A2 Tdi Maf Sensor Problems ?

M

megapup0

Member
Hi has anybody had this experience with there 1.4 TDI 75KW 2001.


Driving along suddenly a loss of power as if turbo has stopped working, everything suggests MAF Sensor, however stop the car turn the ignition on/off and she's good to go immediately?

I can almost predict when it will happen - engine under load lift off the throttle and bingo.

If I keep the revs up it doesent happen.

No mil light - no diagnostic or pending code - havent tried it with the Vagnostics ?

If anyone can help I would appreciate it

Cheers

Gazzer
 
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It could be the MAF, but to make sure, why not disconnect it and run for a couple of days like this.

You won't damage anything and the car will go into a default mode.

The other possibilities are a hose off somewhere or a partially blocked fuel filter.

Cheers,

Mike
 
vag com

Thanks for that,

The Fuel filter has been changed, I will look for a pipe off or split, could you tell me if I had the Vag-com software would I be able to monitor the parameters in real time to decide whats going on

Cheers

Gazzer
 
megapup0 said:
Thanks for that,

The Fuel filter has been changed, I will look for a pipe off or split, could you tell me if I had the Vag-com software would I be able to monitor the parameters in real time to decide whats going on

Cheers

Gazzer
Click to expand...

Yes, you can see exactly what's happening at the MAF, although diagnosis from there isn't always as straightforward as you might think.

Cheers,

Mike
 
Yes - mine does this - everyday before it gets warmed up. I am so used to it I don't even bother pulling in any more - just turn the engine off and re-start while I am driving along.

MAF sensors are a pain in the ***. Recently, my other car (Octavia petrol turbo) was playing up - lumpy idling / poor acceleration. I disconnected the MAF sensor and it flew!! Ran is like this for a month - no issues. Then I fitted a new MAF sensor (and it does not pull as well).

Mike
 
Hi Gazzer,

Maybe some useful info for you in the TDI FAQ:
http://www.tdiclub.com/TDIFAQ/

Although this doc was written for the older 4 cylinder TDI's, many of the problems are the same. There is a list of about 7 things that can cause an intermittent power loss, like we are both experiencing ;).

GA
 
megapup0 said:
Hi has anybody had this experience with there 1.4 TDI 75KW 2001.


Driving along suddenly a loss of power as if turbo has stopped working, everything suggests MAF Sensor, however stop the car turn the ignition on/off and she's good to go immediately?

I can almost predict when it will happen - engine under load lift off the throttle and bingo.

If I keep the revs up it doesent happen.

No mil light - no diagnostic or pending code - havent tried it with the Vagnostics ?

If anyone can help I would appreciate it

Cheers

Gazzer
Click to expand...

Any progress? Have you tried driving with the MAF disconnected?
GA
 
HI

Yes, was o.k. didnt try for long enough because car needed to go for mot, will try again and post results soon. I feel a purchase comming on VAG COM. The data it will give me, will need to be analysed but with a bit of luck its going to be obvious (Ha)


Cheers

Gazzer.
 
Try squirting the MAF with electrical switch cleaner from Maplins, worked great for my A4, I too tried running disconnected and it ran fine, quick spray with this stuff removed all the gunky residue from the film and away it went, just try not to tough any of the exposed MAF element, the spray will do it for you.
Mike
 
tdiman said:
Try squirting the MAF with electrical switch cleaner from Maplins, worked great for my A4, I too tried running disconnected and it ran fine, quick spray with this stuff removed all the gunky residue from the film and away it went, just try not to tough any of the exposed MAF element, the spray will do it for you.
Mike
Click to expand...

Me too, I successfully cleaned the Pierburg MAF on my 1.9 TDI, which ran perfectly after that.

Unfortunately no luck with the Bosch MAF fitted to my A2 1.2 TDI.
The A2 runs identically with or without the MAF connected, which suggests to me that the MAF is not functioning. Cleaning (1/2 can of WD40) made no difference. A2 still goes into snail mode and needs ignition off before returning to normal driving.

Could this be anything other than a faulty MAF?

GA
 
Where is the MAF sensor? I experienced this today going up hill and wondered why the car was dropping off!

A quick stop, engine on/off and back to normal.
 
> Where is the MAF sensor?

In full view, once bonnet removed. Its on a tube leading from the airfilter. Attached should be a photo of one.

GA
 
Gaff said:
> Where is the MAF sensor?

In full view, once bonnet removed. Its on a tube leading from the airfilter. Attached should be a photo of one.

GA
Click to expand...

Gaff - Many thanks - so where do I spray all over it or do I need to pull it apart?
 
You'll need to release the 2 clips and remove the MAF from the intake tube. Once removed, you'll see the black housing inside that holds the hot wire, which is the bit that needs cleaning. Spray the cleaner into this housing until things run clear.

Cheers,

Mike
 
Replaced MAF, no joy

Hi Gazzer and Mike,

I replaced my MAF with an Audi exchange unit. (Would have been cheaper to buy a new one direct from German parts suppliers, via e_bay.de).

Anyway, the 'new' unit did not solve the problem of losing power following brisk acceleration with the engine above 3000 rpm. So either the exchange MAF is faulty too, or more likely, this was never the problem in the first place.

As my car has only done 44000 miles, I'm loathe to conclude that the problem is a clogged turbo (Lukas mentioned this).

Any luck in solving the problem for your cars?

GA
 
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I presume you tried my suggestion of running with the MAF disconnected for a while?

If you are convinced that the new MAF is fine (it probably is), then follow my other suggestions, either a hose that's come adrift, cracked etc or a partially blocked fuel filter.

Cheers,

Mike
 
Hi Mike,

Thanks.

Checked the hoses and could not see any loose or broken.
The fuel filter was changed about 2 weeks ago, same problem before and after.

The error code that is triggered each time:
17965 - Charge Pressure Control: Positive Deviation
P1557 - 35-00 - -

GA
 
Gaff have you checked the air filter?

Mine's now K&N unit - recylcable as well.

Any leaks in the air intake system?

Also have you checked the VTG turbo for stickiness? The vanes get clogged up with soot (like chimneys) if car used on short runs or in eco mode all the time without full throttle useage.

You might have to remove the unit and either get it proffessionally cleaned or buy an exchange unit. Mine clogged up after 85000 miles.
 
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