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the_old_diver
19-01-2008, 02:31 PM
I had a replacement AAZ engine fitted a couple of weeks ago and have been driving very gently since then due to a very noisy wheel bearing. I replaced that yesterday and now find that I can't hear the turbo coming in. If it is working, then it is so subtle as to defy detection.

I was just looking under the bonnet and saw that the connecting rod on the turbo (wastegate actuating rod?) wasn't moving when I revved the engine. Making sure that I didn't alter the setting of the lock nuts, I slackened them back one at a time and I found that the lever going into the turbo would move back and forth but the actuating rod could not be manually moved in and out of the bit on the other end. In its "stuck" position, the lever going into the turbo is almost as far to the right (looking at the engine from the front) as it will go.

I also noticed that the shiny 1" dia pipe going into the stainless steel valve (EGR valve?) is getting barely warm.

I was wondering about leaking vacuum hoses but they are covered in cotton braid and difficult to examine.

Can anyone tell me "how much and when" that actuating rod should move, and what is the correct sequence of tests please?

Thanks for your time. OD

the_old_diver
20-01-2008, 04:14 PM
More info - It seems that the vacuum is generated by a pump down near the oil filter and comes through a thin black pipe to port B on a little black device shown in the photo. A yellow pipe then leads away from port A to a tee-piece with one branch going into the EGR diaphragm(?) (stainless steel thing like a flying saucer) and the other branch going to the wastegate actuator(?). On the kitchen table, the resistance across the electrical contacts is 269 ohms and the inner vacuum nipple - the one with the braided pipe removed - is open to the port marked O. Edit - no it's not, it is open to the port on the end of the valve which had it's cover removed when I took the pic. The outer pipe with the braided hose still on is closed off whether sucking or blowing. Guessing that this is an electrically operated vacuum valve I applied 12v to the terminals and nothing happened - no ports opened or closed, no sound and no measurable current drawn. Edit#2 - on tickover the electrical connector to the valve has negligible volts coming through but above about 1500 rpm it jumps to 13.7V

Dear Marge, is this normal?

Oh yes, while I was at it I connected the black vacuum line from the vac pump straight into the tee piece to wastegate actuator and EGR, which immediately warmed up for the first time. I took the car for a trip along the street like this and power was even worse than before, with some grey smoke. Hope this helps someone to understand what is going on. OD

the_old_diver
22-01-2008, 09:38 PM
Another update, dear readers.
The black plastic thing in the photo above doesn't seem to do anything. It seems to be between the vacuum pump and the wastegate actuator and EGR valve, which also don't seem to do anything. Seeing that the wastegate operating lever wasn't as far on one direction as it would go, I altered the locking nuts so it was at one end of it's travel. I now have turbo boost of sorts and can hear a distant Tawny owl under the bonnet. I doubt that the wastegate is opening, but then I rarely rev above 2500 so maybe this doesn't matter and overboost might not be my biggest problem.

Any contributions welcome, and I'll ask a simple Q about the thing in the pic in the General forum since no-one has drifted past here yet.
Cheers, OD

erico
24-01-2008, 12:13 PM
Another update, dear readers.
The black plastic thing in the photo above doesn't seem to do anything. It seems to be between the vacuum pump and the wastegate actuator and EGR valve, which also don't seem to do anything. Seeing that the wastegate operating lever wasn't as far on one direction as it would go, I altered the locking nuts so it was at one end of it's travel. I now have turbo boost of sorts and can hear a distant Tawny owl under the bonnet. I doubt that the wastegate is opening, but then I rarely rev above 2500 so maybe this doesn't matter and overboost might not be my biggest problem.

Any contributions welcome, and I'll ask a simple Q about the thing in the pic in the General forum since no-one has drifted past here yet.
Cheers, OD

Hi,
The manual shows that device as the wastegate bypass regulator valve N75. here is the blurb from the Bentlet repair manual for checking the device. First ting you must do is disconnect the connector of the wastegate bypass regulator valve N75 from the harness connector and go through the following procedure.
Start engine and briefly raise to maximum speed by operating throttlehttp://www.vwaudiforum.co.uk/forum/../../../../../icons/blank.gif
Wastegate Bypass Regulator Valve -N75- operating rod -2- must move http://www.vwaudiforum.co.uk/forum/../../../../../icons/blank.gif
If operating rod does not move:http://www.vwaudiforum.co.uk/forum/../../../../../icons/blank.gif
Check Wastegate Bypass Regulator Valve -N75- lever -1- for ease of movement. If operating rod and lever are corroded together, replace turbocharger.http://www.vwaudiforum.co.uk/forum/../../../../../icons/blank.gif
If operating rod does not move, even though lever is free to move:http://www.vwaudiforum.co.uk/forum/../../../../../icons/blank.gif
Replace wastegate -3-.Bummer that you readjusted the actuating rod length already. You bypassed a preset for the check when you did that.

FYI Here is how to return the position of the rod back to specifications.

Adjust rod length -3- so rod eye will install easily on lever pin -5- (lever lies against stop with no play).
Shorten operating rod 8 full turns from this position.
Tighten lock nut -1-.



edit: BTW is your turbocharger a KKK or Garret model? There was a recall program to replace the KKK models as they had a big tendancy to die due to oil starvation on engine startup at high revs.
Regards,
Eric

the_old_diver
24-01-2008, 12:58 PM
Eric- many many thanks for your post! Where you wrote "disconnect the connector of the wastegate bypass regulator valve N75 from the harness connector" does this mean to disconnect the electrical connector on the N75?
As far as I can see, (difficult, even with a mirror) there are two pipes going into the actuator - that is, the gold coloured cylindrical bit which makes the rod move. One comes from the N75 and the other comes from the body of the turbo through a thicker pipe with a banjo connector on one end. At present the pipe between N75 and actuator seems permanently open to atmosphere via the N75. If the thicker pipe is also a vacuum pipe which acts as an alternative vacuum source, could this vacuum simply bleed away through the open N75?
If you have the time to answer this I would be extremely grateful, but if not thank you very much for pointing me in the right direction to sort the problem.
Cheers, OD
Edit - yes it's a KKK, but would a recall still be valid on a 12 year old car?

PS If anyone out there has a spare Bentley Manual for sale, please PM me.

erico
24-01-2008, 01:41 PM
Eric- many many thanks for your post! Where you wrote "disconnect the connector of the wastegate bypass regulator valve N75 from the harness connector" does this mean to disconnect the electrical connector on the N75?
As far as I can see, (difficult, even with a mirror) there are two pipes going into the actuator - that is, the gold coloured cylindrical bit which makes the rod move. One comes from the N75 and the other comes from the body of the turbo through a thicker pipe with a banjo connector on one end. At present the pipe between N75 and actuator seems permanently open to atmosphere via the N75. If the thicker pipe is also a vacuum pipe which acts as an alternative vacuum source, could this vacuum simply bleed away through the open N75?
If you have the time to answer this I would be extremely grateful, but if not thank you very much for pointing me in the right direction to sort the problem.
Cheers, OD
Edit - yes it's a KKK, but would a recall still be valid on a 12 year old car?

PS If anyone out there has a spare Bentley Manual for sale, please PM me.

1) Yes, disconnect the connector on the N75.

2) @ 12 years? Probably not, but cannot hurt to inquire. There is a group of cars affected here is the group that recall TK affected. Early production year vehicles.
WvW_ _ _3A_TE000001 - WvW_ _ _3A_TE130028

3) The N75 shouldn't be open to the atmosphere. It is an electrically controlled actuator that is sealed when the hose and banjo fitting is in place. Do you mean that you can see an open place on the diaphragm?

4)BTW...do you have a VAG-COM that you can connect to see if the OBD system shows any DTC code?

Have a read of this thread (http://tech.bentleypublishers.com/thread.jspa?threadID=16192&tstart=0&ticket=ST-6120-0ynWCSDVg6WmpZNhFX0Y) at the Bentley Technical discussion forum. It might have some good info for you. It is all about lack of turbo boost!



Regards,
Eric

the_old_diver
25-01-2008, 12:50 AM
OK - I'm confused by the names of things. There are some excellent photos of a turbo like mine in this post - http://www.vwaudiforum.co.uk/forum/showthread.php?t=19945.
The turbine side of the 'charger is rusty steel, the compressor side is aluminium, the actuating rod is clearly visible connecting the wastegate lever on the rusty bit with what I would call the "wastegate actuator" - the yellowish cylindrical bit with two pipes going into it. So far, so good and the N75 "wastegate bypass regulator valve" should be on the other end of the pipe going nowhere in the photos.

I've had a problem with my VAGCOM today - it couldn't find the engine modules, but it did find
Control Module Part Number: 028 906 124 A / Component and/or Version: Turbo-Diesel V01 / Software Coding: 00127 / Work Shop Code: WSC 00000 1 Fault Found:
01265 - Exhaust Gas Recirculation Valve (N18) - 31-00 - Open or Short to Ground

This is confusing me because the EGR valve itself has no electrical connections, and is pneumatically operated by the black solenoid valve in my photo above, which is also connected via a "tee-piece" to the wastegate actuator with the rod coming out of it. So the ECU cannot know what the wastegate actuator is doing, only what it has been signalled to do by the opening of a valve N18 / N75 in the vacuum circuit.

So is the N18 in my VAG-COM the same as other people's N75 - " Wastegate bypass regulator valve" ? Either I'm much thicker than I thought or someone can't write a precise manual, or both :-)

Think I'll go and stroke my cats.....

OD

PS Final thought re wastegate actuator - do both pipes go to the same side of the diaphragm? I can visualise that pipe coming from the compressor output via the banjo nut and feeding positive pressure under the diaphragm, pushing the rod into the actuator and opening the wastegate once a certain boost pressure is achieved...

erico
25-01-2008, 03:19 AM
OK - I'm confused by the names of things. There are some excellent photos of a turbo like mine in this post - http://www.vwaudiforum.co.uk/forum/showthread.php?t=19945.
The turbine side of the 'charger is rusty steel, the compressor side is aluminium, the actuating rod is clearly visible connecting the wastegate lever on the rusty bit with what I would call the "wastegate actuator" - the yellowish cylindrical bit with two pipes going into it. So far, so good and the N75 "wastegate bypass regulator valve" should be on the other end of the pipe going nowhere in the photos.

I've had a problem with my VAGCOM today - it couldn't find the engine modules, but it did find
Control Module Part Number: 028 906 124 A / Component and/or Version: Turbo-Diesel V01 / Software Coding: 00127 / Work Shop Code: WSC 00000 1 Fault Found:
01265 - Exhaust Gas Recirculation Valve (N18) - 31-00 - Open or Short to Ground

This is confusing me because the EGR valve itself has no electrical connections, and is pneumatically operated by the black solenoid valve in my photo above, which is also connected via a "tee-piece" to the wastegate actuator with the rod coming out of it. So the ECU cannot know what the wastegate actuator is doing, only what it has been signalled to do by the opening of a valve N18 / N75 in the vacuum circuit.

So is the N18 in my VAG-COM the same as other people's N75 - " Wastegate bypass regulator valve" ? Either I'm much thicker than I thought or someone can't write a precise manual, or both :-)

Think I'll go and stroke my cats.....

OD

PS Final thought re wastegate actuator - do both pipes go to the same side of the diaphragm? I can visualise that pipe coming from the compressor output via the banjo nut and feeding positive pressure under the diaphragm, pushing the rod into the actuator and opening the wastegate once a certain boost pressure is achieved...

Prior to were running the VAG-COM diagnostic test did you initially clear all the DTCs stored?

Did you have the wastegate regulator valve N75 connected?

The Bentley manual's schematics show both the EGR (Exhaust Gas Recirculation) Vacuum regulator solenoid and the wastegate regulator valve N75 as two seperate devices. The block diagram of the TDI Diesel Electronic control system also shows that, although they appear to be almost identical.

The EGR (Exhaust Gas Recirculation) Vacuum regulator solenoid connector wires are black/yellow and white. The wastegate regulator valve N75 connector wires are black/yellow and brown/blue. This is what the Bentley manual schematic shows for 1995, 1996 and 1997 TDI 1Z engines.

The manual is not as clearly written as it should be. The manual says that (even though one is described)...TDI engines do not have a wastegate. The turbine blades speed is controlled by vanes inside the turbine housing. That is what the Wastegate actuator controls.

Interesting

On your final thoughts... one hose provides negative pressure (upper side of wastegate )and the other hose(bottom side of diaphragm) provides atmospheric pressure. They are on opposite sides of the wastegate diaphragm. So it is the exact opposite to what you were visualizing.

The ECM actuates the Boost Pressure control valve (inside the turbocharger) via the wastegate regulator valve N75 to move the turbine's vanes to a more closed angle to increase boost(higher turbine speed) when the ECM detects increased engine speed.

When the ECM senses lower engine rpms and the vanes are moved to a more closed angle by the wastegate regulator valve N75, reducing exhaust gas pressure and turbine speed, but allowing more exhaust gases to flow and extracting less energy from the exhaust gases.

I just looked at the manuals DTC code chart. a bad EGR vacuum regulator solenoid valve N18 will cause reduced power output and black exhaust.


Regards

the_old_diver
25-01-2008, 11:47 PM
Eric - again many thanks for your help. I cannot make the wastegate actuator move but I will get the turbo off my old engine in the next few days and try to fit that instead.
Prior to were running the VAG-COM diagnostic test did you initially clear all the DTCs stored? Yes.

Did you have the wastegate regulator valve N75 connected? Yes

The Bentley manual's schematics show both the EGR (Exhaust Gas Recirculation) Vacuum regulator solenoid and the wastegate regulator valve N75 as two seperate devices. The block diagram of the TDI Diesel Electronic control system also shows that, although they appear to be almost identical. Bit of confusion here Eric - mine is an AAZ, which isn't a TDI- see picture.

The EGR (Exhaust Gas Recirculation) Vacuum regulator solenoid connector wires are black/yellow and white. The wastegate regulator valve N75 connector wires are black/yellow and brown/blue. This is what the Bentley manual schematic shows for 1995, 1996 and 1997 TDI 1Z engines. I'm still not sure what my solenoid is called*, but the wires are yellow with a black stripe, and brown with a black stripe - could be very dark blue :-) In any case, it doesn't do anything whether connected or not - nothing opens or closes or changes. I had it on the kitchen table this afternoon and tried WD40, 12V, 24V ac and dc and a variety of other torture devices - it just reads 269 ohms and I am going to break it open with a meat cleaver on Tuesday when my new one arrives.

The manual is not as clearly written as it should be. The manual says that (even though one is described)...TDI engines do not have a wastegate. The turbine blades speed is controlled by vanes inside the turbine housing. That is what the Wastegate actuator controls.

Interesting

On your final thoughts... one hose provides negative pressure (upper side of wastegate )and the other hose(bottom side of diaphragm) provides atmospheric pressure. They are on opposite sides of the wastegate diaphragm. So it is the exact opposite to what you were visualizing.
OK - but mine seems to be like the one in the picture I linked to, with the pipe from the turbo compressor side (~+10 psi?) going in below the diaphragm, and the line from the vacuum pump (via N18) going in above the diaphragm. I will get the hang of it one day...
The ECM actuates the Boost Pressure control valve (inside the turbocharger) via the wastegate regulator valve N75 to move the turbine's vanes to a more closed angle to increase boost(higher turbine speed) when the ECM detects increased engine speed.

When the ECM senses lower engine rpms and the vanes are moved to a more closed angle by the wastegate regulator valve N75, reducing exhaust gas pressure and turbine speed, but allowing more exhaust gases to flow and extracting less energy from the exhaust gases.

I just looked at the manuals DTC code chart. a bad EGR vacuum regulator solenoid valve N18 will cause reduced power output and black exhaust. Interesting - but I don't have black exhaust emissions that I have noticed. I'll report back when I have corrected the known defects - N18 and wastegate actuator.

Thanks again, OD

* technically it is a 191 906 283 A

Crasher
26-01-2008, 12:52 AM
It isn't called an N75 valve on the AAZ as the turbo isn't controlled in the same way as a 1Z TDI.

the_old_diver
26-01-2008, 11:32 PM
I took the car for a run today after clearing the fault codes, but the only one I could find afterwards was "01265 - Exhaust Gas Recirculation Valve (N18) - 31-00 - Open or Short to Ground" - which will be the duff N18. I can't seem to access any of the engine modules with VAG-COM - either through "Engine" or "Drivetrain" menus. I can access the Diesel Pump (or is it Fuel Pump?) menu, the Airbag, which has a firing problem and the Immobiliser modules.

Can anyone tell me where the ECU is on this 96 Passat AAZ, and where the connector is in the engine bay?

Finally - what is this connector in the photo and how do you dis-connect it for cleaning please?
Cheers, OD

Crasher
27-01-2008, 03:16 PM
You won't access an AAZ ECU, it doesn’t have one! The only electronics control unit it has is in the injection pump and the glow plug really under the dash. These two units work together under the controller 41 heading.

the_old_diver
27-01-2008, 04:29 PM
Oh Frabjous Day! One less thing to go wrong - thanks Crasher.
OD

erico
27-01-2008, 09:18 PM
I apologize for not reading the thread subject line closely and leading you down what must have been a confusing path. Your motor and its management system is simpler than a TDI's. An AAZ has considerably less electronics(almost none) and does not have a variable vane Turbocharger as part of its fuel induction system.

I can email you the Bentley schematic in PDF format if you would like. It is a small file @119 kb. There really are not that many components to go wrong on your car. There are actually only six components comprising the Engine management system on a AAZ motor. If I were you I would be looking real hard at the N161 two valve for EGR. That one is a strong possibility. Get yourself a can of contact cleaner and spray out every connector you can find that is part of your engine management system.

The turbocharging system on the AAZ motor is purely mechanical. If you are having no-boost problems then your turbo or the wastegate acuator are probably what is wrong. I have a Peugeot 205 Turbo D as a second car. It has next to nothing for electronics. Your motor management system is second generation diesel just like my little reliable (and quick) Peugeot 205. :)

It surprises me that the mechanic couldn't easily sort this out.
BTW in diesel motors the fuel pump is a Diesel pump.

Regards

the_old_diver
27-01-2008, 11:20 PM
Hi Eric,
I'd really appreciate the pdf - I will PM you my email address. I would like to check out all the electrical connectors, which is why I included the photo of the big one at the top of this page - I cannot figure out how it comes apart. Maybe Crasher will tell me " it comes apart with difficulty".

There are actually only six components comprising the Engine management system... would they be reins, bit, stirrups, saddle and girth?

Many thanks again. OD

PS I came across this photo called "Got it going!"

erico
28-01-2008, 12:04 AM
Hi Eric,
I'd really appreciate the pdf - I will PM you my email address. I would like to check out all the electrical connectors, which is why I included the photo of the big one at the top of this page - I cannot figure out how it comes apart. Maybe Crasher will tell me " it comes apart with difficulty".

There are actually only six components comprising the Engine management system... would they be reins, bit, stirrups, saddle and girth?

Many thanks again. OD

PS I came across this photo called "Got it going!"

I don't see the photo on the top of the page. If you are talking about the Large one on the right-hand side of the motor it is pretty easy. Use channel lock pliers ,gently grip it and turn it counter clockwise. Is is extremely difficult to disconnect it by hand. I routinely spray that one out about every six months.

Cool photo. :) I saw something like that in the Dominican Republic and in the Phillipine Islands.

Regards

the_old_diver
07-02-2008, 10:30 PM
For those who haven't seen a KKK turbo wastegate, it looks like this.
This is my take on how it works:
WA is the wastegate actuator, connected by tubes to the positive pressure side of the compressor stage and also via the N18 (aka N161) solenoid valve to the engine vacuum pump. It is connected by the rod to a lever (US levver) on the wastegate valve shaft. When the engine conditions are suitable, a combination of pressure on one side of a diaphragm and vacuum on the other overcomes a strong spring inside the actuator and pulls the rod into the actuator body by about 1/2" / 12mm. This movement of the rod pulls on the wastegate lever and causes the wastegate valve to swing out from its seat, allowing some of the exhaust gases to by-pass the turbo vanes at T, so reducing the boost.

the_old_diver
07-02-2008, 11:06 PM
Here is a slightly different view of the wastegate valve in the closed position, lower right, and the turbo vanes, upper left.
OD

Adhara
19-02-2008, 11:58 PM
this may be relevent, a couple of years ago my 95 AAZ had an intermittent turbo and black smoke. It was caused by a faulty switch on top of the injection pump , not sure what its called but it operates at part throttle. On a light throttle the switch is closed, I dont remember if this is open circuit or not but eather way it controls that air valve and disables the turbo with a vacuum actuator and opens the EGR valve. As soon as you push the throttle past the swtch operating point the EGR closes and the turbo is enabled.
So a temporary cure for me as advised by a diesel specialist was just to disable the system, leaving the EGR valve closed and the turbo always on.
This was achieved by disconnecting the faulty switch and blocking the vacuum pipe that controls the EGR / turbo disable.

josedebanne
05-04-2008, 02:23 PM
Hi Erico , i have an Golf MK3 GTD , AAZ Engine. When i buy the car , it have disconected both vacuum valve , ( IDLE and WASTEGATE) . I´m not shure what colour cables are for them.
You can email me schematic?
Regards

erico
05-04-2008, 06:50 PM
Hi Erico , i have an Golf MK3 GTD , AAZ Engine. When i buy the car , it have disconected both vacuum valve , ( IDLE and WASTEGATE) . I´m not shure what colour cables are for them.
You can email me schematic?
Regards
Hi.
Post a jpg photo of exactly what you are talking about.

You should probably start your own thread. Hijacking a thread is not exactly proper forum protocol.

They are probably disconnected because the system does not work as it should...(i.e bad wastegate or EGR or dead turbocharger).

Does the turbocharger even spool up?

Idle adjustment is done at the diesel injection pump.

On the AAZ turbo...which one do you have? is it the KKK or the Garrett?

I will wait for the photo.

cheers,
Eric

erico
05-04-2008, 07:57 PM
this may be relevent, a couple of years ago my 95 AAZ had an intermittent turbo and black smoke. It was caused by a faulty switch on top of the injection pump , not sure what its called but it operates at part throttle. On a light throttle the switch is closed, I dont remember if this is open circuit or not but eather way it controls that air valve and disables the turbo with a vacuum actuator and opens the EGR valve. As soon as you push the throttle past the swtch operating point the EGR closes and the turbo is enabled.
So a temporary cure for me as advised by a diesel specialist was just to disable the system, leaving the EGR valve closed and the turbo always on.
This was achieved by disconnecting the faulty switch and blocking the vacuum pipe that controls the EGR / turbo disable.

The switch is called an EGR Part Throttle Switch.

cheers,
Eric

josedebanne
06-04-2008, 02:58 AM
Sorry , is my first post , don´t know exactly to do this.

The turbocharger appears to work well
The turbo is KKK

Both valves are disconnected and the exactly question is what colours of cables are for wich valve , One connector have colours Brown/Black - Black/Yellow. The other has Blue/Red - Black/White.

Crasher
06-04-2008, 11:56 AM
What is the vehicle? It looks like an AAZ engine but car and year would help.

erico
06-04-2008, 12:59 PM
Sorry , is my first post , don´t know exactly to do this.

The turbocharger appears to work well
The turbo is KKK

Both valves are disconnected and the exactly question is what colours of cables are for wich valve , One connector have colours Brown/Black - Black/Yellow. The other has Blue/Red - Black/White. I can only make an educated suggestion for you. Your car uses a different wiring configuration than the Passat TDI.

Here is how the 1996 Passatt sedan and variant is set up according to the schematics:

Wastegate Bypass Regulator Valve: Black/Yellow and Brown/Blue

EGR Vacuum regulator solenoid N18 : Black/Yellow and White

So..chances are that the on your car the Blue/Red and Black/white connector is for the EGR Vacuum Regulator solenoid.

The other connector should be for the Wastegate Bypass Regulator Valve on your Turbocharger.

best I can do for you without having the actual manual. What year is your car? You really should have posted this in the Golf TDI section.

josedebanne
06-04-2008, 01:14 PM
It's an VW GOLF GTD 1998. AAZ Engine. Made in Mexico
I will search in Golf TDI Section.
Thanks Erico.

erico
06-04-2008, 01:53 PM
It's an VW GOLF GTD 1998. AAZ Engine. Made in Mexico
I will search in Golf TDI Section.
Thanks Erico.

You are quite welcome

Regards,
Erico

the_old_diver
11-04-2008, 09:54 PM
Hi there,
Sorry this is late but it might help: My '96 Passat TD has an AAZ engine and only one solenoid which activates (= "supplies vacuum") to both the EGR valve and the Wastegate actuator. The solenoid is officially an N18, and has yellow/black and brown/? other dark colour going to the connector on the solenoid.
Cheers, OD