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A6 C5 vacuum stuff


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#1 Brendan68

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Posted 06 July 2010 - 07:28 AM

My engine code is ALT. Which seems to be not very common.

Posted Image

 

There is some sort of a valve on the valve cover, which I believe to be a vacuum activated breather valve or something. It's removed in the photo.

Here is the thing itself: (06B 103 235E)

Posted Image

I can't find any info on this. What I do know is that mine is full of oily gunk and is clearly broken inside. If it wasn't broken before, it is broken now because I was messing with it. [:o]

Anyway it has four ports, one to the valve cover, one to the air intake (after the MAF) one to a plastic bottle which I thing is a vacuum reservoir, and one to the vacuum source ( circled in this photo which I think is a suction pump but again I can find no info on this exact part, 06B 133 753C

Posted Image

Also, the pipe between this valve thingy and the suction pump is full of oily crud.

The connections to the air intake and the vacuum bottle are both sheared off.

So, what got me looking at this area is a DTC I keep getting. I have 2 scanners(both cheapies)

Scanner 1 is giving me 17544 - Long Term Fuel Trim Add.Fuel,Bank1 System too Lean

Scanner 2 is giving me P0171 - Fuel Trim,Bank1 System too Lean

I erased the code on Saturday morning, but prior to that, I noticed the Long Term FT was zero, indicating the car was operating in Open Loop. I checked the LTFT yesterday and it was -12.5

The MAF looks OK, reading about 2.5-4 g/s in idle, depending on engine temp.

I would appreciate any input on what these bits are/do and if I'm on the right track regarding the DTC above.

Brendan.

 

 



#2 leach76

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Posted 06 July 2010 - 08:54 AM

 Isnt the pipe that it goes too that comes out of the bulkhead a water pipe though ? as normally pipes that go through the bulkhead are either air con or water to heater matrix? i have no idea what could be causing the 2 faults but unless anyone shouts an imediate response to those codes i would have it read by a proper diagnostic setup as with diesel engines the cheaper ones throw up codes for things the vehicles dont even have.


 


or if you put the fault codes and descriptions in to google it leads to other peoples faults and diagnostics,even some from this ones sister site:


http://uk-mkivs.net/...873/595997.aspx


http://www.google.co...ql=&oq=&gs_rfai=


But dont know how useful these will be,but if no good there are some good lads on here who i am confident might be able to help or point you to somewhere with more info


 


6fb167b1-cb05-408b-b2d8-a7d22c9be06d_zps

I must confess i was born at a very early age


#3 Brendan68

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Posted 06 July 2010 - 09:14 AM

Hi Leach,

That pipe going into the bulkhead is the master brake cylinder vacuum line. The cylinder is behind that bulkhead on the drivers side, along with the brake fluid reservoir and battery.

I plugged the line from the suction pump to the valve cover breather thingy and drove about 5 miles. The LTFT is down to -7.5 from -12.5 last night.

I'm half sure this is my problem, but without understanding exactly what's going on with these yokes I suppose I can't be fully sure.

I think I need to replace these bits and bobs anyway, as they are full of crud and broken, then re-check the fuel trims again before doing anything else.


PS. Thanks for the links. One of them mentions checking for a leak between MAF and manifold.

http://www.ilexa.co....05798#msg105798

As it happens, because I have a broken breather pipe, air would be getting into the manifold without being measured by the MAF, which couldn't be good.



#4 leach76

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Posted 06 July 2010 - 10:05 AM

 Dont really understand the vacuum advance on cars neither as its seems a system made to go wrong,i think they had something same with vauxhalls where the brake master cylinder vacuum faults caused crap running and powerless problems,and sorry made out it was brake cylinder vacuum after i had posted


6fb167b1-cb05-408b-b2d8-a7d22c9be06d_zps

I must confess i was born at a very early age


#5 Brendan68

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Posted 08 July 2010 - 05:04 AM

After another 50 miles or so, my LONGFT has gone all the way back to zero and settled on +0.8%


To me this is confirmation that the cause of my problem was primarily the unmeasured air getting into the manifold at the broken breather pipe set-up, by-passing the MAF.


 



#6 stevee

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Posted 08 July 2010 - 10:32 AM

 It should run alot better now!


Audi A4 B6 Tdi

Skoda Octavia "down and out"


#7 Brendan68

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Posted 08 July 2010 - 12:57 PM

It is driving a lot better Stevee, Idle RPM is very smooth and the dragging feeling is gone.


The two parts above were not gettable through the usual autoshops so I had to go to the dealer - he's only 10 minutes from the house. Picking them up tomorrow.


06B 103 235E (Dealer only has 06B 103 235G) hope it's the same.


06B 133 753C


Also getting the gasket kit tomorrow.



#8 stevee

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Posted 08 July 2010 - 01:01 PM

Often it's just a newer version of an older part.

Audi A4 B6 Tdi

Skoda Octavia "down and out"


#9 Brendan68

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Posted 09 July 2010 - 09:34 AM

Got new bits for this job also.


06B 103 235 G


06B 133 753 C


06B 103 211 H


This is the breather valve thingy. Cost me €8.53 ex VAT at the dealer.



This is the suction pump thingy. Cost €24.26 Ex VAT.



And this is the breather tube thingy. Cost €38.84 Ex VAT



 


They really do put the funniest of widgets in cars these days.



#10 donachi2000

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Posted 18 January 2012 - 06:38 AM

Hi Brendan, where did you get the above parts from, i need the same too..






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