"Coughin'" TDI90

[Maso]

The issue started as the car was cold but now days its there mostly all the time no matter climate outside or engine temp.

What happens is that if one does push the gaspedal hard to accelerate its does small coughs & looses power/acceleration, the coughs are small but several and they stop once you stop accelerating hard.

Another thing i noticed is that when im crusing at a steady speed with a steady throttle it makes small swayings and by jumps i mean is that it gives engine its expected steady power but for a second it looses it to a second later get it back, this makes for a soft back & forward swaying, it goes into a back and forward swing due to the continously tiny powerlosses.

Had faulty code reader connected to it a work shop but not codes were read out.

The mechanic cleaned a hose that have a thing in it which I think is air flow mass system. When cleaned this the car went really nice for a few days but it started again.

Any thoughts guys? Something that is common and you recognize?

So my thought is that its mechanical and not electrical and that its this air flow mass thingy that either needs a proper cleaning or just a new.

 

[timmus]

It sounds to me like you need a new fuel filter.

Tom

 

[MikeMarsUK]

... The mechanic cleaned a hose that have a thing in it which I think is air flow mass system. When cleaned this the car went really nice for a few days but it started again. ...

Sounds like the mechanic was talking about the MAF / Mass air flow sensor. This measures the amount of air getting through the air filter & hence available for combustion. But what you are describing does not sound like an issue caused by a bad MAF?

 

[Maso]

It sounds to me like you need a new fuel filter.

Tom

Cheers Tom. Will replace the fuel filter to start with. Will get back to you if its all better after the replacement.

 

[Maso]

Sounds like the mechanic was talking about the MAF / Mass air flow sensor. This measures the amount of air getting through the air filter & hence available for combustion. But what you are describing does not sound like an issue caused by a bad MAF?

I agree as well. Been told just like Tom said to change my fuel filter and since i saw Tom mention it i'll go for that as first move, never bad to change a fuel filter anyways.

My regular nechanic is on vacation so im stuck to mechanics whom dont trust so there for i posted my issue. Snd it seems we could have a answer to my problem as Tom aint the first who told me that a fuel filter might be the problem in question.

Will keep you posted and thanx for the feedback guys.

 

[Ole-dk]

I had a similar problem a week ago. Checked with my rostech vcds . No faultcode. Then checked turbo pressure (on the run, full throttle i 3'rd from 2800 to 3200 rpm). It was jumping a bit. Then I suddenly had total los of turbopressure , almost no power , idle fine. Now my VSDC showed an error: Loss off charge pressure, but not until it was completely gone.
Then I Found a hole in the side of the connection pipe to the charge air cooler, see attached picture, marked with red.
This Pipe has a bend down very close to the alternator pulley. and the pulley can grind a hole in it.

I ducktaped it and had pressure again, and smooth running, my vcds showed pressure very close to the specifications.
I ordered a new connection pipe, and moutned it this weekend. and now evrything is fine.

I can not say, that Your problem is the same, but symptoms is similar, and I ended up with e very simple problem. But the connection pipe is very expensive (at least in DK, 600,- dkr aprox 60 £)

 

[Maso]

I had a similar problem a week ago. Checked with my rostech vcds . No faultcode. Then checked turbo pressure (on the run, full throttle i 3'rd from 2800 to 3200 rpm). It was jumping a bit. Then I suddenly had total los of turbopressure , almost no power , idle fine. Now my VSDC showed an error: Loss off charge pressure, but not until it was completely gone.
Then I Found a hole in the side of the connection pipe to the charge air cooler, see attached picture, marked with red.
This Pipe has a bend down very close to the alternator pulley. and the pulley can grind a hole in it.
View attachment 11981
I ducktaped it and had pressure again, and smooth running, my vcds showed pressure very close to the specifications.
I ordered a new connection pipe, and moutned it this weekend. and now evrything is fine.

I can not say, that Your problem is the same, but symptoms is similar, and I ended up with e very simple problem. But the connection pipe is very expensive (at least in DK, 600,- dkr aprox 60 £)

Alright. Will ask the mechanic to have a look around the pipe for holes first before assuming the fuel filter. Cheaper at least to look before changing a fuelfilter.
How far has you TDI km wise gone?

 

[Ole-dk]

Hello Maso

My tdi90 has 154000 km ón the clock.

Hope You Will get Your problem solved soon. Good luck

 

[Maso]

Hello Maso

My tdi90 has 154000 km ón the clock.

Hope You Will get Your problem solved soon. Good luck

Thank you very much. Ok, could very much be the same problem as min has done 143000km.

 

[Maso]

Couldnt find any whole in any hoses so went with changing the fuelfilter and the car goes once again like a dream. Thank you all for the feedback.

 

[timmus]

Excellent!

 

[A2K]

Dr Tom to the rescue!

 

[Maso]

Dr Tom to the rescue!

Weird how such a easy fix can solve such royal pain in the ass of a ride irretation. Payed around £59 for the fuelfilter. Now I can tick that box.

Once again fellas, thanks and what a great start of the weekend huh.

 

[timmus]

I've known a few A2s to suffer from misfire-like symptoms due to the fuel filter being old and clogged.

Tom

 

[Maso]

I've known a few A2s to suffer from misfire-like symptoms due to the fuel filter being old and clogged.

Tom

What would one say that a general rule is to how often one should change the fuelfilter?

 

[timmus]

What would one say that a general rule is to how often one should change the fuelfilter?

I service my car every 10,000 miles and change the fuel filter with every 3rd service.

Tom

 

[Maso]

Okey, cheers. Will make a note of it in my car journal that is has been changed now.

 

[vintage65]

Just thought I'd add my experience to the thread. Had a dealer service recently in Harrogate and after picking the car up it felt under powered. Had a problem with hot starting as well and after a run on the motorway I noticed drips of diesel in front of the nearside wheel. The dealer was excellent and replaced the fuel filter and the housing which can crack on changing the filter. No problems with performance now.
May explain why fuel filter changes can result in poor performance which doesnt come up on diagnostics.

 

[Maso]

Just thought I'd add my experience to the thread. Had a dealer service recently in Harrogate and after picking the car up it felt under powered. Had a problem with hot starting as well and after a run on the motorway I noticed drips of diesel in front of the nearside wheel. The dealer was excellent and replaced the fuel filter and the housing which can crack on changing the filter. No problems with performance now.
May explain why fuel filter changes can result in poor performance which doesnt come up on diagnostics.

Great feedback!