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Mii poor mpg

Nov 16, 2019
6
1
I bought a brand new 1 Litre petrol Mii back in August. Got about 3000 miles on it now. After the initial run in period, the fuel consumption is shocking (the first 2000 miles seemed ok, at about 50-52 mpg average). At 70mph on a clear motorway, I'm struggling to get above 45 mpg (instant/live consumption reading). The average mpg per journey is about the same. This is surely not normal. Doesn't seem to matter what petrol I put in it (95 unleaded at whatever fuel station i can find).

Checked tyre pressure-all normal (36 psi front and 33 rear). Got no dash warnings either. Tyres have decent tread. Car only usually carries me and a work bag, so I doubt weight is a factor. AC is off. Seems unaffected by electric consumption (music, phone etc)-any ideas? Thanks :)
 

andycupra

status subject to change
what engine is this?
whats the official mpg figures for this car?

often a smaller engine that is sold as 'economical' is not really suited to motorways - although in this case i do not know what engine you have this is a 'city' car?
 

camelspyyder

2 SEAT-er
Jun 26, 2014
1,305
175
I have a turbo 1.0 SEAT and it's mpg is badly effected by any adverse condition. Headwinds gradients wet roads all cut the mpg. But so does winter. As temperatures drop your average mpg will too, especially if your commute is short. I had a seasonal variation of About 10-20, percent based on a 25 mile A & B road commute. A 5 mile commute would possibly see a seasonal mpg drop of 25-40 percent in winter.

Mine was thirsty for the first 2000 miles but then seemed to free up as it was run in, it was also going in to springtime so ambient temperature was in the up too.
 

G.P

Active Member
Sep 3, 2011
1,273
41
Worcestershire
Unfortunately from my experience smaller sized engines together with 3 cylinder engines unless driven at low speeds and very slow acceleration rarely return what we expect, a family member went from an Ibiza 1.4 cylinder none turbo retuned 40mpg to a 4 cylinder 1.2 tsi returning 38mpg and now has the new shape Ibiza so lighter but with the 1.0 3 cylinder engine returning 34 mpg.

I now never like to mention what my Leon returns..[B)]
 

andycupra

status subject to change
agreed, the current cyclic tests are terrible and not representative of the real world.
many smaller turbo engines are apparently going to give you better MPG but my experience and others i know find differently.
a larger N/A engine i find is better, the best car i ever had for MPG was a 2.9 v6.
 
Nov 16, 2019
6
1
what engine is this?
whats the official mpg figures for this car?

often a smaller engine that is sold as 'economical' is not really suited to motorways - although in this case i do not know what engine you have this is a 'city' car?

@andycupra thanks for the reply. My engine is 60hp, 1 litre petrol, non turbo, 3 cylinder. The official figures for the 60hp 1 litre engine are 55-59 city, 72-74 highway, 66 combined. I take these with a pinch of salt, but 45 combined is surely pushing it. MPG source here.

My old VW Up! (move up! edition, 1 litre, 60hp), which is essentially a rebadged version of the same car, managed 55-60 mpg easily.
I appreciate that smaller cars aren't suited to motorway driving but the issue appears to affect all roads and all speeds, with each speed drawing about 10-20% more fuel consumption than my old VW Up. Same for weather/road conditions. Perfect weather and smooth tarmac isn't making the car any more economical.
 
Nov 16, 2019
6
1
I have a turbo 1.0 SEAT and it's mpg is badly effected by any adverse condition. Headwinds gradients wet roads all cut the mpg. But so does winter. As temperatures drop your average mpg will too, especially if your commute is short. I had a seasonal variation of About 10-20, percent based on a 25 mile A & B road commute. A 5 mile commute would possibly see a seasonal mpg drop of 25-40 percent in winter.

Mine was thirsty for the first 2000 miles but then seemed to free up as it was run in, it was also going in to springtime so ambient temperature was in the up too.

Thanks-I appreciate it's colder now, although my old Up! wasn't nearly so harshly affected by temp (assuming that's the cause). Food for thought though.
 
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