TDi 90 info required

AndyP

Member
United-Kingdom
Is there anyone with a TDi 90 who can help with with identifying the correct vacuum pipe connections out of the vacuum/solenoid control unit (or whatever it's called)? The one in the car I have has clearly been replaced after the accident (a breaker has written Polo/2003 on the rear - the part number seems correct).

I have a problem with the boost sensor reporting results that are inconsistent with what is expected and basically I don't trust that the vacuum pipes are installed correctly. So photos, diagrams and/or descriptions would all be very welcome.

Thanks
 
Not sure if it's possible to trace the pipes from a schematic but this may help -

Cheers Spike

Oops. Cut and pasted the wrong diagm. I know it's not too useful but have added the ATL / BHC vacuum arrangement for completeness
 

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LOL - yeah I have that diagram, that's why I need pictures !!!!

I'm not sure the numbering of the pipes that comes out of the box are that clear, that's why I want to trace each one on a correctly working car.

Thanks though.
 
I have the same schematic, it worked fine for me. the three solenoids are clearly distinguishable between them. it may help if you colour code the pipes on the diagram.
you will need to remove the cabin air intake to gain access thou.
 
LOL - yeah I have that diagram, that's why I need pictures !!!!

I have the same schematic, it worked fine for me. the three solenoids are clearly distinguishable between them.

Hi folks,

The schematic above is for the AMF engine. The AMF engine has the three solenoids as separate items (one for the turbo wastegate, one for the EGR valve and one for the anti-shudder valve). On right-hand-drive A2s, they're mounted at the back of the engine bay, behind the coolant expansion tank.
Unfortunately, this discussion has ended up divided across two different threads. See here: http://www.a2oc.net/forum/showthread.php?32630-Mini-project-2004-TDi-90
The BHC and ATL engines group these solenoids into a single black box, making the engine bay appear neater but opening the doors to a world of confusion in the process.

Cheers,

Tom
 
I can take some pics of my Tdi 90 if you specify your needs!

Thanks for the offer, (is an LHD any different?) I think what I really need to do is draw up a diagram of all the pipes from the connector, so that someone can fill in the destination of each - unless someone around Essex/Herts way has a TDi 90 that I can look at for myself.
 
Lets start to identify the destinations. Upper row 1 to 4 (left to right), lower row 5-7.
ATL Injection Controller.JPG

  1. connected to crankcase ventilation.
  2. connected to air inlet, between the MAF sensor and the air filter.
  3. connected to a vacuum unit on the intake, see diagram 2, component #1.
  4. does not exist.
  5. dissapear in a black pipe, possible to the diesel tank.
  6. not used, plug inserted.
  7. connected to the brake booster.

ATL Vacuum unit.JPG
 
Lets start to identify the destinations. Upper row 1 to 4 (left to right), lower row 5-7.
View attachment 28410

  1. connected to crankcase ventilation.
  2. connected to air inlet, between the MAF sensor and the air filter.
  3. connected to a vacuum unit on the intake, see diagram 2, component #1.
  4. does not exist.
  5. dissapear in a black pipe, possible to the diesel tank.
  6. not used, plug inserted.
  7. connected to the brake booster.

View attachment 28412

Good info, Steaman. :)

On UK cars the air intake comes from the opposite direction.

Cheers,

Tom
 
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Now that is just what I need - Thanks! I need to check the numbers, but I have a feeling that 4 and 6 might be looped on mine (I know at least one pair is) - that could explain a lot ....

Thanks again.
 
Good info, Steaman. :)

The second diagram, showing the engine bay, does not apply to UK cars because the air intake comes from the opposite direction. Also, the TDI90 uses an electronic anti-shudder valve, so component 1 on the diagram does not exist or need a pneumatic line.

Cheers,

Tom


The vacuum unit connected to connection #3 exist on my Tdi 90 (ATL) 2004.

Trust the map or reality, that's the question. :confused:
 
The vacuum unit connected to connection #3 exist on my Tdi 90 (ATL) 2004.

You're absolutely right. My apologies. The EGR system is the same, but the anti-shudder is different. I just had a bit of visual confusion when looking at the diagram you posted.

Cheers,

Tom
 
Lets start to identify the destinations. Upper row 1 to 4 (left to right), lower row 5-7.
View attachment 28410

  1. connected to crankcase ventilation.
  2. connected to air inlet, between the MAF sensor and the air filter.
  3. connected to a vacuum unit on the intake, see diagram 2, component #1.
  4. does not exist.
  5. dissapear in a black pipe, possible to the diesel tank.
  6. not used, plug inserted.
  7. connected to the brake booster.

View attachment 28412

Well, using your numbering scheme, mine seems to be a very different story!

  1. Connected to a vacuum unit on the intake
  2. Connected to air inlet, between the MAF sensor and the air filter
  3. Disappears down the back of engine (crankcase breather?)
  4. Disappears into the inner wing (Diesel tank?)
  5. Connected to the brake booster
  6. Linked to 7
  7. Linked to 6
I haven't really thought through the impact of these variations yet, I'll need to compare the schematic etc., but I can see how this could easily confuse the ECU without actually preventing it from running.
 
Verified! The only uncertainty is number 1.


  1. connected to ? Could be crankcase ventilation or charge pressure control (turbo).The hose dissapear behind the engine below the intake manifold
  2. connected to air inlet, between the MAF sensor and the air filter.
  3. connected to a vacuum unit on the intake, see diagram 2, component #1.
  4. does not exist.
  5. dissapear in a black pipe, possible to the diesel tank.
  6. not used, plug inserted.
  7. connected to the brake booster.
 
Any chance of a second opinion/source of information for this, as mine is significantly different from steaman?
Thanks in advance.
 
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