MK5 Golf GTI - Fuel Economy!!

[colesey]

I think the amount go vs real life fuel consumption is brilliant considering the age of design. I can’t imagine a Mk7 being that much better real world.

Autocar ran a long term test on a mk7 GTi over several months and reported regularly seeing more than 40mpg.

[pudding]

I think the amount go vs real life fuel consumption is brilliant considering the age of design. I can’t imagine a Mk7 being that much better real world.

Autocar ran a long term test on a mk7 GTi over several months and reported regularly seeing more than 40mpg.

Whereas 173 real world people claim 34.8mpg.  VW claim 38 combined.

https://www.honestjohn.co.uk/realmpg/volkswagen/golf-vii-gti-2013

But quite....the performance per gallon isn't bad at all for a 15 year old car.  VAG were early adopters of DI.  It still has it's drawbacks, but it's improved a lot since 2004!

[colesey]

I think the amount go vs real life fuel consumption is brilliant considering the age of design. I can’t imagine a Mk7 being that much better real world.

Autocar ran a long term test on a mk7 GTi over several months and reported regularly seeing more than 40mpg.

Whereas 173 real world people claim 34.8mpg.  VW claim 38 combined.

https://www.honestjohn.co.uk/realmpg/volkswagen/golf-vii-gti-2013

But quite....the performance per gallon isn't bad at all for a 15 year old car.  VAG were early adopters of DI.  It still has it's drawbacks, but it's improved a lot since 2004!

Best go tell autocar that they got it wrong Kev, not me!

[E8RNX]

Yes definitely. They aren’t the best with fuel economy and defo not what the manufacturer figures are. But! The GTI is just so much fun and every penny is so worth it. Mine is just stock right now 200HP and I still haven’t got bored of the power, always beating people off the line when they think it’s a standard Golf.. lol 

[loop]

My GT only does around 12mpg in traffic, in first and second gear, stop and start, when cold. But I have got 44 mpg out of it in summer when doing 50-60 mph over prolonged periods!  Recent average is 27-28 mpg.


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[PKGTI]

Managed 36 MPG on a mixed 30 mile run today.  Considering that the journey included a couple of brief 90mpg plus moments I think that the MPG is really good on theses cars! Worth mentioned I am only running my car on Esso 97 Ron fuel.

[Chesto18]

Might be worth noting, I just changed my fuel filter on a 117k ‘08 plate which I don’t think had ever been changed before and my MPG has shot up from 26-27 ish on medium distance run (20-30mins of stop start and B road cruising) to 32ish MPG.

Car seems to pick up a little better too.

[rich83]

Mines doing 25.5mpg according to the last 4 fill ups on Fuely.

[KJNGTi]

My thermostat was bad and was getting 30mpg or more... I’ll check it’s average but believe it’s near 32mpg at the moment

[E8RNX]

All you guys get amazing MPG lol. Makes me think what is wrong with my baby 😂😅.
Update on my GTI:

I changed my MAF and MPG improved slightly, not a lot - I felt like the car was obviously running much smoother though.

Next if I didn’t already say on earlier posts I was getting an underboost code (P0299). >> I researched about this and found it to be the diverter valve. I ordered a rev G from Awesome GTI and found that my current one was all torn and ripped in the rubber seals hence the leak.

Now my car is pulling like a plane!!!!!!!!!!!! It is literally rapid, so much so that it just wheelspins constantly - think I need new tyres.

**
After all this my car is pulling exactly how it should and defo getting the right power BUT!! I’m still getting 15MPG :(. And btw that’s not me constantly flooring it, even if I drive nice and calm like an old man in 4th, 5th and 6th gear I’m getting 16 MPG max.

So next I am installing an induction kit (tomorrow) and see if that improves anything. My current standard air box doesn’t have a pipe running all the way to the front of the car like it should so maybe not working efficiently.

If MPG still doesn’t improve then I am going to switch up to R8 coils and new spark plugs which I was going to do anyway and see how she does. Also I’m going to check PCV... there’s no sign to say it’s not working properly but worth a check.

Thanks for all the help guys! I’ll keep you updated.

[muff1991]

I really don't think a cold air intake will improve mpg.. if anything it will make it worse as more airs going in (so MAF etc will introduce more fuel to compensate) not hugely much though.

so when you say 15mpg.. that's what your screen is saying right, have you worked out your exact mpg as in what you actually get from the amount of fuel you have put in?

are you aware of the number 1 and number 2 screens for the cluster (I don't know the exact technical name) but number 2 will display your overall mpg, speed etc and number 1 will be that journeys mpg etc etc. ? if you're not aware about this then its a button under the wiper stalk.. press it once and youll see on the dash top right corner.. 1 or 2 will show.

replacing the PCV is never a bad thing, at least once a new one is in you know that's eliminated. what's your temperature gauge reading.. normal 90?

[pudding]

If 15mpg was the actual long term average, there would be exhaust soot stuck to the back of the car!

You've changed the MAF and diverter valve.  Give it time to rebuild the mpg calculations.  What does the mpg range say a few minutes after a fill up? 

Agreed with Muff, don't waste money on mods until the engine is running as it should.  The missing snorkel won't cause a ~20mpg loss, but it would be better to have it there to make sure it's not pulling in warm air from the radiator.  You can still get it from VW, it's not much money.

[E8RNX]

@muff1991

Yes I am aware of the both screens. Number one is just the trip and number two is for the past 99 hours of driving or so. With mine you change using the steering wheel!

So yeah on the high line display it’s displaying 13.2 MPG on number 2 and generally for every trip it says around 13-15 MPG.

I have also worked it out using calculations (fuel economy calculator website).... Basically to show you how bad it is I filled a full tank and a week later after about 150 miles the needs was back on reserves and I got about 167 total from the full tank.

Now my car shows no codes at all and no signs of anything like leaks. It is pulling like crazy too!

One thing I can say that I don’t know when has been changed is the fuel filter, I don’t know how big of a difference that can make though as generally petrol is clean as I’ve heard?

Overall I know it’s very very bad as my friend has an edition 30 and he says how he generally gets about 40-50 miles per £10 of fuel. So with the GTI’s 55 litre he gets about 300 miles odd.

[Chesto18]

@muff1991

Yes I am aware of the both screens. Number one is just the trip and number two is for the past 99 hours of driving or so. With mine you change using the steering wheel!

So yeah on the high line display it’s displaying 13.2 MPG on number 2 and generally for every trip it says around 13-15 MPG.

I have also worked it out using calculations (fuel economy calculator website).... Basically to show you how bad it is I filled a full tank and a week later after about 150 miles the needs was back on reserves and I got about 167 total from the full tank.

Now my car shows no codes at all and no signs of anything like leaks. It is pulling like crazy too!

One thing I can say that I don’t know when has been changed is the fuel filter, I don’t know how big of a difference that can make though as generally petrol is clean as I’ve heard?

Overall I know it’s very very bad as my friend has an edition 30 and he says how he generally gets about 40-50 miles per £10 of fuel. So with the GTI’s 55 litre he gets about 300 miles odd.

Sounds like there is definitely an issue. Take it back to basics. Are your wheels hot after a drive? If a caliper is sticking this will affect performance and MPG.

MAF has been changed and diverter valve. To check PCV pull out dipstick momentarily. If the engine sounds like it’s about to stall, it’s ok.

Fuel filter will improve things if it’s never been changed but not by an extra 15mpg.

Reset the car, disconnect the battery and reset the clocks and go for a drive. See what the new calculations are.

Someone else can advise if there is another sensor that can affect MPG so severely, but my initial thoughts would be MAF which you’ve done.

Are you sure there isn’t a leak? Keep engine running and look under bonnet as well.

How does it start? Injectors would be my next thought after all the above but I’d expect other symptoms.

[muff1991]

This is becoming a tricky one... we’re running out of ideas haha.

Glad you knew what I meant by the screens, wasn’t teaching you how to suck eggs etc I was just ruling things out yano.

That fueling is definitely messed up tho, you literally are getting half of what you should be really. If you came and said yeah well I floor it everywhere I’d understand, but even to drive like a granny and still get that.. it’s really bad! As @chesto mentioned it could be injectors dumping too much fuel but other symptoms would arise if you ask me. But then you never know with these cars!
Have you got VCDS? Where are you based?
And you say.. other than bad bad mpg, the car drives and idles absolutely perfect?
I wonder if the HPFP is releasing too much fuel or sumin, when was the follower last changed? a fuel filter change may help but again as @chesto said... not enough to warrant you 15mpg back! It’s really a weird one tbh.
I know these cars are not great on fuel, but to say 25+ on a steady granny run is MORE than reasonable if you ask me!
Don’t give up mate, we’ll get to the bottom of it one way or another.
Defo worth jacking up to make sure all wheels are spinning freely tho!


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