What is it with this "regeneration" thing ?

[dcdick]

As the title says .........

550 miles mixed driving with an eye on economy & struggling to get over 50mpg :confused:

Last week the car went into "regen" mode after a run down the motorway when it was parked up

Today it has done this 3 times after journeys of about 7-8 miles :(

Anybody any ideas (I will be contacting the dealer in the morning) ?.

Am certainly not going to put up with this fuel wasting nonsense as driving conditions are ideal during this warm spell we are experiencing lately.

I was sold the 1.6 diesel over the 1.4 TSI purely on the basis of fuel economy as the price was the same to lease with no premium for the diesel & as the performance of the 1.6 is fine for my needs it seemed like a win-win deal :(

What are people getting from their 1.6 TDI "blue motion technology" cars?.

My long term reading (by the car) is standing at 48.5 mpg which is 25 mpg shy of the published figures or around 32% less than it should be.

I know about the published economy figures & I should get within 10% of these seeing as I drive carefully. Will the engine "loosen up" enough to affect the fuel consumption figures enough to bring it up to where it should be ................ I don't think so !

The car is great to drive & the tech stuff fitted does make things easy but this fuel consumption/regen business is starting to annoy me & I get the feeling the dealer is going to stonewall me tomorrow (may be wrong though !)

Previous car was a 61 plate QQ diesel that had none of this regen stuff going on.

[mcmaddy]

what diesel have you been using?

[dcdick]

what diesel have you been using?

Shell & Esso, 2 lots of Shell & 1 of Esso so far. Standard diesel.
Shell today, had already had 1 "regen" before putting fuel in today.
Of the 3 garages I use for fuel 2 are Shell & 1 is Esso, Shell is my preferred fuel though but don't have a compelling reason to use Shell over Esso.

No BP garage near me come to think of it.

[Doctle Odd]

You can get the DPF removed, I hate them and EGR's. Your mpg is low even for dirty diesel on that engine. I'd start with a VCDS scan. You can get a forced regen as well

[algarve]

As the title says .........

550 miles mixed driving with an eye on economy & struggling to get over 50mpg :confused:

Last week the car went into "regen" mode after a run down the motorway when it was parked up

Today it has done this 3 times after journeys of about 7-8 miles :(

Anybody any ideas (I will be contacting the dealer in the morning) ?.

Am certainly not going to put up with this fuel wasting nonsense as driving conditions are ideal during this warm spell we are experiencing lately.

I was sold the 1.6 diesel over the 1.4 TSI purely on the basis of fuel economy as the price was the same to lease with no premium for the diesel & as the performance of the 1.6 is fine for my needs it seemed like a win-win deal :(

What are people getting from their 1.6 TDI "blue motion technology" cars?.

My long term reading (by the car) is standing at 48.5 mpg which is 25 mpg shy of the published figures or around 32% less than it should be.

I know about the published economy figures & I should get within 10% of these seeing as I drive carefully. Will the engine "loosen up" enough to affect the fuel consumption figures enough to bring it up to where it should be ................ I don't think so !

The car is great to drive & the tech stuff fitted does make things easy but this fuel consumption/regen business is starting to annoy me & I get the feeling the dealer is going to stonewall me tomorrow (may be wrong though !)

Previous car was a 61 plate QQ diesel that had none of this regen stuff going on.

I have to say I wonder whether leasing a diesel was the right move unless you do high mileage journies.

Journies of about 7-8 miles the DPF is never going to get hot enough to passively work.

I still think its early days with only 500 miles in total on the clock as well.
I assume rightly or wrongly you don't do that a high mileage as you posted you were' not far from what you hoped for at 54mpg ' ( at 350 miles ) a couple of weeks ago.

I personally don't think you will get much joy from your dealer at this early stage.

[dcdick]

I have to say I wonder whether leasing a diesel was the right move unless you do high mileage journies.

Journies of about 7-8 miles the DPF is never going to get hot enough to passively work.

I still think its early days with only 500 miles in total on the clock as well.
I assume rightly or wrongly you don't do that a high mileage as you posted you were' not far from what you hoped for at 54mpg ' ( at 350 miles ) a couple of weeks ago.

I personally don't think you will get much joy from your dealer at this early stage.

I personally disagree with the "high mileages only" for diesels..............all taxis/delivery vans etc... are diesels & most of them are "stop start" journeys that are quite short mileage wise.
The mpg figure is worsening, it could well be due to the filters are using extra fuel on the "clean" cycle & if what you say about the DPF needing such a long time to reach operating temperature is correct then I find this unacceptable.
I did ask about this when choosing the car & was assured that unless I did a lot of very short journeys of "less than a mile or so" there would be no problem with DPF etc... & "anyway the car will just run through a cycle automatically if needed"

"Early days with only 500 miles" possibly, but the economy is never going to improve by 30% with some more miles on is it ?

Well, we'll see what the dealer has to say about this later today......... I'll post up what happens :D

Something is not correct here & needs addressing

[vc-10]

Yes, the DPF will use fuel when regenerating. I wonder if it's the typical VW issue of bad injectors as was mentioned in the 2.0 TDI thread?

[dickt]

I agree about excessive regens in the early miles. For what it is worth, my 2.0/150/GT did excessive regens for about the first 2000 miles. It maxed out at 3 in one day with only short journeys. As I reported elsewhere, this negatively impacted mpg. I talked to VW customer service, who said I should book it in at a main dealer for a complete computerised check. The dealer did not want to do the checks and was unpleasant. However, they must have done something, as since then the regen frequency has reduced, and the mpg has gone from 41/42 to 45/46. At last this new 25k car is doing the mpg that my Mk 5 2.0/170/dsg did with ease, after VW replaced both the regen kit and all the injectors. If they did not do anything - and maybe they did not even do the checks, maybe the engine settles down after 2,000 miles or thereabouts.

[maisbitt]

I personally disagree with the "high mileages only" for diesels..............all taxis/delivery vans etc... are diesels & most of them are "stop start" journeys that are quite short mileage wise.


High mileage for diesels, maybe not, but significantly lower than average mileage for diesels is a valid point. I'm not talking about people disregarding the choice of diesel by saying things like "you'll never get your money back unless you're doing 20k miles a year" etc.

It is all about the DPF. You need a decent journey length a few times a week for the DPF to unclog. You've had your car for almost a month now and one of your first journeys was a 90 mile round trip, so you've averaged 18 miles a day excluding that one trip (for 550 miles total on the clock). If you're doing 5 miles here and 6 miles there on every trip then the DPF won't be getting a passive workout and will be trying it's best to do a forced regen a lot of the time you're out in it.

The argument doesn't apply to taxis as even though they do lots of short journeys, those journeys are accumulative - the taxi's engine doesn't have time to cool down between trips and so passive regen is going on all the time.

Forced regens make the car thirsty for those trips it's happening on. If the car is trying to go through on on nearly every trip then your mpg is going to suffer quite badly.

I don't think your situation with mpg will improve without intervention. If my assumption about your journeys is incorrect e.g. you do that mileage by fewer and longer trips rather than using the car daily and you regularly go at least 10 miles on a single trip doing motorway speeds (to get the engine temp up for a good few miles before your journey finishes) then the car is the problem, not your driving habits. In that case VW might be able to perform a warranty remap. Initial teething troubles with DPFs on TDIs are sorted for the 2.0 unit, not sure whether the same stands for the 1.6 unit.

The suggestion to remove the DPF is a no go. VW can supply non-DPF cars to certain markets whose legislation allows it, but trying to remove a DPF system already in is a tall order that VW officially say cannot be done. It is so tightly integrated into the fuelling/engine management and exhaust systems that removal will be quite costly to have done independantly and will probably render your VW warranty useless for any engine issues you may have in the future.

[maisbitt]

I agree about excessive regens in the early miles. For what it is worth, my 2.0/150/GT did excessive regens for about the first 2000 miles. It maxed out at 3 in one day with only short journeys. As I reported elsewhere, this negatively impacted mpg. I talked to VW customer service, who said I should book it in at a main dealer for a complete computerised check. The dealer did not want to do the checks and was unpleasant. However, they must have done something, as since then the regen frequency has reduced, and the mpg has gone from 41/42 to 45/46. At last this new 25k car is doing the mpg that my Mk 5 2.0/170/dsg did with ease, after VW replaced both the regen kit and all the injectors. If they did not do anything - and maybe they did not even do the checks, maybe the engine settles down after 2,000 miles or thereabouts.

Dealership technical remap most likely - went through this with my 2007 170TDI MK5 Golf. I really thought they'd nailed this as my 2 TDI Sciroccos (both with DPF) have been no bother at all.

[Doctle Odd]

A good 20 minute drive at 70 mph will make it regen just keep the revs up when youre doing it

[maisbitt]

A good 20 minute drive at 70 mph will make it regen just keep the revs up when youre doing it

As above. When a TDI is doing a regen you can see the prompts for gearchange suggestions in the MFD change. My car usually suggests an upchange from 4th to 5th at 30mph if you're just maintaining speed, but when it regens, it won't suggest the 4th to 5th upchange until about 38mph. It likes to be kept 1800-2500 rpm when doing a regen.

[dcdick]

Some interesting observations here about the regen situation & peoples take on things.

Previous car Nissan QQ diesel with the same DPF setup only did a regen once that I was aware of over 15,000 miles of mixed driving, it appears earlier models needed a software update to stop this happening. I find it very disappointing that a "quality" brand such as VW cannot get a diesel engine to run properly after all this time

My opinion is that this regen nonsense should have been sorted long ago by VW :mad:

The car is booked in for a 2 hour service slot ( it seems it needs this time to address this situation) on Tues & the service receptionist did not seem surprised at all by what was happening, so doesn't look as though I am the first to suffer this problem :(

It's a nice car, but I'm starting to wish now that I had gone for the petrol version & suffered the "allegedly" worse fuel consumption !

As an example today's drive was around 7 mile "country" roads then 7-8 mile motorway with 2-3 mile light urban on the last leg home about 17 mile round trip (water & oil temp at normal nice warm dry day) that had triggered regen on the last few hundred yards as I approached where I live, it then ran on for about 5 mins.
Out of the 580 miles so far traveled around 200 have been on motorway/dual carriageway & at least another 100 on "A" roads with the remainder being a mix of country & light urban with only 25 miles max in any significant "traffic".

As previously mentioned the dealer was completely aware of my typical driving profile & strongly recommended the diesel on the basis of better economy & me not needing the extra performance of the 1.4 TSI range.

Be interesting to see what happens on Tuesday as for a 2 hour slot they must be going to do something (hopefully)

D

[dcdick]

High mileage for diesels, maybe not, but significantly lower than average mileage for diesels is a valid point. I'm not talking about people disregarding the choice of diesel by saying things like "you'll never get your money back unless you're doing 20k miles a year" etc.

It is all about the DPF. You need a decent journey length a few times a week for the DPF to unclog. You've had your car for almost a month now and one of your first journeys was a 90 mile round trip, so you've averaged 18 miles a day excluding that one trip (for 550 miles total on the clock). If you're doing 5 miles here and 6 miles there on every trip then the DPF won't be getting a passive workout and will be trying it's best to do a forced regen a lot of the time you're out in it.

The argument doesn't apply to taxis as even though they do lots of short journeys, those journeys are accumulative - the taxi's engine doesn't have time to cool down between trips and so passive regen is going on all the time.

Forced regens make the car thirsty for those trips it's happening on. If the car is trying to go through on on nearly every trip then your mpg is going to suffer quite badly.

I don't think your situation with mpg will improve without intervention. If my assumption about your journeys is incorrect e.g. you do that mileage by fewer and longer trips rather than using the car daily and you regularly go at least 10 miles on a single trip doing motorway speeds (to get the engine temp up for a good few miles before your journey finishes) then the car is the problem, not your driving habits. In that case VW might be able to perform a warranty remap. Initial teething troubles with DPFs on TDIs are sorted for the 2.0 unit, not sure whether the same stands for the 1.6 unit.



My "average" journey could well be described as 10-15 miles made up of 3-4 mile journeys & 20-25 mile journeys with occasional 50+ mile runs, yearly mileage will be around 12-13k.
As the leasing cost was the same for 1.4 petrol & 1.6 diesel the fuel saving over the petrol using the published figures was significant enough to make my mind up as out & out performance was not a factor for me

I'm retired now (67) so the diesel seemed to fit my needs for economical motoring with a bit of "class/quality"

Now the bloody thing has seemingly filled it's filters up & is doing a regen almost all the time Aaaaargh....

D

[maisbitt]

DCDick: If your described round trip was done in quick succession, rather than split into 2 trips with the engine cooling right down in between then it should've been plenty to induce regen earlier than a few hundred yards from your home. It would seem then that your car definitely has something up with it. In 6 TDIs from new I have never seen the economy improve appreciably with miles, so don't let them fob you off with some miracle story of how economy will improve 30% once you have 10k miles on - it won't happen.

You should maybe keep an eye on your oil and water temps per journey, and it you're driving like miss daisy (because you're running it in gently) then the situation might improve when you drive it a little harder (car warms up quicker, prompting regen to kick in earlier into the journey). Or maybe you'll find the car is taking an age to warm up anyway.

Pre MK7 Golf TDIs seem to be quite easy to achieve the combined MPG, especially in the summer. Can't understand why the weight reductions, bluemotion tech and engine "improvements" don't seem to be resulting in appreciable gains. Might've been better off getting a 1.4GT with cylinder deactivation tech.

[dcdick]

DCDick: If your described round trip was done in quick succession, rather than split into 2 trips with the engine cooling right down in between then it should've been plenty to induce regen earlier than a few hundred yards from your home. It would seem then that your car definitely has something up with it. In 6 TDIs from new I have never seen the economy improve appreciably with miles, so don't let them fob you off with some miracle story of how economy will improve 30% once you have 10k miles on - it won't happen.

You should maybe keep an eye on your oil and water temps per journey, and it you're driving like miss daisy (because you're running it in gently) then the situation might improve when you drive it a little harder (car warms up quicker, prompting regen to kick in earlier into the journey). Or maybe you'll find the car is taking an age to warm up anyway.

Pre MK7 Golf TDIs seem to be quite easy to achieve the combined MPG, especially in the summer. Can't understand why the weight reductions, bluemotion tech and engine "improvements" don't seem to be resulting in appreciable gains. Might've been better off getting a 1.4GT with cylinder deactivation tech.

Thanks for your reply :D

I do drive "casually" ie not accelerating with too heavy a right foot in normal driving, but have noticed that the fuel consumption drops like a stone in even moderate acceleration & as you say in today's weather conditions I should be getting the best economy available. I really do think there's something not right here & I've been involved long enough in the "motor trade" when I was working not to be "fobbed off" by "techno babble" by the dealer staff. However I'll try not to pre-judge them until they have had the car in.
If it is struggling to hit 50 mpg on a warm dry day, what's it going to get on a cold wet February morning ? There has been a noticeable worsening in fuel consumption over the last 10/12 days which you could easily imagine is the DPF thing getting "choked up" & causing the protection systems to kick in.
Like you I can't see what all this weight reduction/blue motion tech & engine improvements has done to improve the car :(

I really am thinking that I should have gone for the 1.4 TSI as the Mk vi one I had for a couple of years returned around 45 mpg overall ( including one quite bad winter where I spent a long time in queue's travelling to & from work) during the time I had it as I recall (with no issues like this regen crap either)

D

[-M-]

Look at DPF information (http://www.vwaudiforum.co.uk/forum/showthread.php?147028-DPF-information&p=818126#post818126) for more info.

It sounds like the system is sooting up due to the temperture of the system not being met - I believe this to be because of the type of driving just not being suitable. You need to be driving in a certain way ie no stop starts, no town driving etc in order for the sytem to be at optimal temps otherwise more fuel gets used by regens.

[dcdick]

Look at DPF information (http://www.vwaudiforum.co.uk/forum/showthread.php?147028-DPF-information&p=818126#post818126) for more info.

It sounds like the system is sooting up due to the temperture of the system not being met - I believe this to be because of the type of driving just not being suitable. You need to be driving in a certain way ie no stop starts, no town driving etc in order for the sytem to be at optimal temps otherwise more fuel gets used by regens.

So the car now dictates the way in which I have to drive it ........:zx11:

Bloody thing will do what it's told or else, previous diesel car worked ok under the same conditions so this one should as well.............

Thanks for the link :D

D

[zollaf]

this is exactly why i keep older stuff going. my 80 does what i tell it to do, and certainly doesn't dictate anything to me.

[mcmaddy]

so what's going to happen with the gtd seeing as though it has stop/start on it??

[maisbitt]

so what's going to happen with the gtd seeing as though it has stop/start on it??

Press the deactivation button at the start of every journey or find a way with VAGCOM/VCDS to turn the bloody thing off. Only any good if you're choked in city traffic all the time, and if that's the way you drive (lots of stop-start urban journeys) then the DPF issues dictate you shouldn't have bought a TDI. Brake regen is a good idea, doesn't impede your driving style, but stop/start on a TDI? What a waste.

DCDick: have you ensured your ADC settings aren't making the car brake a lot of the time (for the car in front), impeding your economy? If my GTD can't crack 55mpg around the doors and 60mpg on a longer motorway journey i'll be disappointed.

My 170TDI Scirocco did 56mpg on a round trip to Hartlepool from North Shields today (65 miles), doing an indicated 75-80mph down the A19.

[-M-]

so what's going to happen with the gtd seeing as though it has stop/start on it??

Stop/start again will only activate under certain conditions - on cold starts it wont come on untill its at operating temps, then it will work but if A/C is on it wont as the compressor needs to run, if wipers are on it wont work as they will drain the battery quicker without the alternator running. On vehicles with stop/start an agm battery is fitted in order to deal with repeated starts etc.

[algarve]

Stop/start again will only activate under certain conditions - on cold starts it wont come on untill its at operating temps, then it will work but if A/C is on it wont as the compressor needs to run, if wipers are on it wont work as they will drain the battery quicker without the alternator running. On vehicles with stop/start an agm battery is fitted in order to deal with repeated starts etc. ....On the MK7 with the new thermal management set up it warms up quickly and by the way Stop/start is designed to function with both the A/C and the wipers on which it does, if there is a normal level of charge in the battery

[-M-]

....On the MK7 with the new thermal management set up it warms up quickly and by the way Stop/start is designed to function with both the A/C and the wipers on which it does, if there is a normal level of charge in the battery

... hence why I said under certain conditions.
Without the engine running the A/C compressor would not be driven unless an electric motor is fitted to the compressor like Touaregs and stop/start puts driver comfort over economy so would not cut in.

[dcdick]

Press the deactivation button at the start of every journey or find a way with VAGCOM/VCDS to turn the bloody thing off. Only any good if you're choked in city traffic all the time, and if that's the way you drive (lots of stop-start urban journeys) then the DPF issues dictate you shouldn't have bought a TDI. Brake regen is a good idea, doesn't impede your driving style, but stop/start on a TDI? What a waste.

DCDick: have you ensured your ADC settings aren't making the car brake a lot of the time (for the car in front), impeding your economy? If my GTD can't crack 55mpg around the doors and 60mpg on a longer motorway journey i'll be disappointed.

My 170TDI Scirocco did 56mpg on a round trip to Hartlepool from North Shields today (65 miles), doing an indicated 75-80mph down the A19.

The fact that "Stop Start" is fitted to the diesel cars says to me that these cars are suitable for use in "city" traffic as well as mixed driving. Going to be an interesting visit on Tues to the service department.
Even using the car in traffic I remain to be convinced of the benefits of "stop start"................. more suited to petrol models than diesel it would appear

D

[maisbitt]

The fact that "Stop Start" is fitted to the diesel cars says to me that these cars are suitable for use in "city" traffic as well as mixed driving. Going to be an interesting visit on Tues to the service department.
Even using the car in traffic I remain to be convinced of the benefits of "stop start"................. more suited to petrol models than diesel it would appear

D

I'm sure the primary reason for fitting this stop-start tech is to force the CO2 rating down. Given that lab testing to determine CO2 and economy "official" figures pretty much involves driving under the extreme end of "ideal" conditions, I doubt that the stop-start tech has much of a chance to work during these test conditions. Diesels are nowhere near as thirsty under idl;e as petrol cars are, hence taxi-drivers don't generally bother turning the engine off at Taxi ranks. The use of stop-start tech does imply city driving suitability, and although my driving habits (daily commute, annual mileage) haven't changed since owning the MK5 170TDI Golf (first golf with standard DPF), the way my 2 Sciroccos have driven since implies that the DPF regen is far less invasive than it used to be for someone that generally does 10+ miles on the majority of their single trips.

I do wonder why VAG went down the 1.6/2.0 route for TDI rather than using a single engine at various stages of tuning like BMW do, the economy gains of a 1.6TDI seem negligible over the 2.0. Perhaps the 1.6 unit is still requiring some tweaks as it is a lot younger than the 2.0 unit.

[dcdick]

I'm sure the primary reason for fitting this stop-start tech is to force the CO2 rating down. Given that lab testing to determine CO2 and economy "official" figures pretty much involves driving under the extreme end of "ideal" conditions, I doubt that the stop-start tech has much of a chance to work during these test conditions. Diesels are nowhere near as thirsty under idl;e as petrol cars are, hence taxi-drivers don't generally bother turning the engine off at Taxi ranks. The use of stop-start tech does imply city driving suitability, and although my driving habits (daily commute, annual mileage) haven't changed since owning the MK5 170TDI Golf (first golf with standard DPF), the way my 2 Sciroccos have driven since implies that the DPF regen is far less invasive than it used to be for someone that generally does 10+ miles on the majority of their single trips.

I do wonder why VAG went down the 1.6/2.0 route for TDI rather than using a single engine at various stages of tuning like BMW do, the economy gains of a 1.6TDI seem negligible over the 2.0. Perhaps the 1.6 unit is still requiring some tweaks as it is a lot younger than the 2.0 unit.

I was wondering if the 1.6 currently used is just about at the end of it's usable life & is just being held onto for the tax banding.

It seems to me it's the same engine that was introduced in 1991 as TDI then further improved with "common rail" fuelling in 2007, or is the 2007 version truly a new engine ?
Are there tax advantages in running the 1.6 TDI over the 2.0 ?

As you say there seems to be almost no "real life" differences in economy between the 148 bhp 2.0 & the 103 bhp 1.6 :confused:

Renaults version of the 1.6 TDI in it's "standard" form puts out around 140 bhp & goes a lot higher in the sporty models, seems a bit strange that the VW engine is comparatively low powered compared to others......or is it held down to keep a clear difference between the 2.0 models ?

D

[maisbitt]

dcdick: I think you're confusing your 1.6TDI with the original TDI engine, which is the 1.9. The 1.6TDI has only been around since 2009 and has only ever been available with common rail fuelling and a DPF in 2 outputs that I know of (90PS and 105PS).

The 2.0 came in during 2004 with PD fuelling, and common rail fuelling came later (2008?). The 2.0 TDI 170 PD on the MK5 Golf (late 2006) was the first TDI to have a DPF (the 140 version of it didn't have it). You can easily tell a 140TDI from a 170TDI on a MK5 Golf as, on the 140, the relatively sooty output is hidden with the tailpipes discharging downward from behind the rear bumper. On the cleaner 170 you get chrome tailpipes poking out through the bumper for all to see.

You have the most newly developed TDI engine out there. I would say that it is held back so as not to compete with the 2.0 lump, or perhaps the 2.0 lump is more economical and has a lower CO2 output at 140PS than a 1.6 would be if it were tuned to that output.

[dcdick]

dcdick: I think you're confusing your 1.6TDI with the original TDI engine, which is the 1.9. The 1.6TDI has only been around since 2009 and has only ever been available with common rail fuelling and a DPF in 2 outputs that I know of (90PS and 105PS).

The 2.0 came in during 2004 with PD fuelling, and common rail fuelling came later (2008?). The 2.0 TDI 170 PD on the MK5 Golf (late 2006) was the first TDI to have a DPF (the 140 version of it didn't have it). You can easily tell a 140TDI from a 170TDI on a MK5 Golf as, on the 140, the relatively sooty output is hidden with the tailpipes discharging downward from behind the rear bumper. On the cleaner 170 you get chrome tailpipes poking out through the bumper for all to see.

You have the most newly developed TDI engine out there. I would say that it is held back so as not to compete with the 2.0 lump, or perhaps the 2.0 lump is more economical and has a lower CO2 output at 140PS than a 1.6 would be if it were tuned to that output.

Interesting with VW diesel engines............I distinctly remember a 1.6 TDI coming in 1991 model year called the "eco diesel" that was also fitted to Passats & Transporters I believe, but the 1.9 was the main engine at that time as you say.
I had a quick look & it seems that the 1.6 tdi was reintroduced as a "new" engine in 2008 when the "blue motion" models where also announced, the Mk 7 model I have is the "improved" version that weighs less & is allegedly more economical.
I'll find out tomorrow I suppose when the dealer gets to check it out.............. I'm convinced there has to be something wrong with this "premium" new model diesel that gets less mpg than my mates 10 year old Peugot 2.0 diesel that has well over 100,000 on the clock (55 + mpg & it is thrashed around as he's "old school diesel" )

The mpg seems to be gradually worsening which is I presume is due to the "sooting up" of the filters & the subsequent "regen" cycles that are now a daily part of my driving :(

D

[dcdick]

SHOCKED !!!!!

Been to dealers & had a very revealing discussion with the service supervisor........:(

It seems that 50 mpg in "normal" driving is the norm so far for the "new" 1.6 TDI (Blue motion technology)............55 mpg is a good result with up to around 60 mpg on a cruise down the motorway.
And it does seem that the standard 2.0 TDI is more economical.
Also confirmed was my belief that after a few '000 miles mpg will not improve by a significant amount.
The emissions control & DPF technology is cited as the reason for the poor economy against expectations of good economy from this "new" diesel engine
Further, any less than a 15 mile journey does not give the DPF stuff enough time to work "passively" & that will explain the regen working after switch off.
The long term result of which will be a shortening of the DPF filters service life & will require replacement that will not be covered by VW warranty.
When asked why a stop-start system is fitted the reply was "for driver convenience"

So, in summary if I don't do a weekly non stop run of at least 50/60 miles, the filter will gradually clog until it can't be purged with regen & dealer forced regens which will then require it to be replaced.

15 mile minimum journey or the car goes into regen mode (using more fuel) !!! WHAAAAAT ?????????

Going to try the lease company to see what they can or will do about this. I can send it back of course, but that will cost a fair bit of money I would imagine

D

ps.............Current fuel economy is around 48 mpg which seems to be directly related to the amount of regens..............down from around 54 before the regens started 2 weeks ago.

[zollaf]

i am so chuffed and delighted that 20 years of diesel technology and improvements have resulted in such amazing progress.
my 19 year old audi 80 will only do 46 average on short local journeys with 55 on a run down the motorway at 80. i hate to think what it would do if i stuck to 56 mph. the stop/start fitted is totally driver dependent and works when i want it to, and i wish i had one of these dpf's, but i cut it out and sold it for scrap.
you must be so happy that you car is so much better than mine :)

[dcdick]

i am so chuffed and delighted that 20 years of diesel technology and improvements have resulted in such amazing progress.
my 19 year old audi 80 will only do 46 average on short local journeys with 55 on a run down the motorway at 80. i hate to think what it would do if i stuck to 56 mph. the stop/start fitted is totally driver dependent and works when i want it to, and i wish i had one of these dpf's, but i cut it out and sold it for scrap.
you must be so happy that you car is so much better than mine :)

ha, ha ......................... your dead right, modern tech stuff has certainly failed me. Wish I still had my mk iv diesel :(

D

[dcdick]

Here's an interesting statement. The official word on current emissions/mpg testing

How are official mpg figures calculated?

There have been various standardised tests to calculate the miles per gallon (mpg) figure for each car over the years. The current method (monitored by the Department of Transport) sees cars being tested in a laboratory.
The car is fixed on a set of rollers known as a rolling road, and a series of drills including braking and accelerating are performed; these are designed to replicate types of driving.
The exhaust gases released are measured using special equipment. From this, the emissions ratings are calculated as well as the fuel economy (mpg figure).
This test involves two parts:
The Urban Cycle
This begins with a cold engine start; the car is stopped and started a number of times to replicate town driving. The maximum speed is 30mph and the journey lasts two and a half miles.
The Extra Urban Cycle
This lasts for 4.3 miles at speeds of up to 75mpg designed to replicate out-of-town driving.

So the 1.6 TDI can get way past 70 mpg on a 4.3 mile run on the rollers without affecting the DPF when "on test". This ties in well with my findings, as in my case the consumption was fine for the first couple of hundred miles or so until the "soot" started to affect the DPF.

The plot thickens ;)

D

[zollaf]

can anyone else see a fundamnetal flaw in testing a cars mpg in a lab on a rolling road. what about wind resistance ? why not just drive the thing for a bit and see what you get, like in the good old days.

[dcdick]

can anyone else see a fundamnetal flaw in testing a cars mpg in a lab on a rolling road. what about wind resistance ? why not just drive the thing for a bit and see what you get, like in the good old days.

That would be the easy way :confused:.......................sadly, in today's bureaucratic nightmare that are the regulations about pollution, every test has to be repeatable under controlled circumstances !

Talking of the good old days I remember setting cars up with a timing light & feeler gauges then going to the back to have a quick "sniff" of the exhaust to check if it was running "rich". Seems like a different world :(

D

[Pommyboi]

can anyone else see a fundamnetal flaw in testing a cars mpg in a lab on a rolling road. what about wind resistance ? why not just drive the thing for a bit and see what you get, like in the good old days.

because if you did that how would you compare different cars? That is all the testing is about, not what you will get in real life but how your car compares to another.

[vc-10]

You should be getting more than 50mpg from a 1.6 TDI- I got a ZipCar 1.6 TDI Golf 6, on an 11 plate with no Bluemotion stuff, and it gave me 50mpg according to the computer when I was absolutely thrashing it. And I can't imagine that a ZipCar Golf lives an easy, comfortable life...

I do wonder if the injectors VW are using aren't really capable of being used with 'real world' fuel, with impurities.

[-M-]

You should be getting more than 50mpg from a 1.6 TDI- I got a ZipCar 1.6 TDI Golf 6, on an 11 plate with no Bluemotion stuff, and it gave me 50mpg according to the computer when I was absolutely thrashing it. And I can't imagine that a ZipCar Golf lives an easy, comfortable life...

I do wonder if the injectors VW are using aren't really capable of being used with 'real world' fuel, with impurities.

The model you describe would be CR TDi with dpf so it would indeed have "bluemotion" technology in order to comply with EU emission targets.

Getting back on topic - the OP's car is still new and mpg will improve with mileage - but with dpf regens being more frequent due to the use of vehicle it will use more fuel.

[vc-10]

Nope, it didn't have Bluemotion Technology. Bluemotion Technology is the regenerative braking and stop/start. It was made standard on the Mk.7, but on the Mk.6 it was optional on the SE/Match 1.6 TDI, and the 2.0 TDI. It did have a DPF though.

[dcdick]

- the OP's car is still new and mpg will improve with mileage - but with dpf regens being more frequent due to the use of vehicle it will use more fuel.

That's the issue, I should be able to use the car any way I choose..............pop down the shops or cruise down the motorway :mad:

"Old style" diesels are quite happy doing short journeys in town as well as running down a motorway.
The relentless move towards "green" cars is forcing diesel engines to work in ways that they are not comfortable with yet........... and the DPF filter system seems to be the culprit in this.

Will the consumption get better with miles driven ? I would be very surprised to see more that 4-5% increase in economy but, the way this engine works anything could happen :confused:

On a run today of around 25 mile each way the car returned 51 mpg out ward & 60 mpg on the return............ (80% motorway 20% A roads no traffic problems, cruising around 65-70 on Mway 4 hr gap between runs so engine starting from "cold" both times).
There did not appear to be any significant differences in gradients etc... each way.
Could it be that the DPF was "cleaned out" on the first part of the journey & the increase of mpg on the return miles was due to the filter having free flow ?

I'll be fuelling with a "premium" version of Shell/BP tomorrow so will see what happens over the next few weeks with supposedly cleaner/better fuel

D

[-M-]

Nope, it didn't have Bluemotion Technology. Bluemotion Technology is the regenerative braking and stop/start. It was made standard on the Mk.7, but on the Mk.6 it was optional on the SE/Match 1.6 TDI, and the 2.0 TDI. It did have a DPF though.

Bluemotion was originally used to denote special models in the VW range ie golf tsi, golf gti, golf bluemotion. Then it was used to denote the use of DPF on any diesel models VW. Bluemotion technology is used on all models now petrol and diesel.

[-M-]

That's the issue, I should be able to use the car any way I choose..............pop down the shops or cruise down the motorway :mad:

"Old style" diesels are quite happy doing short journeys in town as well as running down a motorway.
The relentless move towards "green" cars is forcing diesel engines to work in ways that they are not comfortable with yet........... and the DPF filter system seems to be the culprit in this.

D

If you recall also when old school diesels were driven on short journeys there used to be a big cloud of smoke when you booted it from time to time with all that NOx gas going into the atmosphere - unfortunately this isnt acceptable any more and cars need to have as much of the harmful gasses eliminated. The DPF is designed to do this but needs to be at a high temp in order to do so. The environment is a very important issue and affects us all - I for one dont like holes in the ozone layer so technology has to move forward to reduce the damage thats caused.

Diesel engines are more than capable of operating like this with great comfort as long as the operating conditions are met - unfortunately sales have to push to meet targets and I believe that they should have sold you on a petrol version rather than a diesel as your driving requirements do not match that of the car and these days it is essential to match these 2 requirements together as modern diesels do not allow for you to drive it how you wish.

[dcdick]

If you recall also when old school diesels were driven on short journeys there used to be a big cloud of smoke when you booted it from time to time with all that NOx gas going into the atmosphere - unfortunately this isnt acceptable any more and cars need to have as much of the harmful gasses eliminated. The DPF is designed to do this but needs to be at a high temp in order to do so. The environment is a very important issue and affects us all - I for one dont like holes in the ozone layer so technology has to move forward to reduce the damage thats caused.

Diesel engines are more than capable of operating like this with great comfort as long as the operating conditions are met - unfortunately sales have to push to meet targets and I believe that they should have sold you on a petrol version rather than a diesel as your driving requirements do not match that of the car and these days it is essential to match these 2 requirements together as modern diesels do not allow for you to drive it how you wish.

With you 100% on pollution, although diesel cars are not the big problem they should be made to run as clean as possible.

The issue of choosing petrol or diesel............ when choosing the car I discussed my use of the car with the "advisor" as they call them these days & his response was that the DPF & it's workings would not be a problem. The car was bought purely on the basis of economy..................the published economy figures do not really matter but the 25% better economy of the diesel over the equivalent petrol (1.4 TSI ) is the whole point.

Currently the economy is around 5/10% better than the petrol & this clearly makes this 1.6 diesel "not fit for purpose".

The lease company insist I leave it until 2,000 miles, then they will "fix it" which I suppose means allow me to change to something like the petrol TSI without the financial penalty I will incur by changing/handing the car back now.

VW dealer insist the car has no faults after testing it last week. The service "senior supervisor" has said (off the record) that I do too many short journeys & should have got a petrol one as the current TSI economy when driven carefully is very close to the diesels (my 1.6 TDI in particular )

The annoying thing for me really is that the car is so bloody good, apart from the mpg that I would like to keep it

D

[Gerryf]

Hi D, you should take the lease Company up on their offer because you're going to be plagued with bother unless your usage of the car changes.

I use a car very similar to you and I can honestly say the petrol TSI is nearly as good on fuel as my previous diesel....3 mpg difference in congested London....sure ! the diesel shines on the Motorway but it's rare I use Motorways.

Don't go too hard on the Salesman because your weekly mileage suggests you should be fine with a diesel but it's all those short journeys that's killing your mpg figures.

Horses for courses eh :)

[DW58]

Sorry to hear of your problems - I almost ordered a Golf SE 2.0TDI on Friday - I do lonts of short(is) journeys, damned glad I opted for the SE 1.4TSi after reading this.

Hope you get this sorted soon

[dcdick]

Hi D, you should take the lease Company up on their offer because you're going to be plagued with bother unless your usage of the car changes.

I use a car very similar to you and I can honestly say the petrol TSI is nearly as good on fuel as my previous diesel....3 mpg difference in congested London....sure ! the diesel shines on the Motorway but it's rare I use Motorways.

Don't go too hard on the Salesman because your weekly mileage suggests you should be fine with a diesel but it's all those short journeys that's killing your mpg figures.

Horses for courses eh :)

Don't know about being too hard on the salesman........he said in front of a witness (my wife) when asked directly about the DPF issues that the car would take care of that sort of thing automatically. Yes it does, but drinks diesel doing it :(

Should he have suggested I get the TSI model.............................. ? all he did was point at the mpg figures in the brochure & I still have the brochure where he has underlined the mpg for petrol/diesel.

This bloody car should operate efficiently in traffic & motorways as well as in short or longer journeys................. it's 2013 & we are talking about a £20,000 (or more) car not a dodgy Asian import. Grrrrgh!!!

Fuelled with Shell premium diesel today that costs 7p per liter more then standard Shell V Power, see what happens now ;)

D

[dcdick]

Sorry to hear of your problems - I almost ordered a Golf SE 2.0TDI on Friday - I do lonts of short(is) journeys, damned glad I opted for the SE 1.4TSi after reading this.

Hope you get this sorted soon

You may just have done the right thing there :D .......................... however the 2.0 TDI seems to be a bit more tolerant of "shorter" journeys.

Good luck with the car

D

[vc-10]

Bluemotion was originally used to denote special models in the VW range ie golf tsi, golf gti, golf bluemotion. Then it was used to denote the use of DPF on any diesel models VW. Bluemotion technology is used on all models now petrol and diesel.

Cars badged 'Bluemotion' are the full on eco versions- lowered, higher gearing, and bodykit on some. 'Bluemotion Technology' is a badge put on regular cars, which are fitted with stop/start and regenerative braking, but not the other changes for the 'Bluemotion' vehicles. It doesn't mean DPF- all cars with the CR diesels have DPFs, no matter what the badges are. The Mk.5 Bluemotion Golf had a DPF, but it was also slightly lowered and geared higher, so it had a higher MPG. They had adverts about the DSG gearboxes being part of their 'Bluemotion' thinking- but they're not 'Bluemotion Technology' (although, obviously, some cars with BMT have DSG gearboxes).

For the Mk.6 Golf (like I had), it was available with the 1.6 CR TDI and the 2.0 CR TDI. Both these engines were available with 'Bluemotion Technology' and badged as such, or the 1.6 TDI was also in the 'Bluemotion' Golf. This was the 1.6 TDI with BMT, but lowered, given higher gearing, bodykit etc. I was pointing out that I had a 1.6 TDI *without* BMT, and got 50mpg, and I'd expect a Mk.6 *with* BMT to get a better MPG (if only slightly, the way I was driving it) and a Mk.7 1.6 TDI to be even better as it's lighter. All Mk.7 Golfs are 'Bluemotion Technology', but not all Mk.6 Golfs. 'Bluemotion Technology' is still only used on cars with stop/start- and remains a cost option on some (the Up, for example).