3.0 tdi weird behaviour.

bonifacy87

bonifacy87

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Something very strange happened today on the way home from work (19 miles trip mainly motorway). Firstly I was stuck in start stop traffic for about 4 miles. Then 12 miles nice and clear motorway. When I've reached my town and I stopped on traffic lights revs didn't drop to 600 as they usually do. They stayed at around 800 and the engine was shaking badly. It kept doing that at every light. No lights on dashboard. The revs gauge didn't jump much (maybe tiny movement hardly noticeable).
About a month ago I've banked my egr (only via software) and had swirl flaps removed. Although I don't think it has anything to do with it.
 
Sounds like it was doing a Dpf regen.

Shouldn't be shaking badly tho.
 
I would check it for any stored fault codes. You can have many different things failing or playing up and affecting the engine without getting an engine management light on.
 
I've got the car scanned and no errors at all.
Happened today again. Could blocked egr causing dpf to regen so often when doing two 20 miles trips to everyday. If this is dpf regeneration.
 
It's possible I suppose because you have done half a job with the emissions system by disabling the EGR that some kind of situation is occuring that results in this running issue when the DPF is being regenerated.
You can check the status of the DPF , How blocked it is, last time it was regenerated etc to see if was regenning when the issue occured.
I don't tend to believe in coincidence. If you made a change to the engine and now this has started happening they are likely to be related.
Was the car remapped because if so it's liable to regen more often.
 
No, car wasn't remapped.

Could you tell me how to check the dpf status and when it was last regenerated?

I know I only done half of a job. Don't really want to delete dpf for insurance reasons.

I'm going to Poland next Saturday so that should clean a dpf nicely. We'll see if this will happen again soon after I'll came back. If it will delete might be my only option.

What I also think is that because is cold outside at the moment and my car doesn't get fully warm until the last 8 miles of my trip and that isn't enough for a full cycle of dpf regen and that's why is trying to do it so often.

The only question is why is it shaking?
 
Sounds almost definitely like dpf re gen, fans only come on if you switch the car off while its doing or just done a regen
 
Shaking possibly due to you removing the flaps which i think would help regulate the airflow etc during elevated idle etC?
 
Could be right. Although sounds weird as it doesn't shake when I push a pedal and hold on the same revs.

I thought there shouldn't be any errors if egr was blanked properly in the system.
 
Is it a big job to reverse what you did with the EGR ? .The only thing I can think of is the throttle valve may be closing right up so the car is trying to run on EGR gas alone.
Where the EGR feeds back into the intake the throttle valve is located just by there. This valve closes down to create a flow restriction if the intake pressure is too high compared to the exhaust pressure so the car will then use more EGR gas. Exhaust gas is also hotter than air coming in so if you are trying to regen and need to keep the exhaust hot feed more EGR into the engine rather than cold air.
It's only a theory,
 
Tbh I'm not too sure what exactly was done to egr. Bobby did it all for me.

If I understand correctly my only options are Dpf delete or new egr and egr cooler (was showing insufficient flow before blanked) plus new swirl flaps.
 
A little update.
Car's doing it more often now. Still now errors on dash or when scanned with egr.
Had a good look at a revs needle today and the revs are about 100 revs higher than normal and the needle doest move at all.
Will try do the regen tonight on the motorway. Hope it helps.
 
Took a car for a spin tonight. Did 20 minutes on 4th at 70mph and when I've stopped to turn back car idling was increased. Did the same on the way back with few slow down and speed ups on full throttle and when I've stopped car was idling normal.
Hope that means that the car went through full cycle and there will be no problem for a while.
 
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