Could cold fuel cause bad MPG?

[Ben]

I have only managed to get just over 400 miles out of the last couple of tanks. I usually get 500.
In the summer I put an inline filter in, to rule out air getting into the standard fuel filter housing.
Now I am wondering whether due to the drop in temperature over the last couple of weeks, the fuel is below an efficient temperature?

Could this be the cause of such bad MPG? I would have thought once the engine was warm the fuel would get heated when in the pump, but maybe the standard filter housing is still required?

Thanks for any input, Ben

[Piggy]

The cold in general can drop mpgs as it takes longer for the engine to get to optimum efficiency temp.

But shouldnt cause that much difference.

You runnung veg? How many miles done on inline filter and what type you use?

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In fact, 500miles isnt really that good either. 60litre tank you should 550minimum

[Daniel306]

I never see more that 420 ish out of my 306

[Martin306]

It's a 60 litre tank isnt it? 13.2 gallons. say you use 12 gallon before the light.

500 miles to a tank is still "bad". That's only like, 42mpg lol

400 is proper bad, works out to 34mpg.

Standard filter housing does heat the fuel, cold fuel would be harder to burn I would have thought. I don't see how it would make much difference, but clearly it does. :O

[Daniel306]

My 307 averages 32.8, but its the 16v hdi

[welshpug]

damn, that's rather poor, should be rather more than that easily, but depends very much on driving style and traffic conditions.

[Daniel306]

I drive mostly B roads, nearest motorway its 150 miles away, and the next best thing is the A9

[Martin306]

I drive mostly B roads, nearest motorway its 150 miles away, and the next best thing is the A9

The A9, can't even hold 60 there for long before you're right up the arse of a lorry or some old dodderer driving at 40. When you get to the North, it's all hills. The worst road for eco driving lol

I'd rather drive the old road up over Glenshee and Braemar. If I'm gonna burn fuel, might as well have fun.

[Daniel306]

That the way i see it, where abouts are you from?

[Ben]

The cold in general can drop mpgs as it takes longer for the engine to get to optimum efficiency temp.

But shouldnt cause that much difference.

You runnung veg? How many miles done on inline filter and what type you use?

---

In fact, 500miles isnt really that good either. 60litre tank you should 550minimum

No I just run straight diesel, can't be bothered to faff around with veg anymore. The inline filter has done less than 5k, and its a large Audi one, can't remember what model its for.

I've only ever got more than 500 miles on a couple of occasions, and that's in the last 4 years!

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It's a 60 litre tank isnt it? 13.2 gallons. say you use 12 gallon before the light.

500 miles to a tank is still "bad". That's only like, 42mpg lol

400 is proper bad, works out to 34mpg.

Standard filter housing does heat the fuel, cold fuel would be harder to burn I would have thought. I don't see how it would make much difference, but clearly it does. :O

I know most people say they get ~50mpg, but I've never really considered 42mpg to be bad, as that is what peugeot said the cars would do.

[Martin306]

Well, let me put it this way.

Peugeot SAY my 106 1.5D only does 45mpg.

I absolutely hammer the f*ck out of it, and get 51mpg. Changing up at 4000rpm.

[Dum-Dum]

My economy has dropped as well in the last couple of months but I doubt its due to cold fuel

[Piggy]

I put fuel in mine the other week...50/50 mix of veg n derv.
Just over half a tank...
Light hasnt come on yet and I am on 320miles...
Im not near any nice open roads really either

[Tom]

I put fuel in mine the other week...50/50 mix of veg n derv.
Just over half a tank...
Light hasnt come on yet and I am on 320miles...
Im not near any nice open roads really either

You've got a different engine to the rest of us and a quick spooling turbo, yours should be way better than what we can do.

[Martin306]

I put fuel in mine the other week...50/50 mix of veg n derv.
Just over half a tank...
Light hasnt come on yet and I am on 320miles...
Im not near any nice open roads really either

You've got a different engine to the rest of us and a quick spooling turbo, yours should be way better than what we can do.

Piggy muse be a shit driver imo.

[Tom]

Well when i spoke to Zakk about the 2.1 dumdum put together he said it was heroic on fuel! And if Piggys got that quick spooler his should be better still.

[Piggy]

Have you seen my videos?? Im not an eco warrier

[londondan86]

Cold fuel shouldn't make much of a difference as the pump will heat it to an extent when the engine is up to temp anyway. As said cold weather will make a big impact but not that bad!!

Check your brakes aren't binding on any corner

[Piggy]

Good call really.
Fuel filter
Brakes free (inc handbrake...can be big impact)
Tyre pressures
Not using AC a lot??
Loadsa crap in the boot?

Maybe lose some weigh yaself?

[Ben]

Good call really.
Fuel filter
Brakes free (inc handbrake...can be big impact)
Tyre pressures
Not using AC a lot??
Loadsa crap in the boot?

Maybe lose some weigh yaself?

Yeah good call on the brakes, I checked the rears a couple of weeks ago but haven't got round to doing fronts yet.
Fuel filter hasn't done many miles but I'll replace with new standard filter to rule it out.
I put 35psi in all tyres a few weeks ago but I'll check them to see if they are going down (pretty sure they're not though).
I don't have AC.
Nothing in the boot.

Unfortunately at under 10st I haven't really got any weight to lose!

[Tom]

Some peoples XUD's seem really good on fuel and then others are just wank :/

[Toms306]

Some peoples XUD's seem really good on fuel and then others are just wank :/

They should swap then....see if its the driver/conditions or if its the engine at fault lol.

Must admit, my economy has been terrible lately, averaging under 45mpg in the cold weather! Its just because the engine takes so long to warm up atm though I think.

[Tom]

That reminds me i need to go put the rest of my crisp and dry in the car

[THE_Liam]

I reckon veg will affect MPG when it's cold as it takes more power for the engine to spin the pump when it's full of thick veg, but I doubt it'd make a noticeable difference. I only get 450 miles to a tank but that's all round town which isn't bad, on a run to Cornwall and back it's more like 550 which isn't amazing by todays standards but for an old-tech IDI with a rotary pump, no ECU, no dynamic advance and 110k, 50mpg on pure veg is pretty good...