Hello again,

. Mine was regenerating every 250 ish miles early doors and then became more frequent. So, I probably had 7 or 8 in 1500 miles!! Mind you, I think the distance I cover and the driving conditions are such that the right conditions for a DPF regeneration seem to occur at the end of the journey and I'm not sure they all finished before the car was turned off. Might explain the number.

I would expect your regen to be similar to mine. Mine regens roughly every 120 miles. Usually it never gets interrupted as I do long journeys. If it does fail to complete a regen on the way home then it starts again next time I drive it once the engine has warmed up.

If you were at speed on a motorway then its possible to be unaware of the regen in progress. After many miles I know every knock and rattle of my engine so I know straight away when it does it.

Glad to hear you have had some effective changes to your mpg. If its possible to assume the same improvement of mpg after running in as mine you will maybe get an extra 6mpg.

Who knows, maybe they will have yet another software update for you in the future....

As for the lower idle. It is possible that this is a cheeky method to give a reduced combined mpg. The Euro tests include some idling and lower rpm wil help the figures. On the Greenline 2 the stop start system allows them to claim 4 mpg on the combined.

I hope you can start to enjoy the car to the full now. I imagine it has been very frustrating.

I would expect your regen to be similar to mine. Mine regens roughly every 120 miles. Usually it never gets interrupted as I do long journeys. If it does fail to complete a regen on the way home then it starts again next time I drive it once the engine has warmed up.

If you were at speed on a motorway then its possible to be unaware of the regen in progress. After many miles I know every knock and rattle of my engine so I know straight away when it does it.

Glad to hear you have had some effective changes to your mpg. If its possible to assume the same improvement of mpg after running in as mine you will maybe get an extra 6mpg.

Who knows, maybe they will have yet another software update for you in the future....

As for the lower idle. It is possible that this is a cheeky method to give a reduced combined mpg. The Euro tests include some idling and lower rpm wil help the figures. On the Greenline 2 the stop start system allows them to claim 4 mpg on the combined.

I hope you can start to enjoy the car to the full now. I imagine it has been very frustrating.

It has been very frustrating. I was around town today for no more than about 10 miles in total and the computer reckons it did about 47-48mpg over the various journeys. This is by some distance the best I've ever seen for these sort of short journeys. Can't wait until Tuesday when I can try it on my normal longer journeys. Even if the computer is a couple of mpg over, that'll still do me for around town, especially at the moment if it may get better. Best I'd seen before around town was about 35mpg. So, if Tuesday goes well, I'll sit back, congratulate my dealership (whatever they or Skoda did) and enjoy the driving.

It has been very frustrating. I was around town today for no more than about 10 miles in total and the computer reckons it did about 47-48mpg over the various journeys. This is by some distance the best I've ever seen for these sort of short journeys. Can't wait until Tuesday when I can try it on my normal longer journeys. Even if the computer is a couple of mpg over, that'll still do me for around town, especially at the moment if it may get better. Best I'd seen before around town was about 35mpg. So, if Tuesday goes well, I'll sit back, congratulate my dealership (whatever they or Skoda did) and enjoy the driving.

Excellent news! Hope your care continues to improve over time.

Just back from a trip to Legoland. Just under 400 miles since Friday and the trip home recorded 63.3 mpg driving at around 65-70 no traffic jams.

I didn't have a full tank going and it is showing just under a quarter remaining.

Very pleased as this was the longest trip to test it out.

MikeHart

How is your car's economy now?

MikeHart

How is your car's economy now?

Hello again,

Well, it gets more interesting. The mpg has definately gone up, but not as much as the computer suggests. Before the software upgrade, the computer was pretty much spot on the money against fill to fill checks. Now, it's registering something like 3-4mpg higher than fills show. Don't know if this is the software change or what. However, the last tank made 52mpg, the general trend is definately up and that's at least a 3-4mpg increase on the previous tank, so things are better. Have to wait and see what happens with future ones. I normally do a tank about every 1.5 weeks, so it'll take a while.

Whilst I appreciate engines take a little time to loosen up, this one seems quite extreme. If an engine regularly takes as long as these to reach peak mpg (at least 10-20k miles), I do feel they should publish two figures. An initial and a 10 or 20k one to give people more information. Otherwise, using their logic, I could advertise and sell my house for say £350k today whilst the market value is only £300k on the ground it should reach £350k in two years time once they've run it in!! Doesn't make sense and is fundamentally false advertising. This is especially true when other manufacturers cars seem to reach their mpg figures (and the max) much, much quicker. Indeed, within a couple of thousand miles if not immediately.

Hello again,

Well, it gets more interesting. The mpg has definately gone up, but not as much as the computer suggests. Before the software upgrade, the computer was pretty much spot on the money against fill to fill checks. Now, it's registering something like 3-4mpg higher than fills show. Don't know if this is the software change or what. However, the last tank made 52mpg, the general trend is definately up and that's at least a 3-4mpg increase on the previous tank, so things are better. Have to wait and see what happens with future ones. I normally do a tank about every 1.5 weeks, so it'll take a while.

Whilst I appreciate engines take a little time to loosen up, this one seems quite extreme. If an engine regularly takes as long as these to reach peak mpg (at least 10-20k miles), I do feel they should publish two figures. An initial and a 10 or 20k one to give people more information. Otherwise, using their logic, I could advertise and sell my house for say £350k today whilst the market value is only £300k on the ground it should reach £350k in two years time once they've run it in!! Doesn't make sense and is fundamentally false advertising. This is especially true when other manufacturers cars seem to reach their mpg figures (and the max) much, much quicker. Indeed, within a couple of thousand miles if not immediately.

Problem as I see it is that the car companies have absolutely no choice in the matter. European law dictates they all must publish the figures based on everyone carrying out identical tests. They could publish real world figures but then this reflects badly on them. Unless every company is made by law to carry out real world tests then you just have to take the inflated mpg figures for what they are.........utter tripe. Posting two figures would be nice, it would also probably be illegal under EU law as its not generated in an 'approved' test.

I agree with what you are saying, but common sense and honesty sadly isnt permitted under EU regulation 55/47B.......yes I made that up.

I will add that my car has 13000 miles on it from new and the mpg has stabilised. Oddly the trip computer now reads accurately whereas previously it was over reading by about 5 mpg. No idea why.

The Fabia vRS (Mk1) I had took about that long to get the good numbers. Also winter diesel is WAY lower on MPG in my experience (for me up to 10mpg difference was not an exception, but when I lived in the UK I didnt hang about too much;))

Hi Mike, thanks for keeping up with publishing all the figures for your new car. I'm so glad you are getting some improvement.

I've worked for some different franchises over the years, and I can tell you they all get the same complaints. But VW/Skoda seems to get far fewer problems in this area of fuel economy normally, although I've never worked for Skoda or VW, I rely on my technician friends still in the trade to keep me up to date. All engines take at least 10k to produce best power and best economy and some even longer. That's a fact of life and actually, it's always been about that even if we think our engine of 10 years ago was better. But now, due to tighter tolerances there is probably a more noticeable effect of fuel economy in the early stages of running in. I've been on the forums for other makes, and most manufacturers are being shouted at by their customers about fuel economy from what I can see. It seems to be Euro V is having quite an effect. It's an area totally new to the manufacturers and is proving difficult in practice to meet in the early days when the engines are tight. It may well be we will see some modification to the wording in the car handbooks to make this plain in future.

VW/Skoda engines are superior in build and quite often design too. You can still be driving your Skoda engine in 20 years time without a problem because of the quality. People say to me "there can't be much difference can there?". Well, actually there is and I speak from experience of working on a variety of engines. Your engine meets stringent manufacturer processes and is put together using the latest techniques. I've been around several engine plants over the years and the difference in manufacturing processes is stark. VW engines use pretty much the best methodology and dis-guard their machine tools early rather than squeezing out another reaming of the bores to a cylinder block before throwing it away. That alone makes a huge difference to the quality of your engine. So enjoy for many years! Keep post if you can Mike, your information is very useful. Thanks mate!

Edited 13 November, 201015 yr by Estate Man

Been following this with interest as my 1.6 CR Tdi Fabia Elegance Estate, which has now reached 3000 miles since delivery in July, is averaging 48 mpg (spreadsheet), which agrees with the car computer (memory 2).

My excellent dealer, in Cornwall, had the car in the workshop last week for a day, to investigate my complaints of poor fuel consumption & surging. The tech said the engine management software version V18.42.0 was current & no diagnostic faults were found.

On their test drives, on the flat, they were achieving 60-70 mpg ( trip memory 1) at speeds between 50 & 70 mph. It was suggested, that frequent local trips around the more hilly terrain near my home in Tavistock, were probably significant & a few longer journeys were needed, to improve the average mpg. The surging, as others have stated, is an anti stall device & changing down a gear, would resolve the issue.

My observations are:-

My previous car a Fabia 1.9tdi, which I owned for 8 years, turned in 55-58 mpg month after month, with similar usage patterns. So I’m not lead footed.

On the test day, a 35mph easterly gale was blowing. Were the test drives conducted down wind only?

The courtesy car from the garage, was a new Fabia Scout Estate 1.6 CR Tdi, with only 500 miles on the odometer. Using this on the 48 mile journey home (mostly dual carriageway), the Scout was turning in 58mpg heading directly into the gale. My own car, on the same journey, in the same conditions, later on the day, struggled to reach 47mpg.

I had checked tyre pressures were ok on both cars which were also both running on Texaco diesel. Of course I have no idea if the Scout fuel computer was optimistic or running different engine software.

Before I go back to the dealer with the above observations, perhaps Mike Hart (& any others who have had updated software on their 1.6 CR’s), could tell me their engine software version numbers.

Thanks

Been following this with interest as my 1.6 CR Tdi Fabia Elegance Estate, which has now reached 3000 miles since delivery in July, is averaging 48 mpg (spreadsheet), which agrees with the car computer (memory 2).

My excellent dealer, in Cornwall, had the car in the workshop last week for a day, to investigate my complaints of poor fuel consumption & surging. The tech said the engine management software version V18.42.0 was current & no diagnostic faults were found.

On their test drives, on the flat, they were achieving 60-70 mpg ( trip memory 1) at speeds between 50 & 70 mph. It was suggested, that frequent local trips around the more hilly terrain near my home in Tavistock, were probably significant & a few longer journeys were needed, to improve the average mpg. The surging, as others have stated, is an anti stall device & changing down a gear, would resolve the issue.

My observations are:-

My previous car a Fabia 1.9tdi, which I owned for 8 years, turned in 55-58 mpg month after month, with similar usage patterns. So I’m not lead footed.

On the test day, a 35mph easterly gale was blowing. Were the test drives conducted down wind only?

The courtesy car from the garage, was a new Fabia Scout Estate 1.6 CR Tdi, with only 500 miles on the odometer. Using this on the 48 mile journey home (mostly dual carriageway), the Scout was turning in 58mpg heading directly into the gale. My own car, on the same journey, in the same conditions, later on the day, struggled to reach 47mpg.

I had checked tyre pressures were ok on both cars which were also both running on Texaco diesel. Of course I have no idea if the Scout fuel computer was optimistic or running different engine software.

Before I go back to the dealer with the above observations, perhaps Mike Hart (& any others who have had updated software on their 1.6 CR’s), could tell me their engine software version numbers.

Thanks

I was reading a different posting on this forum regarding the 1.6 cr surging. The chap posted a link http://www.autoexpress.co.uk/carreviews/firstdrives/235775/vw_polo_16_tdi.html

It would be very interesting reading for the 1.6 cr drivers and may give some support to garage claims as lets face it, the cars are the same. Just scroll down to the highly illuminating comments.

Edited 14 November, 201015 yr by raisbeck

Thanks for posting this interesting Auto Express thread. I have a 1.6 CD TDI 105 with 1800 miles on, always run on Shell Regular Diesel, and an overall average mpg of 47, plus the surging problem. Consumption seems to vary with no pattern. Best I have seen has been a slow B road trip of 12 miles with 62mpg, but a gentle mixed cross country trip this week gave just under 50mpg. Hard to get even 45 on a round 10 mile trip into the local small town. I keep hoping things are going to improve, but having read this thread it seems that this is a more general problem. I've not visited the dealer yet.

It would be interesting to get more reports, especially from people who are not having any problems, so please post if you have a 1.6 CD TD! I previously had a Fabia 1.9TDI, bought new, which regularly did 52mpg at an indicated 80mph on the motorway from day 1. My 2.0D Jaguar X Type is just back from a brisk 1100 mile trip to France with 4 up and luggage where it averaged 46.8mpg!

I've been prompted by the request for more 1.6TDI owners to share their experiences .I've been following this thread and a lot of the comments reflect my experience. I have a low mileage 2009 1.6 TDI MK6 and I've been disappointed with the the fuel consumption ever since I took delivery. I appreciate it will get better as the mileage increases but even with economy style driving the best I can get is 56mpg on a favourable long run . i.e. no hold-ups or excessive wind and cruising at 65-70 mph on dual carrigeways or motorways. I don't suffer any surges - quite the opposite ! I suffer from stalls !

Under similar conditions I can get 60 mpg from a 2010 Octavia estate 1.9 TDI with only a few hundred miles to it's credit.

If anyone knows of any software update I'm sure a lot of us would be very interested.

Hi I am starting to wonder if this purchase is a good thing,I may stop the purchase of my 1.6cr tdi fabia,this engine does not make me feel very good the write ups are terrible I have not had the build date yet,is there anyone out there happy with their purchase of the cr 1.6 engined fabia,its a lot of money for a crap engine,thinking maybe a bmw 1 series instead,all I can see on the vw engine is a lot of negatives what should we do

I have found that my fuel comsumption is slowly improving and the past week has been significantly better. It improves if I dont actually watch the computer and just drive normally!

Once a month I drive to work for a week which is a distance of 15 miles each way between Hythe and Ashford. I have found that if I use a route from Ashford using less sets of traffic lights, the comsumption improves as the car warms quickker. (I realise that this isnt always possible for everyone)

I do find the car impressively refined and gutsy when needed with bags of torque. Its just a shame the consumption hasnt been as significant as Skoda claims. I do find it relatively easy to get upto 56 mpg these days but its nowhere near 68mpg!

The car has done nearly 1600 miles.

Grahame

Problem as I see it is that the car companies have absolutely no choice in the matter. European law dictates they all must publish the figures based on everyone carrying out identical tests. They could publish real world figures but then this reflects badly on them. Unless every company is made by law to carry out real world tests then you just have to take the inflated mpg figures for what they are.........utter tripe. Posting two figures would be nice, it would also probably be illegal under EU law as its not generated in an 'approved' test.

I agree with what you are saying, but common sense and honesty sadly isnt permitted under EU regulation 55/47B.......yes I made that up.

I will add that my car has 13000 miles on it from new and the mpg has stabilised. Oddly the trip computer now reads accurately whereas previously it was over reading by about 5 mpg. No idea why.

Hello again,

Whilst I appreciate the need to have some sort of standardised test to try and prevent all the messing around that car companies would do otherwise, my main issue isn't the consumption difference from book per se, but that some companies expect engines to give their best mpg almost from new, whilst others (VW for instance it would appear), expect it to take a considerable period of time. I assume there's nothing particularly different about how VW make and engine and say Toyota, so I don't see why it should take a VW engine 10-20k miles to reach best mpg, whilst Toyota do it from day one. Maybe I just got lucky with the previous car. Others on here suggest VW engines are highly variable as the mpg from start seems to vary wildly.

Thanks,

Mike

Been following this with interest as my 1.6 CR Tdi Fabia Elegance Estate, which has now reached 3000 miles since delivery in July, is averaging 48 mpg (spreadsheet), which agrees with the car computer (memory 2).

My excellent dealer, in Cornwall, had the car in the workshop last week for a day, to investigate my complaints of poor fuel consumption & surging. The tech said the engine management software version V18.42.0 was current & no diagnostic faults were found.

On their test drives, on the flat, they were achieving 60-70 mpg ( trip memory 1) at speeds between 50 & 70 mph. It was suggested, that frequent local trips around the more hilly terrain near my home in Tavistock, were probably significant & a few longer journeys were needed, to improve the average mpg. The surging, as others have stated, is an anti stall device & changing down a gear, would resolve the issue.

My observations are:-

My previous car a Fabia 1.9tdi, which I owned for 8 years, turned in 55-58 mpg month after month, with similar usage patterns. So I’m not lead footed.

On the test day, a 35mph easterly gale was blowing. Were the test drives conducted down wind only?

The courtesy car from the garage, was a new Fabia Scout Estate 1.6 CR Tdi, with only 500 miles on the odometer. Using this on the 48 mile journey home (mostly dual carriageway), the Scout was turning in 58mpg heading directly into the gale. My own car, on the same journey, in the same conditions, later on the day, struggled to reach 47mpg.

I had checked tyre pressures were ok on both cars which were also both running on Texaco diesel. Of course I have no idea if the Scout fuel computer was optimistic or running different engine software.

Before I go back to the dealer with the above observations, perhaps Mike Hart (& any others who have had updated software on their 1.6 CR’s), could tell me their engine software version numbers.

Thanks

Hello and welcome to this thread,

I'm afraid I don't know what the software version is, other than it was fresh out about 3-4 weeks ago. I don't believe anyone said the actual version number in my earshot. If someone can tell me how to identify it from the car, I'll happily do so for you. From my own experience, I would suggest a couple of things. Give the engine a really good boot now and then does seem to help increase mpg. This is as suggested by Estateman. Don't know if you get the opportunity, but I tend to use the exit from roundabouts and get to 70 in 3rd which is somewhere between 3500 and 4000 rpm. The mpg returned (according to the computer) does seem to vary wildly and for no obvious reason. It's certainly a bit lower when the temperature is colder, but even at the same temperature, I've had it vary wildly for no obvious reason. On one occasion, I did have to use an alternative route home due to traffic congestion and this resulted in a lower average speed, which achieved considerably more mpg. Basically, my car doesn't seem to like doing 70!! Something like 40-50 seems the best mpg speed. I have started keeping a table of all the variables I can get from the computer for each journey to try and establish some factors. When I have a few more, I'll put it up here. I've also found that immediately after a DPF, the mpg seems to go down. This is true of two, so we'll have to see if this trend continues.

Thanks,

Mike

I was reading a different posting on this forum regarding the 1.6 cr surging. The chap posted a link http://www.autoexpress.co.uk/carreviews/firstdrives/235775/vw_polo_16_tdi.html

It would be very interesting reading for the 1.6 cr drivers and may give some support to garage claims as lets face it, the cars are the same. Just scroll down to the highly illuminating comments.

Hello raisbeck,

This is the exact article I've talked about before. The good news is that the new software in my car seems to stop it doing this. I haven't experienced this at all, even when trying to provoke it :-) It is a result of being in too high a gear, but as the car is geared higher than most, new drivers may well do this. Unfortunately, when it happens, it is very dangerous. Personally, I think VW, Skoda etc. have missed something here and should be using 6 speed boxes with more usual gear ratios. This would solve the surging problem and would also probably allow 6th gear to be higher than 5th gear currently and therefore help mpg. There doesn't seem to be a lack of power from the engine, so the higher ratio shouldn't be a problem.

Thanks,

Mike

Thanks for posting this interesting Auto Express thread. I have a 1.6 CD TDI 105 with 1800 miles on, always run on Shell Regular Diesel, and an overall average mpg of 47, plus the surging problem. Consumption seems to vary with no pattern. Best I have seen has been a slow B road trip of 12 miles with 62mpg, but a gentle mixed cross country trip this week gave just under 50mpg. Hard to get even 45 on a round 10 mile trip into the local small town. I keep hoping things are going to improve, but having read this thread it seems that this is a more general problem. I've not visited the dealer yet.

It would be interesting to get more reports, especially from people who are not having any problems, so please post if you have a 1.6 CD TD! I previously had a Fabia 1.9TDI, bought new, which regularly did 52mpg at an indicated 80mph on the motorway from day 1. My 2.0D Jaguar X Type is just back from a brisk 1100 mile trip to France with 4 up and luggage where it averaged 46.8mpg!

Hello tlx,

Interesting experiences. The surging problem should be solved by the latest software as installed in my car and I haven't experienced it since. However, it is ultimately caused by being in too high a gear, although the car seems to have higher ratio gears than most which means switching to and from it is problematic. Having said that, in my view the software should allow the engine to stall rather than rev the engine and cause acceleration without any request from the driver.

If you look on other forums, VW group cars using these engines are getting a lot of bad press. Poor economy, DPF issues, surging etc. are some of the commonly mentioned issues. Personally, I believe the DPF is causing a lot of issues and is definately a step too far on behalf of the ecomentalists. My other car is a Ford Galaxy (thank god without a DPF). My wife uses it around town only and we have a diesel simply because it is so much better when doing long trips and when seriously loaded. A petrol MPV (unless a big petrol) is really not good due to a lack of low down torque. However, if it did have a DPF, my wife would regularly have to take it on long runs down the dual carriageway to clear the DPF. What is the point of that!! In future, my wifes car will have to be a petrol as the DPF around town is simply not viable. Stupid piece of kit that and I hope they stop using them or make them work at low temperatures soon.

Thanks,

Mike

OK, so if all manufacturers tests are carried out in exactly the same manner, please tell me how I was able to achieve 64 mpg in my 08 Fiesta 1.6 TDCi for which Ford quote 64.?mpg yet when SEAT quote 65.7 I cannot get anywhere near that figure?

I now have a car with more modern technology but is not able to achieve the figures quoted

If it is a case of VW group engines bedding in, are we to assume VW/Skoda/SEAT only test a vehicle with in excess of 200,000 miles on the engine?

Is it a case that DPF regeneration uses so much fuel the consumption drops dramatically? Whilst I have not yet had a DPF light on my 6,500 miles car it has done 12 regens that I'm aware of!!

I'm beginning to think that as soon as the car is out of warranty, the DPF will be getting junked and a chip mod to disable the DPF regens!

My car is a 2011 MY Ibiza Sport CR 1.6 TDi, don't know what version of software the engine is running on.

Hi I am starting to wonder if this purchase is a good thing,I may stop the purchase of my 1.6cr tdi fabia,this engine does not make me feel very good the write ups are terrible I have not had the build date yet,is there anyone out there happy with their purchase of the cr 1.6 engined fabia,its a lot of money for a crap engine,thinking maybe a bmw 1 series instead,all I can see on the vw engine is a lot of negatives what should we do

Hello seboni121,

Well, what can I say!! Personally, I have to admit I wouldn't buy another. Maybe I'll go to another manufacturer/car and get exactly the same, but at the moment, it is a huge letdown for me. I'm seriously below the mpg I believe I should be able to expect and Skoda seem to be shrugging their shoulders. The garages simply say they can't change anything as the software does everything!! No tinkering like days of old. I was looking for 65mpg (still below the combined value) and I'm getting 52mpg (last tank) at 2500 miles. Even if it eventually gets to 65mpg, it will have cost me a lot in fuel on the way and fuel prices are only going one way. Previously, I had a Toyota Yaris and that was great from day one. 60-65mpg consistent and I had it for 6 years without a single problem that wasn't covered by warranty. Just servicing and that was it. Maybe I was lucky....who knows. As with all car purchases, it's a huge gamble, but VW do seem to be getting an awful lot of bad press at the moment. Their reliability rating is really beginning to take a fall as well.

Thanks,

Mike

OK, so if all manufacturers tests are carried out in exactly the same manner, please tell me how I was able to achieve 64 mpg in my 08 Fiesta 1.6 TDCi for which Ford quote 64.?mpg yet when SEAT quote 65.7 I cannot get anywhere near that figure?

I now have a car with more modern technology but is not able to achieve the figures quoted

If it is a case of VW group engines bedding in, are we to assume VW/Skoda/SEAT only test a vehicle with in excess of 200,000 miles on the engine?

Is it a case that DPF regeneration uses so much fuel the consumption drops dramatically? Whilst I have not yet had a DPF light on my 6,500 miles car it has done 12 regens that I'm aware of!!

I'm beginning to think that as soon as the car is out of warranty, the DPF will be getting junked and a chip mod to disable the DPF regens!

My car is a 2011 MY Ibiza Sport CR 1.6 TDi, don't know what version of software the engine is running on.

Hello TSIDSG?,

This is one of the things that confuses me. Why do some cars do it from scratch, yet others claim to need tens of thousands of miles on the clock. I suspect that Skoda may have tuned these cars too much to the fuel consumption test, which means they do poorly in reality, whereas others have probably tuned more to everyday life and therefore are slightly worse in the mpg tests. As to the DPF. What a useless piece of technology!! It really defies belief that something to try and improve air quality can result in you having to make special trips!!

I should also add that to run in excess of 2000rpm to help the regen process, means driving at 70mph, this speed is NOT conducive to good fuel economy. I never had to do this in my Fiesta as it did not have a DPF but still had low co2 figures AND good fuel economy!!!

Edited 15 November, 201015 yr by TSIDSG?

I should also add that to run in excess of 2000rpm to help the regen process, means driving at 70mph, this speed is NOT conducive to good fuel economy. I never had to do this in my Fiesta as it did not have a DPF but still had low co2 figures AND good fuel economy!!!

Absolutely. I cannot see how a DPF helps in any meaningful way at all. Obviously, you could drive at less than 70mph to get the 2000rpm by using a lower gear, but anyway you look at it, you're taking a journey simply to clear the DPF and therefore belching a load more fumes and emissions into the atmosphere doing so, as well as wasting your money burning diesel. For me, it shouldn't really be an issue as I do 65ish miles a day and therefore the regen is part of my normal journey. Can't say I've seen reduced mpg on the journey during which the regen occurs, but subsequent journeys seen to go down for a while. Either way, any device that requires specific journeys for it to continue functioning properly is clearly useless. I can't believe the manufacturers actually want to fit these, so presumably it's the emissions legislation giving them no option. Another interesting device is the ERV for recycling some exhaust gas. Many of the employees at the engine design and testing company near me disable these as they are so unreliable. Yes, they increase MPG very slightly and give a cleaner exhaust, but in their eyes, all they hear is problems with them. Again, another piece of kit that seems to appear only for emission regulations.

Reading this thread brings back so many memories of my 57 Corsa 1.3tdi (the one with the world award winning engine [spits on floor...]).....

During 18000 miles that thing never gave anywhere near its mythical mpg, no matter what I did. Trip computer claimed 60mpg but brim to brim consistently stood at 48mpg max. I wellied it to try and break it in - no difference - I can drive like an ECO star - I've managed a real 70mpg in my 98 Seat Alhambra (all 2 tonnes of it) from Sheffield to Norwich on more than one occasion.....I was expecting 75+mpg from the Corsa

But back to the Corsa - the things that irritated the most was

1. Stalling (in quite a violent way) when pulling away. (sound familiar?)

2. Stuttering (engine missing) around 1200rpm - making parking in Sainsburys a nightmare.

3. A tendency to surge when braking as if someone had wellied the accelerator just as I approach the traffic lights. (sound familiar?)

Dealer was useless, they did eventually do a software upgrade which helped a little with problem 3 only..

Anyway back to the stalling - not just me - all the family complained - eventually it stalled (violently - a sudden stop as if it had back fired at a roundabout) and I got a bootful of another car run into me - £2000+ worth of damage to me alone. Thankfully my little grandkids in the back were unhurt. We no longer have that piece of **** (or will have any vauxhall/fiat engined again)

I think this is all down to small capacity CR diesel engines. There are some fundamental design issues

1. Firstly CR injectors are pilot operated - that means the solenoid/piezo actuator operates a tiny integrated secondary hydraulic(diesel) circuit, which in turn operates the main injection valve. This is the only way to control the injector with the speed required and not requiring a 6+ inch diameter solenoid. As someone who worked for many years with electro hydraulic systems I can tell you that generally speaking, pilot operated valves are bad news - especially small ones. The size of the pilot circuit is incredibly small - at the fringe of what is manufacturable and any contamination is certain death to their reliable or accurate/repeatable operation.

2. Another thing got me thinking about the CR high pressure pump/rail - at low engine speeds there is surely a limited amount of pressure/volume available - unlike PD/Rotary pumps that basically can supply a full stroke delivery regardless of engine speed. I'm inclined to think this is why CR diesels are so puny at low speeds and prone to stall. Obviously the ECU programmers are so nervous about the stall possibility that them to program such an obvious kludge to try and avoid it.

3. I think more or less the same ECU design (made by Bosch probably) is used by all manufacturers with basically the same firmware - tailored slightly (mapping etc) to suit a particular engine. Hence the similarity between the FIAT and VAG symptoms.

CR - invented* by Fiat - enough said.......

*dubious claim - certainly exaggerated.

Edited 15 November, 201015 yr by xman

Reading this thread brings back so many memories of my 57 Corsa 1.3tdi (the one with the world award winning engine [spits on floor...]).....

During 18000 miles that thing never gave anywhere near its mythical mpg, no matter what I did. Trip computer claimed 60mpg but brim to brim consistently stood at 48mpg max. I wellied it to try and break it in - no difference - I can drive like an ECO star - I've managed a real 70mpg in my 98 Seat Alhambra (all 2 tonnes of it) from Sheffield to Norwich on more than one occasion.....I was expecting 75+mpg from the Corsa

But back to the Corsa - the things that irritated the most was

1. Stalling (in quite a violent way) when pulling away. (sound familiar?)

2. Stuttering (engine missing) around 1200rpm - making parking in Sainsburys a nightmare.

3. A tendency to surge when braking as if someone had wellied the accelerator just as I approach the traffic lights. (sound familiar?)

Dealer was useless, they did eventually do a software upgrade which helped a little with problem 3 only..

Anyway back to the stalling - not just me - all the family complained - eventually it stalled (violently - a sudden stop as if it had back fired at a roundabout) and I got a bootful of another car run into me - £2000+ worth of damage to me alone. Thankfully my little grandkids in the back were unhurt. We no longer have that piece of **** (or will have any vauxhall/fiat engined again)

I think this is all down to small capacity CR diesel engines. There are some fundamental design issues

1. Firstly CR injectors are pilot operated - that means the solenoid/piezo actuator operates a tiny integrated secondary hydraulic(diesel) circuit, which in turn operates the main injection valve. This is the only way to control the injector with the speed required and not requiring a 6+ inch diameter solenoid. As someone who worked for many years with electro hydraulic systems I can tell you that generally speaking, pilot operated valves are bad news - especially small ones. The size of the pilot circuit is incredibly small - at the fringe of what is manufacturable and any contamination is certain death to their reliable or accurate/repeatable operation.

2. Another thing got me thinking about the CR high pressure pump/rail - at low engine speeds there is surely a limited amount of pressure/volume available - unlike PD/Rotary pumps that basically can supply a full stroke delivery regardless of engine speed. I'm inclined to think this is why CR diesels are so puny at low speeds and prone to stall. Obviously the ECU programmers are so nervous about the stall possibility that them to program such an obvious kludge to try and avoid it.

3. I think more or less the same ECU design (made by Bosch probably) is used by all manufacturers with basically the same firmware - tailored slightly (mapping etc) to suit a particular engine. Hence the similarity between the FIAT and VAG symptoms.

CR - invented* by Fiat - enough said.......

*dubious claim - certainly exaggerated.

Hello xman,

You don't sound bitter :-) You may well be right, I don't know enough about the internals of these engines. The only thing I know, is that I'm disappointed. The extra-urban test is a bit of a joke anyway as it spends only a very limited amount of time at 70mph, the rest is accelerating/decelerating at much lower speeds. Not sure what extra-urban driving they've been doing!! Problem with creating a standard is that it gives something official for car companies to hide behind. If they published a figure and it was consistently found wanting and no standard existed, there would be a case for misdescription or similar. However, as its a standard, they can just sit back and say tested to the standard, no liability.

Mike