2010 polo 1.6 tdi engine anomaly

[davidlouis]

I am the 'happy' owner of the new 2010 polo 1.6 tdi...
happy that is except for one spot of bother...


This is my first diesel car and it has the new common rail diesel engine...
so far the car is 2 months old and has about 3500kms on the clock... I have observed all the vw dealer and owner's manual recommendations to drive conservatively for the first 1500-1700kms... and have mostly cruised around at a max speed of 120km/h so far with a few short bursts to around 140km/h... generally speaking the delivery of power is good, turbo works when it should and there are no indicator lights flashing on the dash. engine fluids are all as they should be too...

now for the weirdness...

normally when the car is stationary and idling when warm the rev counter sits at just under 1k and the fuel economy reading on the dash sits at 0.4l/h

Ar least three times in recent weeks, when cruising home after work at about 120-140km/h for a period of around 30-45mins on a moderate long motorway inclines, i have noticed something weird happening to the engine when i decelerate and come to a stop at a traffic light on my motorway off ramp.

If the engine has been pushed a bit on the uphills, my idle revs when stationary drop lower than the average (listed above) and the fuel economy reading reads 0.0l/h or 0.l/h and the engine appears to tumble/wobble harmonically... Its almost like it has still got excess momentum in it that is now being released... if i rev the engine in neutral it tends to 'switch' back or if i drive off, things return to normal but there appears to be a temporary lack of power/turno until it 'switches' back, usually at the next set of lights.

I have tried to describe this to the dealer (in laymans terms of course) and even taken the car in for a diagnostic but they tell me that there are no errors reported and that it has a clean bill of health... ??? so what is happening here... anyone have any ideas.

Could this have anything to do with the engine/turbo run in period and so do i need to take things easy for the next few kms... or could this be an indication of a progressive fault?

I would appreciate any help / advice anyone might be able to offer... in the meantime i will try and pinpoint the exact circumstances that create the anomaly...


Thanks in advance for any help...

Dave

[davidlouis]

Okay... so as many as 200 views an not much by way of a suggestion of what might be going on...

Anyway I have some more info (by way of frustrating observation) to add to the mystery...

Basically i came across this great site for VW/Audi TDI engines...

VW Audi DPF filter regeneration and Adblue system FAQ with DPF problems like clogging and why you can't do a DPF bypass or DPF delete with a kit

This alerted me to the fact that the DPF will undergo an active regen every 750-1000kms... and this seems to coincide with my refueling cycle +/- every 900kms...

The only issue is that this regen... in which fuel is injected into the DPF and ignited to burn off the soot, is supposed to be unnoticable to the driver but i seem to be noticing a fuel cut and limp mode when this happens which doens not seem normal to me...

If i keep on driving regardeless, things appear to return to normal after about 10 or so minutes... but is this causing any harm to the engine in the long run if left untreated...?

There are still no dashboard warning lights and the dealer said it had a clean bill of health when i last took it in...
The car now has only around 6500kms on the clock...

Anyone out there?

Thanks

Dave

[f.R.iend]

I have VW's 1.6 TDI for almost 6 months now. And after 15k kilometers I havent experienced anything like that. The engine runs smooth without any problems. Maybe it's the difference in diesel...

[shaunpolo]

Hi
I've had the same problem, low and lumpy tickover then a sudden burst of faster tickover - then the darn DPF light comes on. Then you have to undo all your carefully driving and fuel economy and give the thing a blast up the motorway! I am seriously fed up with this Polo and the dealer is completely uninterested. The fuel consumption is poor at low 40's to the gallon, nowhere near the 67 claimed, not even above 50! Car has done 3500 miles and the delaer keeps saying "wait unitl it's done 6000 miles". Absolute rubbish, my mum bought a brand new BMW 120d and the thing returns 55mpg from the day it rolled out of the show room. Am on the brink of selling. Been back to dealer with DPF light on - gave me an information sheet about driving it hard up the motorway to get rid of the light, and also been back about the lumpy tickover. Not interested! Wish I kept my 2006 1.4 3-cylinder 80bhp model which never missed a beat.

[davidlouis]

Thanks for your replies

I would seem to agree with the idea that the diesel here in Africa may be a little more 'dirtier' and might be giving the DPF a hard time...

I know 500ppm diesel will clogg the DPF up quickly and have been careful to only use 50ppm clean diesel from BP and shell... so as far as i am concerned i'm following best practice.

Still I am getting around 55mpg (5.1l/100kms) for mixed driving... so the engine must be doing something right... I know it might be a bit worse that the quoted consumptions but traffic / terrain etc etc can do a lot to upset the factory figures which probably were achieved in a lab somewhere under ideal conditions anyway...

Despite this 'engine hiccup' I'm still loving the car although i know there are a lot of people out there who don't... see this site for some more unhappy campers... VW Polo 1.6 TDI | First Drives | Car Reviews | Auto Express

I'm going to keep the faith and see what happens... will wait until my first service in about 3 months time to see if the issue clears or if a diagnostic throws up anything...

Will post any more of my findings as and when...

If anyone else has any theories to share in the meantime, please let me know....

Thanks

Dave

[kripstoe]

Originally Posted by davidlouis

I would seem to agree with the idea that the diesel here in Africa may be a little more 'dirtier' and might be giving the DPF a hard time...

It's supposed to regen every 750km or so depending on driving style etc. Mine does it too.

Originally Posted by davidlouis

I know 500ppm diesel will clogg the DPF up quickly and have been careful to only use 50ppm clean diesel from BP and shell... so as far as i am concerned i'm following best practice.

Only use 50ppm.

Originally Posted by davidlouis

Still I am getting around 55mpg (5.1l/100kms) for mixed driving...

My combined is also 5.1, which seems normal for my driving style. I can get as low as 4.2 if I drive more carefully.

Originally Posted by davidlouis

Despite this 'engine hiccup' I'm still loving the car although i know there are a lot of people out there who don't... see this site for some more unhappy campers... VW Polo 1.6 TDI | First Drives | Car Reviews | Auto Express

The TDI we have in SA is different spec to that of Europe. We have less filters than they do in their cars, and we have the 77kw version which they don't in the UK, so it's not really fair to quote the above link.

Originally Posted by davidlouis

I'm going to keep the faith and see what happens... will wait until my first service in about 3 months time to see if the issue clears or if a diagnostic throws up anything...

Nothing wrong from what I can gather with your car. Mine does the same. The regen takes about 10-20mins, and that's it.

There has been a DPF software update for the car (ask your dealership about it). I've done 22000km already and have not have any issues.

[davidlouis]

So she went in for the first service...

Asked for a ECU faults log check up too... clean bill of health... All current ecu and DPF software versions apparetenly installed at pre delivery stage as otherwise dealer says it would have popped up in the vehicle history...

DPF issues have settled down... or otherwise i have become used to the 'hiccup'... giving the car a good run every so often seems to help clear the 'plumbing'...

Fuel economy is good... and consistent... managed a 4.3l/100km on a recent long journey.

Looking forward to the next 15,000kms stretch.

[Supernut77]

Hi

I have had the same issues on my (early) 2010 TDI...

• Idling issue started a few months after I bought the car
• Fuel consumption at best average 5.8-6 l/100km

Initially thought the idling was due to using the cruise control, but after various "scenario tests" done by myself noticed that it had no influence.

The Polo has been to the dealers around 6 times, including once for the 15,000km service (where they also looked at the issue - see software). Dealers indicated that they:

• Updated the software to the latest version
• Checked all the filters
• Did all the pressure tests
• Technician even removed plugs and manually checked them
• Checked for leaks

The car would be fine for a week or two after it has been in, then the erratic idling would be back. Last time the car was in was 02/02/2011 (my son was two days old) when, the day before, I also had the Engine Management System as well as Catalytic Converter warning lights came on. This when the idling issue presented itself again on 30/01/2011.

Needless to say I am at my wits end. This because the erratic idling started this morning yet again, and then again this afternoon. Fuel consumption is slightly better, lower 5's, but still not on par. Especially since I drive very carefully (50-60 km/h urban, 110-120 km/h national roads) and keep the rev's mostly between 1,000-2,000 (obviously may go to 3,000 when I need to accelerate).

Made sound clips on my cell, which have been given to the dealer, they said they will send to the factory. I think they have done all they could with their immediate resources, we will have to see whether VWSA or the like will help.

This was my dream car - I always wanted a diesel, compact, light on fuel, better for the environment, power when I needed it. And of course, WCOTY. Doesn't help that we get ripped with car prices here in RSA and pay a premium for diesel cars - mine cost R210,000 (+/- GBP 18,100 or USD 29,400).



You can listen to the attached sound clip - just unzip. Happened this morning. Starts with erratic idling around 13 seconds.

P.S. the car only gets 50ppm diesel

[kripstoe]

Originally Posted by Supernut77

[*]Technician even removed plugs and manually checked them

Huh? Since when does a TDI have plugs? What dealership did this?

It's not a catalytic converter light, is a DPF light.

The sound clip sounds like a regen cycle in progress. How often does the "idling issue" happen? What happens if you go for a drive for 10-20 mins while the "idling issue" is in progress (keeping the revs at 2000rpm) and stopping?

If you need to rev to 3000 when accelerating you're not going to get very good mileage.

If I drive carefully I easily get below 5, and driving hard gets between 7 and 8.

[Supernut77]

Originally Posted by kripstoe

Huh? Since when does a TDI have plugs? What dealership did this?

It's not a catalytic converter light, is a DPF light.

The sound clip sounds like a regen cycle in progress. How often does the "idling issue" happen? What happens if you go for a drive for 10-20 mins while the "idling issue" is in progress (keeping the revs at 2000rpm) and stopping?

If you need to rev to 3000 when accelerating you're not going to get very good mileage.

If I drive carefully I easily get below 5, and driving hard gets between 7 and 8.

@kripstoe

1. Just quoting the tecchie (assumed he was talking about oil plugs)
2. Warning lights were "Fault in catalytic convertor" and "Fault in engine management system" per owner manual
3. Idling issue happens on-and-off. Driving 10-20 mins with the issue makes is worse, i.e. idling becomes more erratic (note the issue refers to really erratic idling)
4. Acceleration to 3,000 rpm very rare, but thought that I would mention it. I normally change gears around 2,000 rpm
5. I drive carefully and my latest computer reading shows 5.8 average (fyi only 20% of my daily route is in traffic, 80% against) and I leave the aircon off as much as possible

And in the vein of fuel consumption, read this on the local website where the Polo won the the Total Economy Run.