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Model specific boards => Golf mk4 => Golf mk4 TDI => Topic started by: josh_419 on 20 November 2010, 17:52
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I have been getting around 5mpg less on my same trip to work every day now its getting colder.
Diesel being a heat engine and taking in cold air reducing mpg at all ?
Its a rumor, correct me!
And no, i dont have a pair of different shoes (heavier ones..)
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Cold Mornings make it work harder. Simples. :smiley:
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yes it is a sad state of affairs! :cry:
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Mine don't really change much to be honest, maybe cuz mine is sh*t all year round :grin:
Dunno why i'm :grin: as most of the time it's got me :cry:
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suffering the same unfortunately, especially early mornings
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Once it has fully warmed up mine hasn't changed.
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i drive a gt tdi and also have been feelin like my mpg has dropped. but i think it is those shorter journeys, especially when the car doesnt get channce to warm up.
i looked in the vw manual in the glove box and it says that your fuel consumption is double until the cat is up to temperature and it takes approximately 4 km of driving to warm it up.
perhaps its just taking longer to get the temperature in the cat. since reading that i never accelerate hard until i can see the water temp gauge start to move. and it doesnt budge for longer during these cold morning we have been getting.
take alook in your manula, im sure you'll read the same. look under mpg or emissions.
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i drive a gt tdi and also have been feelin like my mpg has dropped. but i think it is those shorter journeys, especially when the car doesnt get channce to warm up.
i looked in the vw manual in the glove box and it says that your fuel consumption is double until the cat is up to temperature and it takes approximately 4 km of driving to warm it up.
perhaps its just taking longer to get the temperature in the cat. since reading that i never accelerate hard until i can see the water temp gauge start to move. and it doesnt budge for longer during these cold morning we have been getting.
take alook in your manula, im sure you'll read the same. look under mpg or emissions.
So what happens if you have a de-cat. I don't; im jut wondering if that changes your MPG?
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i drive a gt tdi and also have been feelin like my mpg has dropped. but i think it is those shorter journeys, especially when the car doesnt get channce to warm up.
i looked in the vw manual in the glove box and it says that your fuel consumption is double until the cat is up to temperature and it takes approximately 4 km of driving to warm it up.
perhaps its just taking longer to get the temperature in the cat. since reading that i never accelerate hard until i can see the water temp gauge start to move. and it doesnt budge for longer during these cold morning we have been getting.
take alook in your manula, im sure you'll read the same. look under mpg or emissions.
So what happens if you have a de-cat. I don't; im jut wondering if that changes your MPG?
I'm 90% I witnessed better MPG after a de cat.
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Supposed to b one of the benefits of a de-cat, better flow so better power = better fuel economy depending on your driving style.
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I have defanatly noticed better mpg since fitting my miltek decat, im still getting around 50mpg at the mo with the cold weather.
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I managed to get 57MPG on Saturday, tempature was between -3 and -7 all day :cool:
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You guys reckon it's mainly low MPG when the car is cold at the start of the journey then ok after that?
What I mean is you start it in the morning and the enging is stone cold i'd class that as a cold start and MPG would most probably start off really bad then gradually get better, but on a 2nd journey if the car was started from semi cold engine as in not stone cold you reckon you should get better MPG on the 2nd journey?
Just wanted to see what you guys reckon.
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Yes will be pretty poor mpg for a while, but as soon as engine has some heat in it, it should go up quickly.
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Hi, sorry to crash thread, but when you say low mpg, how low are you taking about on trip computer?
reason i ask is i have 130 model and my trip rarely shows more than 42mpg average on a 30 mile motorway/a road journey to work. ive replaced maf thinking it was that but its no better.
any thoughts?
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i have noticed that when i start the car first thing in the morning there is a lot of blue smoke this has only just started since its been very cold.
not sure what its burning but seems ok after a minute on tick over, has anyone else had this problem ?
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mine smokes like f**k in this weather.
I do a 50 mile commute and getting around 45-48mpg sat at 70-75mph.
Get it scanned with vag-com for any fault codes
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Our Polo has dropped almost 50miles from it's usual MPG so far. Cold weather is cack for diesels on start up.
Blue smoke indicates oil.... how blue are you talking?
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the blue smoke is only on start up its not to bad as once its running there is no smoke.
could it just be unburnt fuel?
the car is due a service in about 2k miles and its on a 2 year or 20k service times could it just be the fact it needs the service.
had the car looked at on the vagcom 2 months ago no problems then.
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A colder engine will give poor mpg whilst it is heating up.
I've always found I get better performance in winter (perhaps its denser fuel/air than summer), but as a result, I almost always loose about 7 mpg.
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Petrol and Diesel operation are two completely different beasts in the cold though ben, so our diesels will lose a lot more if only doing short runs in this type of temperature.
Postie - It sounds like you are just getting a little oil past the rings when it is this cold. The material will contract a lot more than usual so when the engine first starts and begin to get warm there is a larger clearance past the rings than there should be. Once up to temp and the materials are warmer they will expand that little bit and close up the clearances. Nowt to worry about.
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thanks for that Agreeable Slick,
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Oh p.s. I should mention, just keep an eye on your oil level, it will probably need topping up what with the cold temperatures dragging on so much.
If you do drive it from cold, let it get to temp before sitting on the turbo as that will definately not help. :smiley:
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thanks.
i have been looking at the temp but since the cold weather started it does not get to 90 until ive done about 10 miles of just very careful and slow driving it was fine before the cold only took a mile or two to reach 90 on temp.
since the cold weather started i have just let the car sit there running to de-ice the windows which means its running for about 5mins some mornings, now i have said that some one is going to say i should not let it sit there on tick over for so long as its not good for some thing on the car.
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Well, running an engine when it's sub zero material temperature is not good for the engine, but what are you going to do? :laugh: - only thing you could do is put it in a heated garage overnight or wrap he engine in a heat blanket, and lets be honest that's not going to happen is it.
Like I mention, try to keep it off the turbo as much as possible, as that will help the engine cope without the sudden ramp up of speed when the turbo kicks in.
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Agreeable slick you are one knowledgeable (SP) fooker mate :)
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My 1.9 gt tdi 130 dropped from 69.1 to 64.4 after the cold weather set in and fitting bigger/wider alloys :cry:
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My 1.9 gt tdi 130 dropped from 69.1 to 64.4 after the cold weather set in and fitting bigger/wider alloys :cry:
Cheeky fooker i'd love to get that kinda MPG i've never seen that owning the car for over a year :(
What kind of driving do you do to achive that?
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Driving 60mph on the motorway using an asda lorry to set the pace :grin:
Mine can easily acheive it, just feather the accelerator when needed but as soon as you hit traffic thats it :(
City driving i get about 38-40 over a month due to sitting in gridlock traffic with constant stop starting!
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i looked in the vw manual in the glove box and it says that your fuel consumption is double until the cat is up to temperature and it takes approximately 4 km of driving to warm it up.
perhaps its just taking longer to get the temperature in the cat. since reading that i never accelerate hard until i can see the water temp gauge start to move. and it doesnt budge for longer during these cold morning we have been getting.
That doesn't make sense, why would the CAT have any effect on fuel economy? It would obviously have a massive difference on emissions but I can't see what the CAT would have to do with fueling?
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i looked in the vw manual in the glove box and it says that your fuel consumption is double until the cat is up to temperature and it takes approximately 4 km of driving to warm it up.
perhaps its just taking longer to get the temperature in the cat. since reading that i never accelerate hard until i can see the water temp gauge start to move. and it doesnt budge for longer during these cold morning we have been getting.
That doesn't make sense, why would the CAT have any effect on fuel economy? It would obviously have a massive difference on emissions but I can't see what the CAT would have to do with fueling?
Fuel can be used to help the light off process in the cat, and prevent too much damage to it. I.E. there is sometimes an injection of fuel on the exhaust stroke hence the increased use of fuel until it's up to temp.
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i looked in the vw manual in the glove box and it says that your fuel consumption is double until the cat is up to temperature and it takes approximately 4 km of driving to warm it up.
perhaps its just taking longer to get the temperature in the cat. since reading that i never accelerate hard until i can see the water temp gauge start to move. and it doesnt budge for longer during these cold morning we have been getting.
That doesn't make sense, why would the CAT have any effect on fuel economy? It would obviously have a massive difference on emissions but I can't see what the CAT would have to do with fueling?
Fuel can be used to help the light off process in the cat, and prevent too much damage to it. I.E. there is sometimes an injection of fuel on the exhaust stroke hence the increased use of fuel until it's up to temp.
Unburnt fuel in a CAT is bad news for its health as you say, so running richer is not desirable - richer when cold yes, richer for the health of the CAT when cold - doesn't sound right to me.
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Sorry I worded that badly it's like this.
Running rich = higher/hotter exhaust temps, an late post injection of fuel into the exhaust cools exhaust temps, which helps cool the gases entering both the turbo and cat. This prevents temperature fatigue cracks in both the metals of the turbo and the materials in the cat until they are up to a reasonably temp in which case the post injection map tends to switch over.
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Sorry I worded that badly it's like this.
Running rich = higher/hotter exhaust temps, an late post injection of fuel into the exhaust cools exhaust temps, which helps cool the gases entering both the turbo and cat. This prevents temperature fatigue cracks in both the metals of the turbo and the materials in the cat until they are up to a reasonably temp in which case the post injection map tends to switch over.
I always thought running richer gave lower/cooler exhaust temps and leaner gave higher/hotter exhaust temps, infact some high perfomance engines run rich specifically to cool?
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Remember we are talking about initial start up and complete combustion. Sticking unburnt and non combusted fuel in to the cylinder will lower burning temps.