Intermittant smoking 3.0

[Kev555]

Hi all my first post here since joining a couple of months ago. I have a 2013 A6 C7 3.0 TDI. Occasionally when the car stops in traffic it starts putting out excess smoke which stinks of diesel. I thought about the injector issue which I heard was in earlier models? but its too intermittent for an injector I think as I can drive around long and short journeys for a week and no issues and then it arises on a short trip and its gone the next morning? I'm thinking faulty  temp sensor or EGR? Any techs or forum users come across this before. help narrowing this down appreciated to speed up diagnosis.   

Edited January 6, 2022 by Kev555

[Steve Q]

I'd definitely recommend a diagnostic check as a failing maf, dpf or egr temp sensor or injector fault should come up. 

[Kev555]

Thanks Steve i did a diagnostic check a while back as ive a icarsoft cr pro, nothing came up obvious at the time in the fault codes, just a few historic minor ones. I guess I will have to try at get a look at live data when the problem arises. Never thought of the Maf, it has a temp probe too so could be that. thanks  

[Magnet]

Hello Kevin,

With the comparatively minor on cost expense, I would be treating this to a good dose of the Redex fuel additive, and half a tank full of premium grade (non supermarket) fuel, followed by a good sprightly run. 
Worth a try?

Kind regards,

Gareth. 

[Kev555]

Thanks Gareth might try that until the problem comes back.

[Kev555]

Finally got round to looking at the A6. I went through all the live data and could not find any tell tale signs from sensors etc. I dumped a can of purge cleaner in the tank for a few days to see how that goes. After test driving it yesterday I find that once the A6 is at normal temperature and after every lets say 5 mile run it smokes at standstill for about 1-2 mins then clears and is fine after that until you go for a run again. I'm thinking DPF issues at this point and next step i suppose is doing a regen. I tried a stationary regen with my icarsoft but just seem to get errors as if I'm not meeting the criteria correctly? Temperature on  the 02 sensors seems to be reading ok but some data from the DPF seems to be missing making me think its possibly been mapped out of the system if thats possible? or my icarsoft pro isn't fully compatible with the ECU. Any thoughts out there or should i just continue to suspect DPF?  

Edited January 25, 2022 by Kev555

[Kev555]

Managed to get a stationary DPF regen done today with another laptop. Ran for half an hour and medium diesel smoke the whole time during the regen similar to what it does when coming to a stop after a run. DPF is showing zero soot and info is a bit off from it. I'm wondering has it been doctored?

[Kev555]

Unplugged the MAF this morning as Steve suggested this could also be at fault and went for a 30 mile round trip. No smoking whatsoever at standstill during the journey. Should I order an MAF or would it not stop smoking anyways with the MAF unplugged even if it wasn't at fault? The temperature sensor seems to be behaving normally in diagnostics data and DPF doesn't seem to be the issue although cant be 100% sure. Could any Techs or forum members help me confirm the MAF, sorry if the info I posted so far isn't enough.  

Edited January 26, 2022 by Kev555

[Stevey Y]

3 hours ago, Kev555 said:

Unplugged the MAF this morning as Steve suggested this could also be at fault and went for a 30 mile round trip. No smoking whatsoever at standstill during the journey. Should I order an MAF or would it not stop smoking anyways with the MAF unplugged even if it wasn't at fault? The temperature sensor seems to be behaving normally in diagnostics data and DPF doesn't seem to be the issue although cant be 100% sure. Could any Techs or forum members help me confirm the MAF, sorry if the info I posted so far isn't enough.  

Hi to be honest I have used your diagnostic software before and found it to be lacking in its ability to interrogate the ECU and other modules, VCDS/OBD Eleven are much better, my guess is its not the MAF as when you disconnect it the smoking stops this is because the car goes in to a default strategy that shuts the EGR valve down, my guess is the EGR internal valve is sticking open sometimes and is still allowing to much gas through when it shouldn't , this would also cause problems with a forced regeneration and as for the car being doctored if the DPF was mapped out it simply wouldn't regenerate however good your software was.

Steve.

[Kev555]

Thanks Steve, a bit of a pin in my balloon but thanks for your input. Good to know before I buy a new MAF. I will go back tomorrow and try my laptop. Its got Wurth and Delphi which is pretty good software. I was picking up more codes with Wurth than anything else but there was no faults or codes from the EGR. I seemed to be  able to open close it via the software at tick over as the engine note changed but suppose I cant verify that its closing fully? Good to know the DPF is still operating as it should. Back to the drawing board again. Can you blank the EGR pipe in these handy without causing other issues or is it a software delete? I will try to get VCDS software.

Edited January 26, 2022 by Kev555

[Stevey Y]

On 1/26/2022 at 7:56 PM, Kev555 said:

Thanks Steve, a bit of a pin in my balloon but thanks for your input. Good to know before I buy a new MAF. I will go back tomorrow and try my laptop. Its got Wurth and Delphi which is pretty good software. I was picking up more codes with Wurth than anything else but there was no faults or codes from the EGR. I seemed to be  able to open close it via the software at tick over as the engine note changed but suppose I cant verify that its closing fully? Good to know the DPF is still operating as it should. Back to the drawing board again. Can you blank the EGR pipe in these handy without causing other issues or is it a software delete? I will try to get VCDS software.

Hi Kev its normally a software delete solution for the EGR as blocking it will throw an EML try unplugging the EGR and running it, from experience the EGR is monitored but only chucks out a code when the valve is well and truly stuck so the control unit cant open or close it, I had this on one of my Mondeos where I fitted a new turbo and within a couple of months it was throwing up codes for sticky vanes, I enquired with the company I purchased the unit from and they came back with its the EGR leaking, the EGR was only 15 months old  but I changed it anyway and shoved a can of cleaner through the turbo and it all stopped, I later took the old unit and poured white spirit in to the valve chamber and sure enough it leaked through and considering red hot gas is no where near as dense as white spirit it must have been pouring through the tiniest gap, but no codes, Delphi/Wurth are excellent softwares.

Steve.

[Kev555]

Thanks Steve If I cant cure it handy I might get it mapped out of the system especially when they have swirl flaps too from what I understand( have the same ballicks issue with swirl flaps on my Merc Vito). I will try unplugging the EGR when the smoke issue arises again. Plugged the MAF back in yesterday as wife was driving it today. she said no smoke today although she might not always be paying attention while on a shopping trip😁 I was overthinking this morning as usual and bear with me Steve to I get the basics hammered into my brain of what the car does while the MAF is unplugged. Is the EGR valve fully closed? i.e. reason for no smoke? and does the car just use a basic map with no or little emission equipment functioning? 

Edited January 27, 2022 by Kev555

[Stevey Y]

20 hours ago, Kev555 said:

Thanks Steve If I cant cure it handy I might get it mapped out of the system especially when they have swirl flaps too from what I understand( have the same ballicks issue with swirl flaps on my Merc Vito). I will try unplugging the EGR when the smoke issue arises again. Plugged the MAF back in yesterday as wife was driving it today. she said no smoke today although she might not always be paying attention while on a shopping trip😁 I was overthinking this morning as usual and bear with me Steve to I get the basics hammered into my brain of what the car does while the MAF is unplugged. Is the EGR valve fully closed? i.e. reason for no smoke? and does the car just use a basic map with no or little emission equipment functioning? 

Hi yes the EGR will be shut as the ECU  has no way of knowing the airflow/ambient temp of the air coming in so therefore goes into a default strategy which involves mixture enrichment so you don't burn valves, the map out is a good shout as its the EGR gas mixed with the oil from the crank case venting system that forms that sticky tar which in turn clogs the inlet manifold and enbalms the swirl flaps in thick black sticky crud, I think they do a swirl flap delete kit on eBay.

Steve.

[Kev555]

 

 

Thanks Steve I will have a look on eBay for the delete kit for the swirl valves. I'm thinking that the EGR now seems to be closed as theres no smoke this last couple of days with the MAF plugged back in. I'm wondering was the MAF holding it open a bit or did the unplugging of the MAF force it closed if it was gummed up? I cant confirm or know this is what happened for at least a couple of weeks to see if the problem arises again. Just a bit baffled that the issue is sorted ATM. I haven't even looked where the EGR is located and if its accessible for on car cleaning or freeing up. Thanks for you help so far Steve it was a big relief to find injectors are not at fault so far. 

Edited January 28, 2022 by Kev555

[Stevey Y]

2 minutes ago, Kev555 said:

 

 

Thanks Steve I will have a look on eBay for the delete kit for the swirl valves. I'm thinking that the EGR now seemed to be closed as theres no smoke this last couple of days with the MAF plugged back in. I'm wondering was the MAF holding it open a bit or did the unplugging of the MAF force it closed if it was gummed up? I cant confirm this is what happened for at least a couple of weeks to see if the problem arises again. Just a bit baffled that the issue is sorted ATM. I havent even looked where the EGR is located and if its accessible for on car cleaning or freeing up. Thanks for you help so far Steve it was a big relief to find injectors are not at fault so far. 

Hi, it might be its reset the EGR back to its closed position past the sticking point, considering most manufacturers consider 100k or ten years is the service life of most vehicles it will be over the 100k that the problems start, I would thoroughly recommend half a can of Lucas Turbo and EGR cleaner down the air intake pipe follow the instructions to the letter its amazing stuff and a cheap fix often as not.

Steve.

[Kev555]

Thanks very much Steve I will give it a go😁 130k on mine so its at deaths door. I stuck a can of liqui moly purge cleaner into about half a tank at the start of the week. Hardly likely that has shifted the EGR? 

Edited January 28, 2022 by Kev555

[Stevey Y]

1 minute ago, Kev555 said:

Thanks very much Steve I will give it a go😁 130k on mine so its at deaths door.

Hi it is not dead by a long way but they would love you to believe that and go buy another, if you look at it logically most of the stuff management wise is a 130k old but with limited expense and willpower there is no real reason why it won't do another 130k thats what pixxes them off, one of my Mondeos did 360k before it got terminated by an Astra van and even the guy who took it away said how well it drove and that was only a quarter of a mile to the recovery truck, its all about keeping the internals as clean as possible, shopping trips will kill your wallet faster than the car, LOL.

Steve.

[Kev555]

Had a Mondeo Zetec S a few years back, Wife loved the car and its still a fond favourite of mines too. Started to rust and rot along bottom insides of the rear doors so I got rid. I always like repairing and cursing at the cars I have. Bought an 06 Mustang which has been a long term dream in November. Always had that Ford bug so I'm happy to have a blue badge in the yard again. Absolutely love the 3 litre Audi for power and comfort as its our first auto box car and the wife which I thought might not get the hang of it wont stay out of the frigging thing. We had Kia and Santa Fe jeeps this last 10 years so didn't have to worry to now about speed humps🤬

Edited January 28, 2022 by Kev555

[Kev555]

After a few weeks running faultlessly the A6 started the same carry on again on Sat. I figured with Stevies help I unwittingly cured it the first time by manually opening and closing the EGR with the software on the laptop thus probably freeing it from the point that stopped it closing freely. Sprayed a full can of EGR cleaner into the air intake yesterday to try a handy clean. Drove it all day today and it smoked like a pig for the first hours driving then behaved perfectly all day. I will monitor it for now but if it gives me any more bother I think its going to get deleted by software next time. 

Edited February 15, 2022 by Kev555

[Kev555]

Finally got to the bottom of the smoking issue with the help of a diagnostic expert. Two owners back the car apparently got a remap and probably other tweaks done. The last owner got the car serviced with a main dealer who must have informed him that the car was remapped and I'm guessing advised the owner to put the original map back in the car which is what happened. I was able to see this from the service documentation I got with the car. The diagnostic guy I left it with was suspicious that the map Audi installed didn't actually install properly and was causing the smoking issue. He said it was a faulty DPF from what he could see so made me the offer of replacing it or bypassing it. I opted for the cheaper option and he left me to gut the DPF on my own time to save money. When I removed the DPF to my surprise it had already been drilled through at some point in its life which explained now why the car was smoking from the start according to the diagnostic guy. I just removed the rest of the DPF material to make sure there was no more issues arising when I went to the bother of removing the dam thing. So all good now so far