Author Topic: Extremely poor MPG  (Read 1047 times)

Offline Pudding

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Re: Extremely poor MPG
« Reply #15 on: November 15, 2019, 04:34:42 PM »
No petrol engine is efficient on short journeys, especially over winter.   The amount of fuel chucked in for cold starting and during warm up is unreal.  The injectors actually fire twice for a certain time frame to heat the cats up.  All that lovely moolar poured down the drain  :grin:

Cause and effect - the longer it takes for an engine to warm up, the more fuel it will use.   The best way to treat a petrol engine is to get on it, hard, as soon as possible.  Get some heat and air into it asap.

Unfortunately such driving conditions is also hard on the engine oil, so that will need changing more regularly as well if the engine rarely gets thoroughly heated through.
Black Edition 30 with manually selected cogs, a beefier clutch, some extra boost and them Whiteline thingies, otherwise standard.

Offline Deangti07

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Re: Extremely poor MPG
« Reply #16 on: November 21, 2019, 11:10:07 AM »
I don’t think 15mpg is normal for these car I think i have a serious fuel problem my friends m4 does the same mpg as mine Any ideas of what could be wrong ?

Offline bobby_fodge

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Re: Extremely poor MPG
« Reply #17 on: November 21, 2019, 11:36:00 AM »
service it, oil & filter, fuel filter, plugs, if not done recently.

What fuel are you using?

Have you scanned it to check for any fault codes?

Are any brakes binding?

Offline Pudding

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Re: Extremely poor MPG
« Reply #18 on: November 21, 2019, 12:44:42 PM »
As above, especially the brakes.  The rear calipers are notorious for seizing up. 

But as we've discussed, 15mpg around London and low 30s on a run is not abnormal.

You can't compare a 12 year old engine to a modern one with the latest EU emissions control, but it sounds like the M4 is equally poor at urban speeds which just cements what we've already said.  It's just how petrol engines are.  You can either suck it up or sell it and buy a Nissan Leaf.
Black Edition 30 with manually selected cogs, a beefier clutch, some extra boost and them Whiteline thingies, otherwise standard.

Offline snowball05

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Re: Extremely poor MPG
« Reply #19 on: November 21, 2019, 08:21:07 PM »
I get about 35mpg on my 25 mile run to work down the M3 @ 70mph. If I get caught in traffic and slow to 60mph it goes up to 37-38mpg. Stock Mk5, manual, 65000 miles.


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Offline OllieL

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Re: Extremely poor MPG
« Reply #20 on: November 26, 2019, 08:09:32 AM »
I get around 300-320 miles from a tank with my commute being a fairly stop/ start commute and an average of 30MPG.

I can often see low 30’s on the way to work (less traffic the times I leave), with mid 20’s on the way home.

I thought this was reasonable for a GTi of this age (130K BWA)

Ollie


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Offline Dan_FR

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Re: Extremely poor MPG
« Reply #21 on: November 26, 2019, 01:39:24 PM »
My tank average is usually 18MPG. Combination of short journeys, stop/start driving slowing to a crawl of speedbumps and a lead foot once it gets up to temps. Can still get 400+ miles all motorway

Not comparable as everyone's driving style and road conditions will be different.
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Offline E8RNX

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Re: Extremely poor MPG
« Reply #22 on: November 27, 2019, 11:57:29 AM »
I average 15 and under pretty much all the time. However on a run I can easily achieve amazing numbers.. other day constant flowing traffic, no heavy foot and got 28MPG over about 5 miles. Just depends on driving with these cars really, the second you start stopping or going uphill your MPG won’t remain the same and that’s why they aren’t economical :).

On motorway I have achieved 40MPG max and if you didn’t see from previous post I’m Stage 2+ KO3.
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Offline Pudding

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Re: Extremely poor MPG
« Reply #23 on: November 30, 2019, 05:45:26 PM »
My tank average is usually 18MPG. Combination of short journeys, stop/start driving slowing to a crawl of speedbumps and a lead foot once it gets up to temps. Can still get 400+ miles all motorway

Not comparable as everyone's driving style and road conditions will be different.

Indeed.  I've changed jobs recently and my 'miles to empty' is creeping closer to 400 a tank with every fill up, compared to 330 in my old job.
Black Edition 30 with manually selected cogs, a beefier clutch, some extra boost and them Whiteline thingies, otherwise standard.