Lost Boost Again

[ScottB5]

I think Audrey has lost boot again.

Same as what happened in Le-Man's, no power, foot flat nothing, struggles to get up hills.

I checked hoses and did the Mr Muscle cleaning but never made any difference.

I got VCDS out and checked for error codes.
I god this one,
1 Fault Found:
00575 - Intake Manifold Pressure
17-10 - Control Difference - Intermittent


I can only assume its the VNTs again. Since I was unable to split the turbo down last time, I could not give it a proper clean, just fill up with oven cleaner and hope its ok.

In the off chance its not or there is a better way around this, has any one got any ideas?

I don't really want to fork out for a new turbo but if its needed, then so be it. This turbo is 14 years old and 150k miles.

Any one got any thoughts on getting this one refurbished?

[B5 BIKER]

If you have checked the pipe work, the air mass meter and the n75 I think would be next.
Although I have read on a few other forums that a collapsing cat can cause this code also
Hope you have a bit of luck with this.

[ScottB5]

00575 - Intake Manifold Pressure: Control DifferencePossible Symptoms

• Reduced Power

Possible Causes

• Solenoid Valve for Boost Pressure Control (N75) defective
• Hoses incorrect connected, disconnected, blocked or leaking
• In 1Z/AHU engines, stuck/rusted wastegate or actuator.

Possible Solutions

• Check Solenoid Valve for Boost Pressure Control (N75)
• Check Hoses
• In 1Z/AHU engines, clean rust scale off wastegate/actuator to allow lever to move.

[aragorn]

Have you checked the movement on the VNT actuator is correct?

I believe its fairly obvious if its stuck, as you cant move it by hand.

[ScottB5]

Have you checked the movement on the VNT actuator is correct?

I believe its fairly obvious if its stuck, as you cant move it by hand.

It moved by hand.
Not very much though.

[PAULF]

Sounds like the VNT is stuck. I'd Mr Muscle it again.

Make sure you really pour the stuff in, and leave it for a good couple of hours.

Operate the actuator arm a few time throughout. Use a screwdriver or similar if it's too stiff or hurt fingers will result!

Run Basic Settings 11 afterwards to see it move up and down.

(Once you get your new VCDS lead you can log a run and see what is going on with the N75 v Boost pressure like I did here 2.5TDi Sluggish - scroll down to the end for the graphs and explanation)

[ScottB5]

Sounds like the VNT is stuck. I'd Mr Muscle it again.

Make sure you really pour the stuff in, and leave it for a good couple of hours.

Operate the actuator arm a few time throughout. Use a screwdriver or similar if it's too stiff or hurt fingers will result!

Run Basic Settings 11 afterwards to see it move up and down.

(Once you get your new VCDS lead you can log a run and see what is going on with the N75 v Boost pressure like I did here 2.5TDi Sluggish - scroll down to the end for the graphs and explanation)

Basic settings 11?
which one where?

I need to find a pipe/tubing to get it down there.
The other tubing I got is not small enough.

[ScottB5]

Paul, Never had chance to get out last night.
Laptop was flat and by the time it was charged it was to wet and windy to care. lol

I'll try again tonight.

I put some more oven cleaner down last night but I got a feeling my hose was not long enough.
I got half a tin left, I'll find a longer hose and I'll try again tonight and get some logging happening with VCDS.

[ScottB5]

I'm not sure if this is any related or any chance.

But I blocked off and removed my EGR. If my blocking attempted failed and left a open end, would that effect the Turbo?

Is the valve that use to control the EGR the same as the N75?

[PAULF]

I don't know about the 1.9, but when I did my 2.5s, I didn't bother trying to feed the tube up through the manifold, I unbolted the exhaust and fed it in behind the turbine by going through the blades. It was a lot easier on the V6 - maybe the same for you?

I would think if you removed the valve and blanked off both ends, any leak would give a reduced boost, not an overboost.

If you are going to play about, this is a good write-up for 1.9s VNT TDI turbo: how to adjust actuator & cure boost problems (May be worth adding to your sticky FAQs??)

[ScottB5]

I don't know about the 1.9, but when I did my 2.5s, I didn't bother trying to feed the tube up through the manifold, I unbolted the exhaust and fed it in behind the turbine by going through the blades. It was a lot easier on the V6 - maybe the same for you?

I would think if you removed the valve and blanked off both ends, any leak would give a reduced boost, not an overboost.

If you are going to play about, this is a good write-up for 1.9s VNT TDI turbo: how to adjust actuator & cure boost problems (May be worth adding to your sticky FAQs??)

The leak is really more of a seeping oil.

I'm thinking more of the lines that I blanked off.

This boost problem only happened after a massive clunk in to gear when I was pulling away.
No idea if its linked.
I've had a quick look at hoses but can't really see any thing underneath.
I also went through a massive puddle on Thursday that ripped off my under tray.

I will sit down and read these links.

[ScottB5]

I got a copy of VCDS light that appears to be working for logs but I don't think I'm logging the right things.

I go in to the mess blocks and pick 3 and press the log button.
I picked 003 and 011 and randomly 4 or 10 but I'm not sure which one displays the N75 valve.
Are theses the right blocks or can someone suggest a better block to measure?

I ran 11 to test N75 and watched the actuator rod/arm/shaft move and noticed it would rise and then drop back down straight away.
Here's a video of it.


I assume that's not right. I thought it would stay up for the 10 or so seconds until VCDS changed it and made it go down again?
I pulled the hose off the top of the actuator and shoved my thumb over the end (No idea if this is a good idea or not) and it stayed sucked on to the end of my thumb with out falling off until it was turned off.

If I lost boost I can get away with turning the engine off and back on and its ok, until I try and give it some beans up hill then it will go in to limp with the code.

[PAULF]

Scott,

I used measuring blocks 011, which gave me Engine speed, Specified intake pressure, Actual intake pressure and N75 Duty cycle. I then put it into the graph, as described in the TDI Turbo link.

I also tried adding other parts, like group 010, which had accelerator pedal position sensor, but it wasn't really worth it.
I'm pretty sure that my Basic Settings test was different, but I'll try and have a go tomorrow to check - time and weather dependant.
I thought my one moved to one position and stayed there for 10 seconds, then moved back for 10 seconds etc.

Maybe somebody here can try on a 1.9 to see if yours should hold position on each cycle?

[murdoch]

Scott, been having the same issue with mine for the last year, I have Mr Muscled it a couple of times, which has helped it short term, but the fault always re occurs, which does lead me to believe that the fault lies with the turbo. the vanes must really be full of cr*p, and as they say sh*t sticks to sh*t, so I'm guessing if some dirt is left in there, it wouldn't take long to build back up !
as in my other thread, I'm fitting a recon turbo today from http://yworld.ebay.co.uk/nerings?_trksid=p2047675.l2559, long term I think it's the only option. hope you get it sorted.

[ScottB5]

Scott,

I used measuring blocks 011, which gave me Engine speed, Specified intake pressure, Actual intake pressure and N75 Duty cycle. I then put it into the graph, as described in the TDI Turbo link.

I also tried adding other parts, like group 010, which had accelerator pedal position sensor, but it wasn't really worth it.
I'm pretty sure that my Basic Settings test was different, but I'll try and have a go tomorrow to check - time and weather dependant.
I thought my one moved to one position and stayed there for 10 seconds, then moved back for 10 seconds etc.

Maybe somebody here can try on a 1.9 to see if yours should hold position on each cycle?

My car is going in to the garage tomorrow to get the wheels rotate.
I will ask them about that actuator tester pump thing, see if that helps test the actuator.
I'm going to see if my friend with full VCDS is free on saturday to do some logging runs and see if we can work out a way to do a test in the auto.
4th gear is top gear, I only got 4, so I might need to do it in 3rd but I'll search and see what I can find.

Scott, been having the same issue with mine for the last year, I have Mr Muscled it a couple of times, which has helped it short term, but the fault always re occurs, which does lead me to believe that the fault lies with the turbo. the vanes must really be full of cr*p, and as they say sh*t sticks to sh*t, so I'm guessing if some dirt is left in there, it wouldn't take long to build back up !
as in my other thread, I'm fitting a recon turbo today from http://yworld.ebay.co.uk/nerings?_trksid=p2047675.l2559, long term I think it's the only option. hope you get it sorted.

That's if it is the turbo, looking at that video I did and others on youtube, it don't look right.
I found some where it goes up and it is held there, its also meant to rise up when the car is started but going by the cycle test, I doubt very much it will stay up.
If I get time and the weather is on my side, I might remove the actuator and see how much is in the VNTs manually.
Found another video on youtube that shows nice smooth movement.

Good luck with your turbo and let me know how you get on.

P.S. The link don't work.

[ScottB5]

This fell off yesterday.
This was a new pipe fitted in a July.

These pipes are annoying me.
Any alternatives to rubber?

[PAULF]

Silicone?

[Ste_Nova]

i changed all mine on my passat to silicone, much better

as for the vnt, the movment difference on mine when it was clogged vs overhauled was massive, clunk clunk backwards and forwards on the recon with minimal effort

[ScottB5]

It appears to be that pipe.
It just feel off when I was I was removing the actuator.

The VNT's move really easily, like yours Ste_Nova.

I replaced the pipe and all seems good but I'm getting annoyed at replacing these rubber pipes every 6 months.

Ste_Nove, Where did you get your silicone pipes from?
I'll have to get a set and replace mine.

[tonya4]

try ebay Scott,looks like 4mm,you can get a couple of metres for a couple of quid

tony

[ScottB5]

WooHoo Lost boost again.
******!!

Address 01: Engine Labels: Redir Fail!
Part No: 038 906 018 S
Component: 1,9l R4 EDC G60AG 1621
Coding: 00001
Shop #: WSC 06335
VCID: 2645CBEEC28BC4287B0


1 Fault Found:
00575 - Intake Manifold Pressure
17-10 - Control Difference - Intermittent
Readiness: N/A


The pipes coming off the N75 looks fine, nothing fell off this time when I wiggled and tugged (Still need to buy the silicone hoses).
I ran block 11 and the engine sound changed when the N75 opened and closed. So I assume that's working and the vain.

I don't know any more.
I'm starting to lose patients with it and thinking about buying a new turbo.

[aragorn]

faulty sensor?

If your changing the turbo, get a nice BV43 on there!

[ScottB5]

faulty sensor?

If your changing the turbo, get a nice BV43 on there!

Sensor?
Which one?

[aragorn]

boost?

[ScottB5]

Not sure if this means any thing to any one cause it means nothing to me. lol

[PAULF]

Scott,

I am no expert, and what I do know is self-taught - and we know what the Chinese say about the tutorial quality of a man who teaches himself!

However,

Have a look here VNT TDI turbo: how to adjust actuator & cure boost problems for how the 1.9 graphs should be done, and what they should look like. It will also let you know what your turbo/N75 is doing and what to do if you do get a new one!

The problem with VCDS Scope is I can't adjust the plot values easily to read the figures.

To log the data, you need to do it in 3-4th gear in a manual to 3-4000 RPM. With your auto, I would look to lock the gear in 3rd and try and get 3-4000 revs/60-80MPH. Hit the log button, then convert it to a graph later using Excel.

An overboost into limp mode will show up as a flat line on actual pressure - like your green line on the scope. For the 2.5s, this is 2500 mBar - I'm unsure what is is for yours. The N75 trace should show max dump (which shows opposite numbers to the 2.5, so I only get confused but I think it is a duty cycle of 90%ish ) at the same time. This would indicate you are trying to reduce turbo pressure but it's not working, hence the overboost. The flat line is due to the ECU limiting the fuel, so the engine slows, reducing turbine speed, and hence boost.

Have a look at my graphs/explanation here #25 for an idea of how the overboost looks.

This could be because of blocked vanes, or leaking hoses (again!) preventing the vanes from going to the 'dump' position
Obviously if the boost sensor is reading wrong, this could cause your ECU to have an overboost reaction without an overboost.
It s unlikely to be the rod stop screw or actuator rod length as you have not yet put a reconditioned turbo on.

[aragorn]

On his graph the green line is, i believe, requested boost, and seems to sit around 1 bar.

Actual boost is the yellow line, and is waay down on requested.

IE he's not overboosting at all, its massively underboosting.

Given the way the boost climbs with RPM, i would imagine that suggests the vanes are stuck in their most open position?

[PAULF]

Ahhh, that makes sense. I didn't see it that way Kev.

You should be able to move the actuator up to the stop screw by hand. If it doesn't, that'll be the vanes stuck.
Max boost is at the top of travel, max dump at the bottom. (So with the engine off, you are at max dump. Start up and at idle, you are in the max boost position against the stop)

I would also wonder if an air leak may cause this, either vacuum in the control line to the N75 or actuator. or a pressure leak in the intake system.

I'm assuming graph 1 is slow driving, with 2 and 3 where you tramped the pedal, with your auto changing gear in graph 3 whilst you held the pedal to the floor?

[ScottB5]

Morning lads,

The actuator still moves by hand, by pressure or buy sucking on the rubber hose.

Paul, you right bought the graph but the road I was on was long, flat straight with round shouts every hundred yards or so.

I'll see if the laptop works and I'll try again in a bit.

I got no idea what the Chinese says about self taught.

[aragorn]

Scott,

Does the shaft move like paul describes? IE with engine off it sits against the maximum dump stop, and with the engine running at idle its pulled full travel to maximum boost?

essentially this sounds like with the engine running its not pulling the shaft up to "boost" mode, and leaving it sitting on the "dump" stop. Thus you get no boost and it climbs with RPM.

[ScottB5]

Scott,

Does the shaft move like paul describes? IE with engine off it sits against the maximum dump stop, and with the engine running at idle its pulled full travel to maximum boost?

essentially this sounds like with the engine running its not pulling the shaft up to "boost" mode, and leaving it sitting on the "dump" stop. Thus you get no boost and it climbs with RPM.

No movement at all.

[ScottB5]

Just been out doing some logs and I happen to end up at an American restaurant.
O well, ill sort them out later

[aragorn]

but you can pull it up by hand?

In that case, dodgy N75 or fault in the vaccum pipework or pump then?

[PAULF]

Scott,

'A man who teaches himself has a fool for a Master'

Re the boost, pull the vacuum hose off the N75 inlet, check with the engine running you have vacuum at the hose (Finger test)
If you can, plug the hose direct to the actuator and see if it gets pulled up to the stop screw.
Plug it back to the N75 and pull the hose from the N75 to actuator outlet. Finger test the outlet for vacuum.
This will let you know if it is the N75 or pipework, and shows which pipe!

Note:- If you are a big girl, the finger test might hurt a bit! (Pinch the inlet hose to remove finger)

[ScottB5]

but you can pull it up by hand?

In that case, dodgy N75 or fault in the vaccum pipework or pump then?

I could on Tuesday but not this morning.

Scott,

'A man who teaches himself has a fool for a Master'

Re the boost, pull the vacuum hose off the N75 inlet, check with the engine running you have vacuum at the hose (Finger test)
If you can, plug the hose direct to the actuator and see if it gets pulled up to the stop screw.
Plug it back to the N75 and pull the hose from the N75 to actuator outlet. Finger test the outlet for vacuum.
This will let you know if it is the N75 or pipework, and shows which pipe!

Note:- If you are a big girl, the finger test might hurt a bit! (Pinch the inlet hose to remove finger)

Ahh yeah. Good old Chinese stating the obvious but making it sound wise and thought provoking.


I'll take a look tomorrow at that. No idea which pipe does what on the N75 but I'll shove my body parts on the end and see what happens.

I'm struggling to get my head around this Turbo thing at the moment, I am sorry if its annoying you in any way

[Turbo unit]

Have you removed the c clip and takern the rod off the vnt arm and just moved the arm?? If so did you move it nice and slow if you feel at any point it grabs even a bit this can course limp mode...If the actuator is holding via a mitty vac then its not that..

Also with the vnt system it can brake away but stilll be in take basicly there is a ring with tiny arms connected to a pin and the pin goes into the vanes and they work loose so the ring will move left and right but that vanes stay in 1 place very common.

The VNT system works in the way of a wastegate but use this pressure to spoil the turbo to stop any low down lag!

[ScottB5]

Couple of graphs.







I've popped out this morning and double checked the pipe work and arm movement.
The arm moves fine, I can't feel any clicking or hard sections. No idea what I was trying to move the other day when it would not move.

3 of the pipes coming off the N75 has split ends. Cut them down and reattached.
I'm ordering some silicone pipe today, I'm running out of good pipe and I can't keep having this happening.
That's assuming the pipes are at fault again.
I've not been out yet but I will log again and see what happens.

[Rudidudi]

Out of interest did this get sorted?

[ScottB5]

Out of interest did this get sorted?

ahh yeah. it did
I replaced the rubber pipes with silicone hoses.
That reminds me, I need to do a graph of it working.

[Rudidudi]

ahh yeah. it did
I replaced the rubber pipes with silicone hoses.
That reminds me, I need to do a graph of it working.

Good job

Out of interest what size were the hoses?