'96 Passat AAZ lacks turbo boost

[the_old_diver]

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]

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]

Oh Frabjous Day! One less thing to go wrong - thanks Crasher.
OD

[erico]

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]

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]

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]

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]

Here is a slightly different view of the wastegate valve in the closed position, lower right, and the turbo vanes, upper left.
OD

[Adhara]

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]

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