 22-23psi (w/boost valve). Check with boostvalve.com, ask if he'll send you a stiffer spring for the boostvalve, i'm gonna do that just to be safe.

Not sure if this is a performance topic of not. For the last few days I noticed that my golf with slight steady increase in pedal would yield 24-26psi. This is not at full throttle and I wasn't accelerating hard. Yesterday I got a 30psi spike. I call it a spike but its only because I let off the throttle.

To day as I left the gym. In third gear at slight thottle I could maintain 22psi. At this point the engine cut out a few times then went into limp mode. BTW limp mode proved to me that a vnt17 can allow the tdi to operate with less than 1psi. Need to get with Jeff and see if I can get a custom program that will allow for that low boost during normal driving MPG's!!!

The limp mode threw two codes: 17969 - Quantity Adjuster (N146): Control Deviation and 17965 - Charge Pressure Control: Positive Deviation.

Trouble shooting: cleared the codes. checked all hoses, vnt moves, cleaned both check valves. Took for a test drive. With ease the engine put out enough boost to put the gauge needle at the bottom.. I guess 35psi...

I was no were near full thottle. no codes thrown.

Next I need to clean the n75 valve.. unsure if there is a certain method.?? I have a audi TT 1.8t n75 valve, unsure if it will work???

Click to expand...

It sounds like your vanes are stuck closed... and you're using every last bit of exhaust energy to spin the turbo. Since your boost controller doesn't help, it seems like this makes sense.
You said that the VNT moves, but are you sure? Maybe the actuator has become disconnected from the nozzle ring, and it isn't actually moving the vanes. (pure speculation)

Do you have a VAG COM? can you log the MAP and see if the readings jive with your boost gauge?

Is there any way your boost controller could have been hooked up to provide a POSITIVE feedback loop instead of a negative one?

moondawg

It sounds like your vanes are stuck closed... and you're using every last bit of exhaust energy to spin the turbo. Since your boost controller doesn't help, it seems like this makes sense. <font color="blue"> But I can cruise at 65mph with 3-4psi</font>

You said that the VNT moves, but are you sure? Maybe the actuator has become disconnected from the nozzle ring, and it isn't actually moving the vanes. (pure speculation) <font color="blue">Am I sure.. not really </font>

Do you have a VAG COM? can you log the MAP and see if the readings jive with your boost gauge? <font color="blue"> they are posted above</font>

Is there any way your boost controller could have been hooked up to provide a POSITIVE feedback loop instead of a negative one? <font color="blue"> the ball end is toward the VNT and the spring end is toward the N75 its been this way for many months now and not problems</font>

I had a similar problem, i was seeing spikes of 30+ psi. Took off the VNT actuator and cleaned the piss out og it, worked it around for a while,

Click to expand...

Could you tell me how to do this... or is it as easy as you say?

Pulled the n75 and sprayed contact cleaner in all ports. Looked to be clean. The volt meter shows voltage flow of 12.xx volts and ohms of .09.

Not sure what normal resistance is? I tried to use jumpers like you would for a relay but nothing happened. Is it supposed to click?

I hooked up a mightyvac and watched the vnt actuator work. It had full range of motion. I did notice that about 10% down i could hear and feel a click. As if it was hung up. Is that normal.

I bet it is the vanes. I posted a pic of mine, that had carbon bild up on them. They worked sometimes, but would get stuck on the carbon. Go to my gallery to see some pics. You hay have to pull the turbo and clean the surface and the vanes like I did. I didn't really notice it until flooring it. Would have lower boost at cruise, but would jump right up to 35+PSI.

I bet it is the vanes. I posted a pic of mine, that had carbon bild up on them. They worked sometimes, but would get stuck on the carbon. Go to my gallery to see some pics. You hay have to pull the turbo and clean the surface and the vanes like I did. I didn't really notice it until flooring it. Would have lower boost at cruise, but would jump right up to 35+PSI.

I've only had the vnt17 on for less than 10k miles. So if it is carbon build up I'd like to cure the problem and not the effects. Don't want to pull a turbo every 10k miles...

I'll cycle the vnt vanes with the mightvac as many times as I can. Then if that don't work I guess I'll pull the turbo this weekend.

I am starting to hate VW's...... I've worked on this car more than three motorcycles, a jeep, camaro, honda, falcon, and sabb all put together!

I've got a crazy and possibly stupid idea.. How about I remove my egr block off plate and pour some type of cleaner "fuel, b100, seafoam, ???" down the exhaust manifold. At the same time use the mighty vac to work the vanes open and closed.

My only concern might be the fluid working its way to the head. I could use a flexable tube to ensure that fluid is down deep in the manifold.

Suggest this to the guy posting who wants more smoke. My guess would be any carbon hard enough to interfere with the vanes isn't going to just let go in the presence of solvent. You probably won't hurt anything though.

There are spray foam carb cleaners that you are supposed to throw down the throttle body/carb of a gas car while idleing that may do the trick (don't do it with your car running though). A couple or 3 cans of Contact cleaner may get things dissolved a bit, or wd-40 if this is your last resort.

It does sound like a "sticky actuator" to me, since I have had the same disease. Cleaning helps, but there's nothing like a new one

I would not recommend any solvents that leave a residue as they might make the problem worse if they carbonise with heat and there is pleanty of heat down there. Maybe brake cleaner???

There is a web page from some guy in Germany that futzes with old turbos and built a monocopter (flying suit) It's worth a few laughs and he has a great breakdown of the disassembly a lot of huys have found useful in the past.

HTH

VAG logs show me
TIME RPMS IQ mbar mbar
3.85 2289 16.2 1346.4 1377
4.6 2457 23.4 1601.4 1438.2
5.33 3003 49 2519.4 1876.8
6.06 3423 17.6 2519.4 2560.2

so in 1.4 seconds the car went from 23psi to 37psi...

Click to expand...

Just to be sure... you're looking at a gauge and seeing high readings, right? Because vagcom readings are absolute pressure, not boost pressure. 2560 mbar means about 1560 mbar of boost, or about 22 psi boost.

Unless RC "tricks" the ECU so that it can use a 2.5 bar MAP and those readings aren't accurate...

Just to be sure... you're looking at a gauge and seeing high readings, right? Because vagcom readings are absolute pressure, not boost pressure. 2560 mbar means about 1560 mbar of boost, or about 22 psi boost.

Unless RC "tricks" the ECU so that it can use a 2.5 bar MAP and those readings aren't accurate...

Click to expand...

That might be the case with RC. But I have wateched the boost gauge almost complete a circle and return back to zero.

I had posted this on vwvortex in the vagcom section.

When using the output test on vagcom whats supposed to happen on the N75. The EGR solenoid clicks

I was told this "The solenoid valve must operate and the rod for the charge pressure control pressure unit on the turbocharger must move back and forth (at least 3 - 4 times, as long as there is vacuum in the vacuum reservoir).
If the solenoid valve does not operate:

- Check charge pressure control solenoid valve -N75-: "

When I did the output test I never heard or felt the N75 do anything. But I need to watch the ROD and check the vacuum level.


thanks for all the help guys. If not for this web site I would have sold the Golf and got a WRX.

I only had mine on for 10-15k miles when I had a problem. I never checked the vanes before installing the used turbo. My actuator also was not stroking the full lenghth either. By chipping the car and adding extra fuel, it is adding alot more soot in the turbo. It is likely to add to the quicker build up of carbon. I bet it will be fine for a long time once it is cleaned. My turbo looked well used when I got it.

I've been told this "It sounds like the n75 is pulling continuous vaccume. The boostvalve should be clipping the boost by adding pressure to the back side of the vnt actuator to open the vanes to reduce boost. Unhook the vnt control line at the boostvalve tee. You should have little to no boost. If you are getting over 20 psi unhooked, your vanes are closed and actuator is not fully extending to release boost. "

Sure, unhook the line to the actuator and you should have ZERO boost. Do you still have the EGR stuff in place? If not, it only takes 45 minutes to pull the turbo. Messing with all the stuff in the car probably takes more time then just pulling it and making sure there is nothing wrong with it. I can actually get mine out in 30 minutes or less. I have no EGR stuff in the way thought.

That might be the case with RC. But I have wateched the boost gauge almost complete a circle and return back to zero.

[/QUOTE]

Well, i'm now having this probelm again.... I did clean out the actuator, it was ok for like 3 days, now the problem is back with the same rediculous boost readings... I checked the actuator real quick before work today, and its not returning to fully extended mode (you know what i mean). I'm gonna pull the vac line into the actuator and see if i get no boost....If so, its the actuator, if i get redic readings, gotta be the vanes... After i put the turbo in, i had no problems like this for a while with just Up. stage 1, then it started happening, went away. Got RC4, was fine, no crazy spikes, then it came back, went away, and came back now again. The problem either lies with the actuator, or the vanes.... So, how hard is it to clean the vanes????????! I know i can r&r that turbo in about 2 hours, but is it a ***** to get it apart? The software is set to 22psi, so any problem has to be hardware stuff, there would be no reason for the software to do this, cuz the up.1 software was set to like 18psi Max, and i had no probelm there, but after a while, i was seeing these same wacky boost numbers with the up software, so it cannot be software, when things are working right, i get the correct readings for what the software puts out (Weather it be Up1 @ 18psi max, or RC4.x @ 22psi max)...

Just disconnected the vac hose to the VNT acutator. I see like 5psi or so, no 20psi or anything...I think i'll pull the turbo soon and check it all out, i'd be willing to bet its the vanes all clogged up...

with the line disconnected to the actuator, there should be ZERO boost. If not, there is something else wrong.

As for cleaning the vanes, you can bead blast them, or do what I did and just clean them them with diesel purge and a piece of plastic to scrap the carbon off. DOn't use sandpaper or metal objects, as you can sand the coarting off of the metal. It is treated somehow. The turbo comes apart pretty easy, four 10mm head bolts, and the whole thing will come out of the exhaust housing. Be careful removing it as not to nick any blades. Then, the VNT mechanism is held in place by 3 small torx screws. Undo them and lift off the mechanism. Don't losse anything. There are three rollers and pins, and three spacers. Simple, you will see. Look at exhaust housing and see if there is carbon in there and clean it away. Then take your time and clean the vanes and other components. Re-install. Test that everything works.

NOTE: upon reassmbly, there is a little tiny roll pin that lines up the assemply and exhaust housing. You have to line that up for it to fit properly. You will see it when you take it apart.

Thanks for the info!!! I'll tackle this ASAP...I think the actuator still might be jammed up too, but what the hell, it can't hurt to check everything, do it right, don't do it twice, right?

The actuators are the same as the VNT 15, so if you have one, just swap it out. That's what I did. Mine was not working properly either.

Hmm, perhaps that is why these turbos were sold. Bad actuators makes VW (even in germany I guess!) swap out turbos, LOL.

Mine has been running well, but I still run rc3.1 and lubed up the actuator shaft well, and I run about a turn and a half stop screw adjustment (used to do 3 turns- I know a lot of people say its not good, but I can't see how a bit of lag down low is bad!).

Anyhow, fwiw, my vnt15 turbo had crazy 30 psi spikes. I think it was because of the actuator, which moved fine but probably wasnt fast enough to do what it had to do. That would explain why your boostvalve isn't helping!

vagcom output test shows me that on my 03 Jetta the N75 has a nice crisp click and I can hear the vnt working.. It clicks for about 4 clicks then the vacumm drops but the n75 continues to click just not as loud.
Now for the never ending trouble car my 01 golf. The n75 sounds like an old creaking man standing up. The clicking is not as load or strong. though the vnt does move about three times after that the n75 is barley clicking.

This lead me to either a weak electronic n75 or worn out n75 valve. Or the vacumm resovior is loosing pressure to quick.

I would assume that for those who have cleaned the vnt system just allowed for the weak n75 to function. But the n75 is still weak and will get weaker compound that with the vnt getting dirty again.

EDIT It's not the N75. I've swapped the air shut off soleniod and it does the same thing.

Hmm, perhaps that is why these turbos were sold. Bad actuators makes VW (even in germany I guess!) swap out turbos, LOL.

Click to expand...

But for the most part the german ebay turbos work fine for xxxx miles. The problem wasn't as soon as the turbo swap.

Plus other non vnt17 guys have this problem.