Audi A4 B7 2.0 TDi coughing and spluttering again

[chrisp]

Hi,

I own a 2008 B7 2.0TDi 170 S-Line SE quattro avant with 77k on the clock and it's not running too good. This may not be relevant, but a couple of months ago I had the timing belt replaced at 75k and it also had injectors replaced under a recall (main dealer did the work). A couple of days after the work it started juddering under acceleration at about 3k revs but could live with it as try to drive it economically whenever possible. But the problem has slowly worsened, appearing lower down the rev scale, and today it alarmingly refused to go over about 1k revs when I pulled out onto my main road. There are no warnings coming up on the dash but I've booked it into the dealer for Friday.

The car has been dogged by these kind of problems since I bought it new. I've had gas and exhaust pressure sensors replaced after repeated power failures but warning lights came up on the dash for these issues and this time there's nothing.

I've checked through my service history and it doesn't look like the fuel filter has ever been replaced. The car does seem sensitive to fuel (I've got a local indie garage and the the car seems to run worse if I fill up with diesel from there compared to a big name station) so I'm wondering if it sounds like a fuel supply issue?

Any thoughts? If it sounds like a filter problem I might do it myself but realise it could be a multitude of things.

 

[chrisp]

After a bit of rummaging through the forums it seems this is a common problem. Top contenders so far:

1. The MAF need to be checked / cleaned / replaced if necessary
2. The EGR need to be thoroughly cleaned or blanked off
3. The turbo needs to be cleaned - Mr Muscle apparently has the cure

Might try unplugging the MAF first to see if that's the problem.

 

[chrisp]

Quick update. I've had a look under the hood after seeing an egr removal guide on here that helped me identify what's where and made a few discoveries.

Firstly, the EGR valve is showing clear signs of an oil leak, and there appears to be a loop of soft rubber seal actually hanging out of it precisely where the oil is leaking. I managed to get my phone down the back of it to take this pic but it doesn't show up very well. The rubber loop is circled in yellow but shown from the side.

Secondly, the coolant tank level is well over the Max mark on the side. Any idea if this is bad/ok? Excuse another crap photo...

I hasten to add it's only ever been looked at by a main dealer. Was going to take the EGR off and clean it down and replace if necessary but this looks like it could be a bodge, or is this just what happens if they blow?
Any thoughts more than welcome....

 

[chrisk1700]

the rubber loop is normal, dont ask me why but it just is cos mines exactly the same. take the egr off and check if its carboned up and also check that the flap moves on the motor, and not independantly on the shaft. also take the casing off the motor and check the teeth on the plastic cog aint sheered.

 

[chrisp]

Cheers chrisk, that's v. useful info. I was wondering if that was the case with the loop as it doesn't look pinched. Am about to call the main dealer to get the gaskets then hopefully I can limp up there and get them, along with some new torx spanners! Was going to do the journey in my other motor, a faithful old A4 2.8q, but the engine popped last night! When it rains etc...

 

[chrisp]

Ok, got the gaskets from Tonbridge Audi - very helpful bloke called Nick in spares made sure I got the bits I needed. The rubber one is for the join where the anti-shudder valve joins the EGR and it looked like the old one was blowing so thought it best to get that too.

Bought some torx bits but in all honesty the allen keys would have done the job as all the bolts came off easily. Had to use an allen key on one of them though as there wasn't enough room for the torx bit and ratchet.

Finally got the thing off and it was very coked up, especially around the valve - so much so you couldn't even see it, there was just a wall of soot.

And here's the other side...

Got it all cleaned up...

And then took off the black plastic moulding to check the gearing for damage and to see that it still worked. All was fine... here's the mechanism...

I'm turning the white cog here (out of shot) and you can see the valve has turned.

Pieced it all back together and the upshot is I've got 80% of the power back - it was virtually undriveable beforehand so feeling well chuffed. Clearly still got some work to do to get it back up to full revs - going to try replacing all the filters next and if that doesn't do it I might reach for the Mr Muscle.

 

[chrisk1700]

was the flap seized solid with coke???? mine was but not had chance to drive it yet really cos no injectors lol.

also just to bear in mind, the pipe for the egr will have a lining of coke build up and so will the inlet manifold, its not fully cleanable without new parts so what you have done is about as much as you can do.

 

[chrisp]

I'm not sure it was - you can see a slight edge on the valve in one of the pics which might suggest it was still turning. As the cogs were ok I guess this suggests it was still turning although there could be a safety mechanism built in with the spring.

The exhaust pipe to the egr was pretty sooty as far as I could see down it so I cleaned it out as much as I could. I also scraped out as much of the crap as I could from within the inlet manifold - it was quite a lot, but most of it seemed to be near the entry hole although, as you say, without taking it off it's impossible to know what truly lies within!

 

[chrisp]

Quick update on this one.

Performance slowly improved and then I stuck a can of BG244 in it to flush out the system. It got slightly worse before it got better, but once the tank had drained through it started driving like a brand new car.

Typically though, the moment it gets back to normal, the glow plug symbol lit up on the dash, which went away for a couple of days but today it returned - along with the light for the emission control system.

It's booked in with the main dealers for a service but I'll be getting shot asap - it's been one problem after another.

 

[chrisp]

Another update. Back from the main dealers after a Major Service. The glow plug light went off and stayed off prior to the visit, but the emission control system light stayed on and the cause, via VAGcom readings, has been put down to the other achilles heal in this engine - the Intake Manifold Flap V157. Since cleaning the EGR valve and flushing the system with the BG244 the car has been running perfectly and like a rocket (best performance I've ever had out of it) but the engine does shudder when turned off, which is a sign that the IMF is either sticking or knackered.

Having read the excellent thread about IMF problems, there doesn't seem to be an answer as to whether or not running the engine with a faulty IMF does any harm, but I chose not to get the main dealers to change it - the main reason being cost. Their quote: £842.50 !!!!!!! Having removed the EGR and the IMF already (they're bolted together) and knowing what was involved to do the job, I was staggered to say the least.

Murray's Direct have sent me an email this morning - "A brand new latest-spec genuine OEM [Siemens-VDO] unit is £182.50 (plus vat) plus £8.45 shipping. We currently have stock available for immediate [Monday] despatch."

I'm getting costs in from elsewhere but I'll clearly be saving a small fortune by doing it myself.

It's worth pointing out that the IMF seems to have quite a few different names which could cause confusion (did me anyway). VAG call it the Intake Manifold Flap (IMF) but it's also referred to as an anti-shudder valve, regulating throttle, throttle valve and diesel valve. If anyone else wants to add to this list or correct me, please do!

 

[- Jrd -]

Just buy a 2nd hand Intake Manifold Flap, As you said yourself you can change it yourself. You can pick them up for £30+
Thats what i did, Also as result of failure of the IMF it will usually blow 10amp fuse on battery fusebox(cant remember which slot) so check fuses there

 

[chrisp]

Thanks for the tip Jrd - think I'll go with a new one as am pretty sure the design has been upgraded so I want to make sure I put something in that's the latest spec, which should hopefully be more robust, but I will check the fuses thx. :thumbsup:

I've just got a part number for an IMF from the main dealer (for a B7 2.0tdi 170PS): A 03G 129 711 AR

 

[chrisp]

!!!!!! CORRECTION !!!!!!: The part number in the above post is wrong (thanks to my Audi main dealer ).

According to the very helpful Murray's Direct, the above number is for a new Inlet Manifold and NOT for an Inlet Manifold FLAP, for which the correct part number is: A 03G 128 063 J

Main dealer cost £350+ vat - Murray's Direct (Genuine latest spec OEM Siemens-VDO): £182.50+vat

Ideally want to edit the above post but can't see the edit link anywhere today.

 

[chrisp]

New IMF fitted and no more judder when turning the engine off. I'm now pretty certain that the loop of gasket sticking out of the old one proved that it had blown, causing it to leak the oil that was below it in the engine bay and thus start sticking. Here's a shot showing old and new side by side and you can see the loop sticking out of the old one (on the left, obviously), and how it should look on the new - tucked in with just the small block bit showing..

Took her for a run and is smooth as silk - still can't get over how good it is to drive after cleaning the EGR and using the BG244 treatment. Obviously got used to it underperforming when clogged up with cr*p.

The only issue now is that the Emission Control Light is still on. I disconnected the battery while I did the IMF change in the hope it would clear it but it's still there.

Does anyone know if the VAGcom controllers you can get on eBay will reset the system and clear the light, or do I have to take her in to a dealer again?

 

[chrisk1700]

i see you have corrected me on the loop then mate, mine may have well gone to then? how much was it and from where?

chris

 

[Chris79]

Details of new part and supplier!

!!!!!! CORRECTION !!!!!!: The part number in the above post is wrong (thanks to my Audi main dealer ).

According to the very helpful Murray's Direct, the above number is for a new Inlet Manifold and NOT for an Inlet Manifold FLAP, for which the correct part number is: A 03G 128 063 J

Main dealer cost £350+ vat - Murray's Direct (Genuine latest spec OEM Siemens-VDO): £182.50+vat

Ideally want to edit the above post but can't see the edit link anywhere today.