2.0 tdi - strange issues 60 seconds after start up!!!

[Lion Heart]

Hi guys!

I'm having an issues with my 2.0 TDI. I've posted before, and working for a solution, so thanks for sticking by me if you read mypast post. But a very interesting development...

Basically, I'm getting a rough idle and lots of smoke when COLD (100% fine when warmed up).

Now, the interesting bit...

Having run some tests on this I'm finding that the car is 100% FINE for the first approximately 60 seconds or thereabouts. THEN the rough idle and smoking begins.

When you first fire it up super-smooth, no issues. Wait around 60 seconds, engine shuddering on the idle, and lots of smoke.

No overheating issues, no 'cheese' on the oil cap, pretty sure it's not a head gasket issue.

In the past on a petrol I have leaking valve rings, but that would smoke immediately upon start up. This does not.

If it were injectors it would again do it straight away, not suddenly after 60 seconds.

I thought maybe EGR valve as I believe that is not open when engine first started, but kicks in soon after? I removed the EGR valve and intake manifold, and cleaned both (not too dirty to be fair), tested EGR valve with VAG COM. All good.

So, what kicks in at around 60 seconds AFTER starting the engine that is not active when you first start it?

Here are the video's of my symptoms AFTER the 60 seconds approx:





Thanks guys!

P.S. I actually have an A6 2.0 TDI rather than A4. I have also posted this on the A6 forum, but that forum seems very quiet so hoping for more luck here. As the A4 uses the same engine should be the same across both platforms. Please do not move this post. Thank you.

 

[Sp3no82]

Are you losing any coolant?

 

[Lion Heart]

No, coolant level is good.

 

[mm707]

Mine's exactly the same. Fairly common problem. I've not had mine fixed yet but avon tuning near bristol fix this for about £270. They adjust the cam timing and map out the egr. I'm wondering if just mapping out the egr will fix it. From what i can gather the egr kicks in soon after start and stops when warm. It's a right pain in the cold weather when you're in traffic and there's a cloud pouring out of the exhaust.

 

[Lion Heart]

Hey mm707

Thanks for the input, much appreciated.

I've seen the Avon tune come up in discussion on the forums with regards to the 2.0tdi smoking issue a couple of times, so must be something to it.

However, let's say in theory the EGR delete and cam timing adjustment solves this issue, the question remains as to WHY it's throwing out that much smoke and juddery idle.

Yes, from what I understand the EGR valve does not open immediately upon engine start up as it needs to warm, but kicks in soon after, so that could align with the no problems until around 60 seconds part.

But why so much smoke? EGR valves shouldn't smoke that like if all they are doing is their standard factory operation that they will have done since day 1?

I guess a test would be a blanking plate on the egr valve. It will throw the engine management light, but that can be reset with vag com once the test is complete and plate removed.

I guess if the blanking plate eliminates the smoking and juddery idle after 60 seconds then there must be something to this theory?

 

[Calasp]

My A4 does this has it recently had a cam belt change??? If it has it’s the timing
It will need adjusting with vagcom

 

[Lion Heart]

Actually yes, not that long ago. I've only owned it a couple of weeks.

I've been researching exactly that actually as I found some posts with people with the same symtoms, and most people it occuredafter a cambelt change.

It seems you can use vag com to take the timing reading on the PD engines, but the adjustment is manual, not via software. But the belt stays on to adjust so not a big job. Take the reading, if off adjust, take the reading again.

It could well be the cause of the problem, especially as a lot of people have the exact same issue in the post I found.

 

[Allyn78]

I had this problem after replacing the timing belt, solved the problem by blanking off the egr valve, bought the blank off plate from eBay placed it between the egr valve and pipe from turbo. Doesn't rough idle any more or white smoke on warm up. No management light up on dash.

 

[Lion Heart]

Thanks guys!

Well, inlet manifold also removed and cleaned, again pretty tidy already.

Ran a quick check for vacuum leaks and could not find any.

I ran some injectors cleaner through the fuel and took readings from the injectors when engine warm a few days later, and getting decent readings back on those.

I also did a full service on her as well, including coolant change.

HOWEVER, the smoke has now virtually stopped!!! I'm wondering she had too much oil?

There is still the juddering when cold, but not half of what it was. And no smoke worthy of a mention!!!

So that's good news!

When I did the service I also change the fuel filter. I poured out the old fuel, and it was bluey. But remembered that the additive to clean the injectors was green, so mixing that with yellow diesel would equal blue. No oil in it as such (i.e. nothing trying to float or sink), but the whole lot dark blue in colour, but think that's likely the injector cleaner.

NEXT: I have spotted that the cambelt (which was a DIY change by the previous owner) tensioner is not set correctly. It has an arrow which should sit within a groove (slot) on the rear plate, or up to 5mm to the RIGHT of it. Mines 5-10mm to the left of it!!!

So looks like I'm going to have to remove and refit a new cambelt as well and make sure that the timing is 100% spot-on.

Found a LOT of reports on the forums (mostly from 2.0 TDI owners) experiencing rough idling and smoke after a cambelt change. So getting that cambelt 100% spot-on won't be a bad thing!!

 

[Lion Heart]

Hey Allyn78

If your issue occurred after the cambelt change it's likely that the cambelt needs slight adjustment. Most likely on the inlet cam I believe.

Was the plate you used solid, i.e. no hole? Usually that should throw the engine light on?

 

[mm707]

I tried a blanking plate with a hole in, it did idle better but it seemed to have hesitation sometimes pulling away from a stop. I've taken it out.
My timing belt was fitted by main dealer, the juddering though seemed to originate from when I had the injectors changed on the recall about 4 months later.

 

[Lion Heart]

That's very interesting! Maybe the cambelt timing was tweaked on the exhaust cam to set the fuel consumption correctly, and when the injectors were changed these would be more efficient as brand new and so throwing it out a bit.

In which case an adjustment to the exhaust cam could solve in theory.

It may be worth getting the consumption figure on VCDS and ensure it is running between 0.4 and 0.6lph.

 

[Calasp]

That's very interesting! Maybe the cambelt timing was tweaked on the exhaust cam to set the fuel consumption correctly, and when the injectors were changed these would be more efficient as brand new and so throwing it out a bit.

In which case an adjustment to the exhaust cam could solve in theory.

It may be worth getting the consumption figure on VCDS and ensure it is running between 0.4 and 0.6lph.

How would you do this?? Checking the comsumption figure?? As my car doesn’t seem to be get the mpg it should but I put that down to the timing
I’ve got rough idle and smoking on idle I’ve recently changed the timing from 2.7 to 0.75 it is running better but still rougher then I’d like and the smoke I had got better but still not right!!! Any ideas?
I’m thinking it’s had a rubbish map on it

 

[Lion Heart]

I'm no expert, just learning as I go

You can check the consumption figure using VCDS. Do you have that?

 

[Calasp]

No but I have a friend who has it

 

[Lion Heart]

It's in the measurement block section, group 015, third box along labelled "Fuel Consump."

Hope that helps