MK5 Golf GTI - Fuel Economy!!

[E8RNX]

Hi there guys!

I have a question about fuel economy and (I know there’s many, many threads out there for fuel economy already).

Basically my Golf GTI which I just recently bought has ridiculously low fuel economy - I literally get about 13 MPG average (city driving). From what I’ve read on forums I should be getting about 20’s in city??

I didn’t buy this car for fuel economy at all so I still think every penny is worth it! It’s great fun but the MPG I’m getting is absolutely ridiculous. I also have a VR6 Golf 2.8 which gets much better fuel economy and I’m so confused?!

I know that my MAF sensor is playing up as if I push it in then the engine misfires so I’m about to get that replaced. The fuel economy could be down due to the MAF sensor being faulty from what I’ve heard anyway but it still shouldn’t be this low!

Has anyone had this? This ultra low fuel economy on a golf 2.0 TFSI.

Also to add the car is fully and totally stock, it’s a 55 Plate Axx engine code and nothing has been touched ever, not even a remap.

And finally I use 99 RON only - either 99 Tesco Momentum or VPOWER. Car has also been fully serviced with the cam follower changed too and also little bits like the temperature sensor.

Thanks! Would appreciate what you guys think :)

[PKGTI]

Check the thermostat is working correctly, my car was running cold which meant it was using more fuel, only low to mid 20’s. Since having it replaced my car runs at 90 degrees and I now see late 20’s and up to 34mpg on a run.

[neilw]

Check the thermostat is working correctly, my car was running cold which meant it was using more fuel, only low to mid 20’s. Since having it replaced my car runs at 90 degrees and I now see late 20’s and up to 34mpg on a run.

Yup that's what mine does. I can get up to 40 on a long slow motorway run in light traffic.

[Octoparrot]

Is your low mpg just going by what the trip computer says or have you done your own calculations?

[E8RNX]

@PKGTI - I’ll get that checked out - although I think thermostat is fine as temperature goes to 90 quickly within 10+ minutes of driving or so.

@neilw - Wow 40MPG!!!!!! That doesn’t even seem possible to on my car! Right now it’s as if I’m driving a G63 AMG lol.

@Octoparrot - Okay so the 13 MPG figure I quoted is from the trip computer.. The trip computer always shows me stupid MPG figures - Extremely Low.

Calculating the MPG myself after logging miles and how much I filled up I still get around 15MPG maybe and let me add how that’s even sensible driving. When I put my foot down it just eats.

[E8RNX]

Oh and guys let me add. Checking fault codes using a proper Snap-on Diagnostics computer I have found a boost fault code. I don’t believe it’s a leak but something to do with wiring as one of the wiring rooms in the engine bay seems tampered with.

I’m going to check every wire in the engine bay, I’m hoping I find the issue and get better MPG figures! But also full power.

[muff1991]

Start with MAF - either clean or replace that's a big factor.. but as an idea to double check things...

rubbish coils, spark plugs (check gap 100%), dodgy PCV, DV, air vacuum/boost leaks, fuel filter, tyre pressures, tracking and lambda sensors.. amongst an even bigger list, I've seen and heard of all these causing bad MPG.

maybe also run some kind of injector cleaner through it.

[colesey]

They are thirsty buggers on short runs - high teens is what we get, with a best of 42 mpg on a long run. All good points to check from the other guys and I would recommend a tank of BG44k also.

[Dogma]

I thought the same after getting my ed30 comparing to my Corrado vr6.

The best I’ve ever got out of a tank is 340miles on a long journey on the ed30, which I thought was pants for a modern car, but it’s fast car so you have to expect it I guess.  Right foot and all that.


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[E8RNX]

Thanks for all the reply’s guys. It’s so annoying that I can’t post without a moderator checking my comment first lol otherwise I’ve been replying straight after your messages.

Okay update guys: the temperature sensor is fine, my dad actually got it replaced last week and didn’t tell me 

@muff1991 Thanks for that amazing list.. I will definitely be sure to check all these things and replace. MAF Sensor defo needs changing so that’s first. Like I said earlier for some reason when I plug my current MAF sensor connector in fully the engine starts misfiring. Therefore I’ve left the connector like that too since I’ve bought the car (previous owner left it halfway into the slot too so I didn’t realise).

[muff1991]

Thanks for all the reply’s guys. It’s so annoying that I can’t post without a moderator checking my comment first lol otherwise I’ve been replying straight after your messages.

Okay update guys: the temperature sensor is fine, my dad actually got it replaced last week and didn’t tell me 

@muff1991 Thanks for that amazing list.. I will definitely be sure to check all these things and replace. MAF Sensor defo needs changing so that’s first. Like I said earlier for some reason when I plug my current MAF sensor connector in fully the engine starts misfiring. Therefore I’ve left the connector like that too since I’ve bought the car (previous owner left it halfway into the slot too so I didn’t realise).

No worries at all mate, it’s not a definite answer but it’s a start. 
I would strongly recommend you replace the MAF. If the cars running when you unplug it (running on basic settings) and running rough with its connected then that’s 100% faulty and almost definitely your mpg problem.

Hopefully you’ll be able to skip the moderator bit soon once you’ve done a few posts.

Replace and report back with some better mpg readings :-)


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[E8RNX]

@muff1991

Update for all you guys!

Just replaced my MAF sensor, engine now doesn’t misfire and getting much much better MPG readings!

MAF sensor was from TPS, I tried one from Europarts as they were giving lifetime warranty too however that didn’t fit.

Thanks for all the help, glad I won’t need to fill up every few days anymore 

[muff1991]

@muff1991

Update for all you guys!

Just replaced my MAF sensor, engine now doesn’t misfire and getting much much better MPG readings!

MAF sensor was from TPS, I tried one from Europarts as they were giving lifetime warranty too however that didn’t fit.

Thanks for all the help, glad I won’t need to fill up every few days anymore 

Glad you got it sorted mate, made sense to be the MAF. You are better off with the genuine part for that kind of thing. Much better quality and will provide your ECU with accurate readings. Also will last longer that Euros one.
Enjoy your better mpg. They are not great on fuel, but they do provide pretty good mpg for what they are. Can’t complain, best of both worlds with these cars. Enjoy :-)


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[pudding]

Faulty sensors aside, this is a classic case of expectations and manufacturers [misleading] claims versus reality 

If I drive my ED30 very slowly I can get 400 miles from a tank, which is only 33mpg.  By very slowly, I mean stints of being stuck behind HGV elephant races and never giving it more than 30% throttle, and never exceeding 70mph.  So, by driving a GTI in a very un GTI fashion, it still can't meet the manufacturer's claims.

That's a long term average by the way, verified with pump calculations.

If I drive it how GTIs should be driven, and cruise at 85-90mph where possible, the long term average drops to 28mpg.

To be fair, 28mpg isn't bad for a 300hp turbo hatch.  300hp cars from the 90s would be lucky to return 20mpg.

[PKGTI]

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.