Stop start not working, over idling and smell of diesel fumes

[kyle92]

Evening Chaps,

I have an issue on my polo that I have had for some time now (over a year now), more often than not, every day my polo will over idle, going from 800rpm up to about 1100-1200, during this I can smell diesel fumes and the stop start won't work, in addition I genuinely can't remember the last time my stop start worked.
My mpg has been considerably lacking compared to when I bought the car as well, now my average is around 60mpg indicated (from tank fill up to refill) if I am lucky, when I bought it I was getting an easy 65-70 and sometimes 80mpg indicated.

I had my cat changed not long ago as well as the flexi so I doubt they would be the issue, I took it to my mechanic and he was slightly confused to it, fortunately as he started it up to check for codes with his reader, the car did just what I described, no codes were present and nothing has appeared still, he has no idea what is causing this issue.

I commute about 10 miles to and 10 miles back from work daily, mostly motorway, at least once a month I take it a long drive (at least 45 minutes) and give it some welly on some B roads to make sure the regen kicks in and it is sucking some fresh air back in to burn off the sh*t.

I have heard of folk rolling back the maps a previous version to counteract the dieselgate software that was put into this at the factory with considerably better performance and mpg results, anybody got any thoughts on this as well?

Cheers,
Kyle

[amer6R]

Blocked egr

[kyle92]

Would I have to remove the EGR to confirm this?

[iichel]

Isn't it just in a dpf regen?

[amer6R]

Would I have to remove the EGR to confirm this?

No, remove the metal pipe that goes into throttle valve inspect if its clogged with carbon. ( Torx t30)
In my previous car i had smell of diesel in cabin egr vas clogged, after cleaning issue was gone. Thats why im suspecting.
Btw. When my car does a rengen it doest smell on flue.

[SimonPoole]

Sounds like the DPF is doing a regen. Try giving the car a run for about 15-20 minutes at over 2000rpm with the engine hot.

Also, I've had the software on my son's 1.2TDI rolled back and it drives far better now than before and doesn't regen as often either.

[kyle92]

Sounds like the DPF is doing a regen. Try giving the car a run for about 15-20 minutes at over 2000rpm with the engine hot.

Also, I've had the software on my son's 1.2TDI rolled back and it drives far better now than before and doesn't regen as often either.

I have ran my car with an OBD plugged in and checking the regen status on my phone with an app, my car does this 'poor running and over idle' both during regen and out with of it.

As I said in my original post I make sure to give it a good run at least a few times a month but it gets a fairly decent run each morning as well so it's not like I am doddering through town at 15mph all morning, I get on the motorway for at least 15 minutes on each way to and fro work.