2.0 TDi BKD Electrical Fault on Glow Plug Cylinder 2 - Misfire smoke etc.

[Joe90k]

Hello all,

Long time no post!

My car has recently ticked over 100k miles and I think unlike most I have had relatively few (touches wood...) problems with it. It started ticking over badly a little while ago, basically it kind of stutters on tick over, sounding like it is misfiring until you rev the engine. It also occasionally miss fires at about 3.5k rpm when driving it. I have done a lot of research into this and I think it's the loom which goes into the engine that is a common fault. I also get some white smoke which I think is unburnt diesel, but might be coolant... not too sure on that. I got this last night from VCDS:

Saturday,04,August,2012,23:10:05:26365
VCDS Version: Release 805.2


Address 01: Engine
Control Module Part Number: 03G 906 016 DT
Component and/or Version: R4 2,0L EDC G200AG 5878
Software Coding: 0000078
Work Shop Code: WSC 66565
2 Faults Found


17056 - Cylinder 2 Glow Plug Circuit (Q11): Electrical Fault
P0672 - 000 - -
Freeze Frame
RPM: 0 /min
Torque: 136.0 Nm
Speed: 0.0 km/h
Load: 0.0 %
Voltage: 11.63 V
Bin. Bits: 00101100
Temperature: 9.0∞C
Bin. Bits: 00110000


16618 - Boost Pressure Regulation: Limit Exceeded (Overboost Condition)
P0234 - 000 - -
Freeze Frame
RPM: 3780 /min
Torque: 340.0 Nm
Speed: 80.0 km/h
Load: 92.5 %
Voltage: 14.21 V
Bin. Bits: 00101000
Absolute Pres.: 2376.6 mbar
Absolute Pres.: 2590.8 mbar




Readiness: 0 0 0 0 0

I have changed all the boost pipe seals as I know I had a problem with them seeping boost which helped, but I am still convinced there is an air leak somewhere... How can I check this on VCDS? It has gone into overboost around three times since I have owned it, once because it was hot and I had a full car just after having it mapped and once because I fully blew a boost pipe off (I have the forge silicone items)

Aside from that I am also loosing some coolant, but nothing to cry home about, (pretty sure the head is not porous, it's the B variant and has been fine up until now) around half a litre in three months, I think this is due to the end caps on my radiator and will check this in a couple of weeks when I get it up on a ramp. I noticed this when I first bought the car but didn't worry about it as it wasn't loosing any coolant, there is not enough coolant lost for the amount of white smoke I see either which is why I think it's unburnt diesel.

Any help would be great!

Cheers,
Joe

 

[mike foster]

The glow plug fault has nothing to do with the lumpy running as the glow plugs only work to start the engine.

The stuttering could be something to do with the injector wiring loom - see this thread :- http://www.audi-sport.net/vb/a3-s3-...64348-three-faults-coming-up.html#post1644757 for details and loom part numbers.

As far as coolant/white smoke is concerned what does the underside of the oil filler cap look like ? If it's covered in a creamy emulsion type liquid then that indicates water in the oil and I think you know what that could mean !!

An air leak will not cause overboost as that is usually an underboost situation. Overboost is usually caused by sticking turbo vanes and eventually will probably need a new turbo unless you can clean them satisfactorily.

 

[Geraldy212]

With the fault showing up on a glowplug and the missfiring, I would certainly suspect the injector/glowplug loom as being the culprit. The glowplug fault would not affect tickover. Not sure about the white smoke though. If the injector works, then the cylinder will ignite, no fuel injected, no smoke produced....???? You do need to check that radiator asap. 'B' heads have been known to give trouble, so it's well worth checking out. Good luck.

 

[Joe90k]

Right, after some advice I changed the in tank lift pump, it needed replacing, it was causing hard starting and I thought it may explain the stuttering. I had 1K0 919 050 B and I replaced it with the D variant which did make starting much better but made no difference to how it runs. Now its still jerky and when the car is under load, particularly up a hill it really struggles. I have to down shift to get it around.

I'm sure there's an air leak, either vacuum or boost, is there any way I can measure this with VCDS? Or do I just need to look in the engine bay?



Thats a video of tick over. Please help I have no idea where to look next and need the car sorted!

 

[moggie93]

I had a very similar problem with my tdi golf.
The idle was slightly lumpy, the car would drive ok on light to moderate throttle, but when using full throttle the car began to run very lumpy like it was running on 3 cylinders. When the car was scanned for fault codes it showed similar faults to yours.
I changed the injector wiring loom and it made a slight improvement.
eventually I put the car into a diesel specialist and it was diagnosed as a faulty tandem pump. The pump was not supplying enough fuel pressure.
There is a small port on the pump where a pressure gauge can be installed to check the pressure.
hth M

 

[Joe90k]

I had a very similar problem with my tdi golf.
The idle was slightly lumpy, the car would drive ok on light to moderate throttle, but when using full throttle the car began to run very lumpy like it was running on 3 cylinders. When the car was scanned for fault codes it showed similar faults to yours.
I changed the injector wiring loom and it made a slight improvement.
eventually I put the car into a diesel specialist and it was diagnosed as a faulty tandem pump. The pump was not supplying enough fuel pressure.
There is a small port on the pump where a pressure gauge can be installed to check the pressure.
hth M

Can you elaborate on the test? I have spoken to a few garages and searched online but have been unable to find anything relating to testing the tandem pump.

After thinking changing the lift pump helped the hard starting I was wrong, the issue is still there. Someone suggested to me that the injector seals could be gone as this is common and would explain the hard start after leaving the car overnight i.e. only when it starts from cold. I have also been suggested that the EGR cooler could be leaking coolant into the engine, I am loosing coolant, but very slowly. I changed the fuel filter a couple of weeks ago and it looked like this:

As you suggested I think the tandem pump needs replacement, I will be doing this first I think as I seem to have all the symptoms; low fuel pressure causing bad idle/terrible juddering under load and oil in the fuel filter. The filter in the picture above was around a year and 3 months old when I changed it.

Joe

 

[moggie93]

Hi joe, on the side of the tandem pump on the 1.9 tdi there is a silver plug with an Allen key socket on it. This is removed and a fuel pressure gauge can be fitted to check fuel pressure from the pump.

you can see the plug on the photo above.

Ive just had a misfire on my a4. Light throttle was ok but anything more induced a misfire. I replaced my fuel filter with 2 small inline filters as I didn't have a replacement. This cured it again.
Hth M

 

[Joe90k]

Just wanted to update this to say the problem has now been sorted, it got progressively worse until it was a constant misfire. Injector 4 had failed, causing a violent juddering. After replacing the injector loom and injector unit, it is now fine. Tandem pump was not to blame although it may still be faulty. I am also chasing a boost leak which I can't seem to find, I may need a new turbo too but will be upgrading instead of replacing it.

Expensive month for me! Can't complain too much I have had 56k miles of trouble and repair free motoring.

 

[Harjsgill]

Hi all, I have a similar problem, Audi a3 05 plate hesitates under load every few minutes it even cuts out now and again. It has had the following done. New Garrett Turbo due to a well known specialist saying it was over boosting. Still no joy so new fuel filter, new injector harness and a new intank fuel pump. As you can imagine this has been very expensive and still no joy. There are no fault codes. Please help