Low-ish power and mpg
Discussion
Is your car fitted with a DPF? And if so, can VAG-COM tell you if a regeneration is taking place?
Regenerating the DPF has quite a negative effect on fuel economy, and depending on the vehicle, some people have been known to notice a dip in performance
It does sound more like either a cooling system or sensor related problem though, as heat soak seems to be the determining factor of both economy and power delivery
Regenerating the DPF has quite a negative effect on fuel economy, and depending on the vehicle, some people have been known to notice a dip in performance
It does sound more like either a cooling system or sensor related problem though, as heat soak seems to be the determining factor of both economy and power delivery
Relying on the cars average mpg readout is a fundamentally flawed way of judging actual mpg. The only way to gauge mpg accurately is to record amount of fuel used and miles travelled and work it out yourself, anything else is pure speculation.
Secondly, any engine must run a richer fuel mix when cold to help the combustion process. Therefore getting a better average mpg readout after restarting the car when warm (even after a 10 min break) is entirely normal. I also very much doubt your car is having any problems if you have worked out the average as 57mpg, even a small misfire or running problem would have a much bigger affect on mpg.
I'm also not surprised you find performance sluggish as you "change up at 2500rpm". Try changing gear at 3000rpm at least if you need any kind of performance. Dropping down to 1500rpm in a small capacity turbo engine is always going to result in substantial lag before the turbo gets spinning again.
Secondly, any engine must run a richer fuel mix when cold to help the combustion process. Therefore getting a better average mpg readout after restarting the car when warm (even after a 10 min break) is entirely normal. I also very much doubt your car is having any problems if you have worked out the average as 57mpg, even a small misfire or running problem would have a much bigger affect on mpg.
I'm also not surprised you find performance sluggish as you "change up at 2500rpm". Try changing gear at 3000rpm at least if you need any kind of performance. Dropping down to 1500rpm in a small capacity turbo engine is always going to result in substantial lag before the turbo gets spinning again.
I believe the thermostat is around £20 from SEAT, but as stated above, I can't touch anything, the car is under warranty.
As for the DPF, yes I have one, but I drive mainly motorway miles, about 80% of 600 miles a week is motorway miles. Also this problem happens every time, regardless of how long the journey is, it is miles better after a restart.
As for the motorway test, as McSam said, all of the testing was done within the same hour, on the same stretch of the M58, and all the averages were taken over both directions, as obviously, one way can be downhill, the other uphill. When joining the motorway, I got up to a constant 70mph before leaving the slip road, and stuck the cruise control on to maintain consistency. I reset the trip computer as I crossed the slip road line, and took my reading as I left the motorway and crossed the slip road line again. I did the same coming back up the other side of the motorway.
On the 'warm-start' test, I did the same procedure as above, and the mpg was around 12-13mpg better. It's also incredibly noticeable around town. Starting cold and bringing up to temperature around town, is around 48mpg, but it's near 55-60mpg when starting with a warm engine.
As for the two people saying that the trip computer is counting the cold start period, and fuel running richer when cold, when the engine reaches temperature I restart the trip computer, all of my measurements have been done with a warm engine, as I understand a diesel engine isn't efficient until warm. No measurements have been done unless the engine is completely up to temperature, so this means that no cold engine driving is included.
With regards to the power issue, I understand there isn't going to much power and performance when shifting and dropping to 1,500 RPM, that was never my problem. My problem is that the car drives differently at those same RPM when the car is started warm, than when it is fully up to temperature after being cold. I don't think the car is sluggish in general, but I do think the power is different between the two scenarios.
@ Olivera - As stated before, the trip computer is accurate within 2mpg over a tankful. I don't get the chance to do a long enough motorway stint, get somewhere, not stop the engine and go back up the other way, and then do the same procedure again (but stopping the engine) so I can get an accurate hand calculation. If I do get the chance, I'll definitely do it, because it's more proof, but I find it hard that a trip computer that is accurate to 2mpg over a tankful, is 12mpg out on two motorway runs that are identical, or two town runs. The pattern is also consisetent, as I've noticed it over the past couple of months, every day. I've not just noticed it willy nilly, it's been happening pretty much since I had the car.
I am doing my best to explain my situation.
As for the DPF, yes I have one, but I drive mainly motorway miles, about 80% of 600 miles a week is motorway miles. Also this problem happens every time, regardless of how long the journey is, it is miles better after a restart.
As for the motorway test, as McSam said, all of the testing was done within the same hour, on the same stretch of the M58, and all the averages were taken over both directions, as obviously, one way can be downhill, the other uphill. When joining the motorway, I got up to a constant 70mph before leaving the slip road, and stuck the cruise control on to maintain consistency. I reset the trip computer as I crossed the slip road line, and took my reading as I left the motorway and crossed the slip road line again. I did the same coming back up the other side of the motorway.
On the 'warm-start' test, I did the same procedure as above, and the mpg was around 12-13mpg better. It's also incredibly noticeable around town. Starting cold and bringing up to temperature around town, is around 48mpg, but it's near 55-60mpg when starting with a warm engine.
As for the two people saying that the trip computer is counting the cold start period, and fuel running richer when cold, when the engine reaches temperature I restart the trip computer, all of my measurements have been done with a warm engine, as I understand a diesel engine isn't efficient until warm. No measurements have been done unless the engine is completely up to temperature, so this means that no cold engine driving is included.
With regards to the power issue, I understand there isn't going to much power and performance when shifting and dropping to 1,500 RPM, that was never my problem. My problem is that the car drives differently at those same RPM when the car is started warm, than when it is fully up to temperature after being cold. I don't think the car is sluggish in general, but I do think the power is different between the two scenarios.
@ Olivera - As stated before, the trip computer is accurate within 2mpg over a tankful. I don't get the chance to do a long enough motorway stint, get somewhere, not stop the engine and go back up the other way, and then do the same procedure again (but stopping the engine) so I can get an accurate hand calculation. If I do get the chance, I'll definitely do it, because it's more proof, but I find it hard that a trip computer that is accurate to 2mpg over a tankful, is 12mpg out on two motorway runs that are identical, or two town runs. The pattern is also consisetent, as I've noticed it over the past couple of months, every day. I've not just noticed it willy nilly, it's been happening pretty much since I had the car.
I am doing my best to explain my situation.
Edited by xreyuk on Thursday 14th June 20:46
morgrp said:
When it's playing up will it accelerate much past 70-80mph? (Serious question) - they do have a problem with the variable veins on the turbos and it can trick the ecu into going into "get you home" mode
Get you home mode is usually very very noticeable though. About 50, or even 30% of power in my - very limited - experience of them.As far as the OPs problem, it certainly sounds like a sensor sticking or giving a false reading. Thermostat would be the first place to start, although there could be something electronic further up the system as well. Im not sure why it would change once you've been sat, it sounds to me like resetting the ECU is the solution. Seat might reprogram the ECU for you, just do a wipe and clean install of the software which. Im not familiar with VAG COM, but it should be possible to see sensor readings, so try and pull up the thermostat reading and see. It might only be binary - ie hot or cold - but from there you can work out if that is the problem or if the ECU is for some reason 'sticking' on a cold setting.
Thanks, I'll make a log of the coolant temperature and anything else I think is relevant on next start up and see what happens.
I was thinking thermostat myself, but like I said, it doesn't appear to be a long warm up period. Hopefully they won't have to reset the ECU, but we'll see.
Any other recommendations would be greatly appreciated.
I was thinking thermostat myself, but like I said, it doesn't appear to be a long warm up period. Hopefully they won't have to reset the ECU, but we'll see.
Any other recommendations would be greatly appreciated.
Edited by xreyuk on Thursday 14th June 23:01
xreyuk said:
Locke said:
I Can't see a faulty thermostat being the cause myself.
What can you see being the cause?I'm not a mechanic but a thermostat malfunctioning on a car that age is quite rare, It wouldn't effect the power like you describe and although it would effect mpg I can't see it resulting in a 12mpg difference.
HTH.
Locke said:
Sorry, I should maybe expand.
I'm not a mechanic but a thermostat malfunctioning on a car that age is quite rare, It wouldn't effect the power like you describe and although it would effect mpg I can't see it resulting in a 12mpg difference.
HTH.
Cheers, oh well, here's to hoping.I'm not a mechanic but a thermostat malfunctioning on a car that age is quite rare, It wouldn't effect the power like you describe and although it would effect mpg I can't see it resulting in a 12mpg difference.
HTH.
Any idea what else it could be? It has been suggested it could be the MAF, but I wouldn't have thought it was have affected it in this way.
Well, as usual.
Sods law kicked in today, and for the first time since I've owned the car, it behaved properly as soon as it got warm, from a cold start. It's never done this before, and it would happen when I went to log the information. I'll try doing another log over the next few days to get one of the bad startups. Hopefully though, that might have been the last I saw of it today.
Quick question, what temperatures should I be seeing? I saw the following:
Coolant Temp at Radiator outlet: 44deg
Coolant Temp: Went as high as 97deg, and then cooled a little to 93deg.
Oil Temp: Settled at around 89/90 deg.
That coolant temp seems a little bit high from what I've read on the internet?
Sods law kicked in today, and for the first time since I've owned the car, it behaved properly as soon as it got warm, from a cold start. It's never done this before, and it would happen when I went to log the information. I'll try doing another log over the next few days to get one of the bad startups. Hopefully though, that might have been the last I saw of it today.
Quick question, what temperatures should I be seeing? I saw the following:
Coolant Temp at Radiator outlet: 44deg
Coolant Temp: Went as high as 97deg, and then cooled a little to 93deg.
Oil Temp: Settled at around 89/90 deg.
That coolant temp seems a little bit high from what I've read on the internet?
McSam said:
Sounds reasonable to me. The thermostat probably opens around 88-90'C and it won't go much above that, but a peak of 97 and settling to 93 isn't anything to worry about, unless these engines are known for running very cold?
Here's hoping that's the end of it!
Hopefully so. I'm secretly hoping it's just decided to behave itself, it was even much better at high speed after a while, just after it had warmed up, it was poor though.Here's hoping that's the end of it!
However, I'll keep monitoring it, and if needs be over the next few days, do another test and possibly post on here.
xreyuk said:
Since I bought my Seat Leon 1.6TDI CR, I have been having varying fuel consumption results. I was told to adapt my driving style, and that has certain helped, however, I definitely think there is a problem with the car.
The problem I've noticed, is if I start the engine from cold, and let it get up to temperature, it NEVER reaches full efficiency, and it feels like an engine with 80BHP instead of 105BHP.
If I then stop for around 10-15 minutes, and turn the engine back on (whilst it's still warm), the MPG takes a massive jump up, especially on the live data display. The power also feels like it should. This is how I would have thought the car would perform all of the time.
I decided to do a test. I started the engine cold, got it up to temperature and went to the motorway nearby. I reset the trip when I reached 70mph, and stuck cruise control on. I did a 10 mile journey to the end of the motorway, made a note of the reading, and then did the exact same thing back up the other side (waiting until 70mph to reset the trip etc). I averaged the two readings. at 52.9mpg.
I then stopped the engine for 20 minutes, got a cup of tea etc. I then did the exact same test on the exact same bit of motorway. The average mpg this time around was 65.4mpg. A MASSIVE jump.
It's also returning on average 10mpg higher in urban driving when started warm, as opposed to being brought up to temperature and the trip reset
Do you have any idea what could be causing this? Someone on another forum said they noticed similar symptoms in a Mondeo with a faulty temperature sensor/thermostat. I've also read that it could be the MAF.
I have fully activated VAG COM, so if anyone could suggest anything I could be maybe monitor to take to SEAT, because, as usual, I'm just getting the old 'we're not having an issue when we drive it'. The car is under warranty so without an error code or some sort of evidence I don't know how far I'll get.
Thanks guys
Sounds completely normal TBH & not sure why there might seem to be an issue.The problem I've noticed, is if I start the engine from cold, and let it get up to temperature, it NEVER reaches full efficiency, and it feels like an engine with 80BHP instead of 105BHP.
If I then stop for around 10-15 minutes, and turn the engine back on (whilst it's still warm), the MPG takes a massive jump up, especially on the live data display. The power also feels like it should. This is how I would have thought the car would perform all of the time.
I decided to do a test. I started the engine cold, got it up to temperature and went to the motorway nearby. I reset the trip when I reached 70mph, and stuck cruise control on. I did a 10 mile journey to the end of the motorway, made a note of the reading, and then did the exact same thing back up the other side (waiting until 70mph to reset the trip etc). I averaged the two readings. at 52.9mpg.
I then stopped the engine for 20 minutes, got a cup of tea etc. I then did the exact same test on the exact same bit of motorway. The average mpg this time around was 65.4mpg. A MASSIVE jump.
It's also returning on average 10mpg higher in urban driving when started warm, as opposed to being brought up to temperature and the trip reset
Do you have any idea what could be causing this? Someone on another forum said they noticed similar symptoms in a Mondeo with a faulty temperature sensor/thermostat. I've also read that it could be the MAF.
I have fully activated VAG COM, so if anyone could suggest anything I could be maybe monitor to take to SEAT, because, as usual, I'm just getting the old 'we're not having an issue when we drive it'. The car is under warranty so without an error code or some sort of evidence I don't know how far I'll get.
Thanks guys
Car performs less than wonderfully when warming up shocka (just like anything does when going from a less than ideal state to trying to get to that theoretical ideal state) & gets appreciably better when closer to that ideal.
Engines take longer to get fully warmed than many people expect or realise & current engines when cold seem to be far more sensitive to this, from both a power and economy perspective - I know my heap feels much better after 20+ miles.
As a related aside, I had a hire car for @ 3 months with the same engine & power wise it felt permanently miserable - closer to 10.5bhp than 105 - and also was a country mile short of claimed economy. My driving style is good and I couldn't persuade it to get above 50, let alone the claimed 72.6 (ish
).OP -- Do a 100+ mile run from cold and then the same when warm. The latter will inevitably be better, but if still easily well above 10mpg worse, you might just have some cause for concern. 10 miles or so cold - warm Vs 10 miles warm on a steady m-way run will tell you rock all.
xreyuk said:
I decided to do a test. I started the engine cold, got it up to temperature and went to the motorway nearby. I reset the trip when I reached 70mph, and stuck cruise control on. I did a 10 mile journey to the end of the motorway, made a note of the reading, and then did the exact same thing back up the other side (waiting until 70mph to reset the trip etc). I averaged the two readings. at 52.9mpg.
I then stopped the engine for 20 minutes, got a cup of tea etc. I then did the exact same test on the exact same bit of motorway. The average mpg this time around was 65.4mpg. A MASSIVE jump.
I then stopped the engine for 20 minutes, got a cup of tea etc. I then did the exact same test on the exact same bit of motorway. The average mpg this time around was 65.4mpg. A MASSIVE jump.
The car probably started off a little cooler on the second test, which only contributes to the clear disparity in the results.
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