VW sudden power loss issues

[kaanage]

Depends on how you drive it, but I'd say roughly every 1,500 to 2,000 kms.

Engine performance – you can definitely notice. Turbo boost is increased to counteract the leaner mixture used during the cleaning process which results in a hell of a lot of turbo lag. Engine noise increases dramatically and overall the car runs like crap.
Sometimes the ECU starts the cleaning process when the engine is cold which results in stalling, erratic idling and unburnt diesel coming out the exhaust because the engine's not up to operating temp and there's not enough fuel being fed into it, which can be interesting because coming up to intersections it either will stall or you have to rev the engine in neutral while braking. Once the engine is up to temperature it tends not to stall.

Actually, it is pretty much the opposite process - EXTRA fuels is injected during the regen, during the exhaust stroke where it ignites so that there is extra heat for the regeneration process. This creates additional backpressure in the exhaust stroke so the car runs like crap (and uses extra fuel pushing up consumption).

Lean diesel operation will generate less power but cooler engine/exhaust temps.

[alexaescht]

Actually, it is pretty much the opposite process - EXTRA fuels is injected during the regen, during the exhaust stroke where it ignites so that there is extra heat for the regeneration process. This creates additional backpressure in the exhaust stroke so the car runs like crap (and uses extra fuel pushing up consumption).

Lean diesel operation will generate less power but cooler engine/exhaust temps.

But isn't less fuel injected into the combustion chamber during combustion and then extra fuel is injected during the exhaust stroke? I read somewhere that a leaner mixture in a diesel increases NOx levels which increases temperatures helping to burn off all the soot.
I could be totally wrong but that's what I thought. Also (and I know these aren't always accurate) but the instant fuel consumption gauge normally sits at 0.4 litres per hour (at idle) and decreases to 0.2 and sometimes 0.1 litres per hour during a regeneration cycle.

[ill0gitech]

Has anyone experienced the power loss issues as reported in the media recently?

All electric power? No.

Lost power to the wheels? Yes, but not on a highway or at speed, but still dangerous. I've lost the ability to accelerate more than once whilst already moving slowly - specifically when changing lanes and turning corners.

[Hillbilly]

In days gone by, when cars did not have fuel or temperature gauges, these lights were known as "idiot lights". I am not sure the term "idiot" was aimed at the designers or the owners. In all probability it was the designers for being so stupid as to not providing a simple gauge.

Basically, when the light comes on, the engine has overheated. If there was a gauge, it would be in the red zone. The gauge would tell you how far into the red zone, and if it was continuing to climb.

If you are driving and the light comes on, pull over, stop where safe, and check under the hood.

By the way, the temperature gauge and simple warning light are of no use unless they can sense heat. If something like a coolant hose comes off, you may not get an indication of high temperature.

A friend of mine bought a MY11 Subaru Forester, and it does not have a temperature gauge. It has a coloured LED that changes from blue through orange and finally red. Not much use to him as he is red/green colour blind. To him, it is all the same brownish (his description) smudge.

Another example of not so good gauges are Toyotas which on some models dont register if the water drops out.

On my Landcruiser it would stay on normal until it got REALLY hot and then would move.
If however a hose blew and the water all went bye bye the gauge wouldnt move at all as it only worked when immersed in the coolant.

I put a sensor in the top hose to tell me if the water level dropped more than an inch

[wai]

But isn't less fuel injected into the combustion chamber during combustion and then extra fuel is injected during the exhaust stroke? I read somewhere that a leaner mixture in a diesel increases NOx levels which increases temperatures helping to burn off all the soot.

My understanding is that during regeneration, additional injector pulses are used when the exhaust valve opens to get a flame into the exhaust and take care of the soot, hence the additional fuel consumption.

[LunchboxVRS]

But isn't less fuel injected into the combustion chamber during combustion and then extra fuel is injected during the exhaust stroke? I read somewhere that a leaner mixture in a diesel increases NOx levels which increases temperatures helping to burn off all the soot.
I could be totally wrong but that's what I thought. Also (and I know these aren't always accurate) but the instant fuel consumption gauge normally sits at 0.4 litres per hour (at idle) and decreases to 0.2 and sometimes 0.1 litres per hour during a regeneration cycle.

NOx levels are reduced buy adding a innert gas (exhaust gas) into the intake which lowers the temp and reduces the available space for combust able materials. This effects efficiency but its a trade off to keep emissions low.
This is seperate to DPF regeneration. Most common rail diesels will inject several small injctions instead of 1 big one during the compression stroke and if needed 2 to start a burn on the exhaust stroke. if a burn is started the EGR which directs exhaust gas into the intake is closed. For regeneration to take place the exhaust needs to reach over 600 degrees. So cooling the charge air would not help so EGR is shut. NOx gases will go up during this time.

[alexaescht]

My understanding is that during regeneration, additional injector pulses are used when the exhaust valve opens to get a flame into the exhaust and take care of the soot, hence the additional fuel consumption.

NOx levels are reduced buy adding a innert gas (exhaust gas) into the intake which lowers the temp and reduces the available space for combust able materials. This effects efficiency but its a trade off to keep emissions low.
This is seperate to DPF regeneration. Most common rail diesels will inject several small injctions instead of 1 big one during the compression stroke and if needed 2 to start a burn if a burn is started the EGR which directs exhaust gas into the intake is close. For regeneration to take place the exhaust needs to reach over 600 degrees. So cooling the charge air would not help so EGR is shut. NOx gases will go up during this time.

Thanks for clarifying guys Makes much more sense now.

[gavs]

Has anyone experienced the power loss issues as reported in the media recently?

It seems overheating in some engines can activate the "limp home" mode. If my 6r Polo had a temperature guage, then I would have half a chance in preventing such scenario.

VEEEUU

Yes, when the mechatronics shat its pants in mine, I lost everything for 3-4 seconds that I could consciously notice while my brain was primarily trying to work out what the hell was happening. Can't comment on steering but I lost power, any accelerator effect, brakes, audio...

[yokom46]

Has anyone experienced the power loss issues as reported in the media recently?

It seems overheating in some engines can activate the "limp home" mode. If my 6r Polo had a temperature guage, then I would have half a chance in preventing such scenario.

VEEEUU

I've had something similar.

Driving at 110km/h on a highway and dropped to 4th to overtake a truck, it boosted nicely but as I got about half way along the truck I lost all boost, and the engine light was flashing.
I dropped it back up to 7th and pulled back in behind the truck where the engine light stopped and the EPC limp home light came on.

After a restart the car was fine, VW dealer in Phillip ACT said there was nothing in the logs indicating that it even happened. And sent me on my way.

Happened once since, the car is going back in next Wednesday for a worn clutch / dsg issue check.