MK5 Golf GTI

All Things Mk5 => Mk5 General Area => Topic started by: jakex181 on October 28, 2013, 09:37:05 am

Title: Poor MPG theory doesnt match actual
Post by: jakex181 on October 28, 2013, 09:37:05 am
Hi Guys,

I dont know if i have an issue here but...

My dash reads an overall average of 30mpg but when i use an online calculator or calculate it on paper it should actually read far less.

If i put £20 of fuel in at 1.29/litre (standard unleaded) i personally get 80 miles, but if im actually achieving 30mpg i should be seeing 100ish miles.

Could the lost 20 miles be because of starting/idling and similar things or could i have a deeper issue?
Title: Re: Poor MPG theory doesnt match actual
Post by: Marc-5-GTI on October 28, 2013, 10:13:28 am
The electronic read out is never going to be spot on..

If you're really troubled by it though, keep an eye on it.
Title: Re: Poor MPG theory doesnt match actual
Post by: GrayMK5GTI on October 28, 2013, 10:15:37 am
I think the accuracy can be adjusted with VCDS (Vag Com) if you can work out how far out it is manually.
Title: Re: Poor MPG theory doesnt match actual
Post by: jakex181 on October 28, 2013, 10:39:17 am
Ok cheers guys im just going to keep an eye on it for now and maybe start logging my fill ups
Title: Re: Poor MPG theory doesnt match actual
Post by: Leigh200sx on October 28, 2013, 10:49:10 am
Wish mine did 30mpg... I'm sure there is something wrong with It, I've had a Leon Cupra r running 270 Bhp and that was really really good... My gti is doing around 24mpg on the clock and over a long run maybe 30mpg
Title: Re: Poor MPG theory doesnt match actual
Post by: SurreyED30 on October 28, 2013, 10:53:53 am
^ +1 about the golf
Title: Re: Poor MPG theory doesnt match actual
Post by: alexmccabe on October 28, 2013, 11:36:37 am
I get nearly 38MPG+ out of mine on my drives to and from work. I hit up cruise control at 65mph and just relax. Saves me a lot of money. I am still convinced it is not running right as well, so tomorrow it is going to a garage for diagnostics. :) Maybe you should just get a diagnostic scan just to be sure.
Title: Re: Poor MPG theory doesnt match actual
Post by: xjay1337 on October 28, 2013, 11:59:08 am
I get around 36-38 on longer more chilled out drives.
Around 450 to a tank seems quite healthy to me.
Title: Re: Poor MPG theory doesnt match actual
Post by: Simon_2.0t on October 28, 2013, 12:00:47 pm
I get nearly 38MPG+ out of mine on my drives to and from work. I hit up cruise control at 65mph and just relax. Saves me a lot of money. I am still convinced it is not running right as well, so tomorrow it is going to a garage for diagnostics. :) Maybe you should just get a diagnostic scan just to be sure.

I was of the understanding using Cruise control not a great way to achieve good MPG as is constantly adjusting the fuel to maintain speed?

38 great figure tho  :happy2:
Title: Re: Poor MPG theory doesnt match actual
Post by: GrayMK5GTI on October 28, 2013, 12:04:42 pm
I get nearly 38MPG+ out of mine on my drives to and from work. I hit up cruise control at 65mph and just relax. Saves me a lot of money. I am still convinced it is not running right as well, so tomorrow it is going to a garage for diagnostics. :) Maybe you should just get a diagnostic scan just to be sure.

I was of the understanding using Cruise control not a great way to achieve good MPG as is constantly adjusting the fuel to maintain speed?

38 great figure tho  :happy2:

I get roughly the same with or without using Cruise Control  :happy2: Makes a journey so much easier
Title: Re: Poor MPG theory doesnt match actual
Post by: alexmccabe on October 28, 2013, 01:50:33 pm
I get nearly 38MPG+ out of mine on my drives to and from work. I hit up cruise control at 65mph and just relax. Saves me a lot of money. I am still convinced it is not running right as well, so tomorrow it is going to a garage for diagnostics. :) Maybe you should just get a diagnostic scan just to be sure.

I was of the understanding using Cruise control not a great way to achieve good MPG as is constantly adjusting the fuel to maintain speed?

38 great figure tho  :happy2:

I actually get less MPG out of it if I don't use the cruise control. It is a lot harder to maintain a constant speed using only your foot. I'd say it's well worth forking out for it if you haven't got it. Might save you some money.
Title: Re: Poor MPG theory doesnt match actual
Post by: jakex181 on October 28, 2013, 02:38:11 pm
How can i go about getting diagnostics done? do i just take it to any garage or must it be VW?
Title: Re: Poor MPG theory doesnt match actual
Post by: dodds-gttdi on October 28, 2013, 03:26:29 pm
Ok cheers guys im just going to keep an eye on it for now and maybe start logging my fill ups

A really useful (and free!) app I use is called Roadtrip. Handy wee thing to log all your fill-ups and calculates your MPG, etc, etc.  :happy2:
Title: Re: Poor MPG theory doesnt match actual
Post by: alexmccabe on October 28, 2013, 04:48:27 pm
How can i go about getting diagnostics done? do i just take it to any garage or must it be VW?

Many garages will charge you a ridiculous amount for it. Best bet is to find someone that can do it for you. There is bound to be somebody in your location that has VAGCOM.
Title: Re: Poor MPG theory doesnt match actual
Post by: Baz300 on October 28, 2013, 05:05:52 pm
Wish mine did 30mpg... I'm sure there is something wrong with It, I've had a Leon Cupra r running 270 Bhp and that was really really good... My gti is doing around 24mpg on the clock and over a long run maybe 30mpg

Have you checked the diverter valve?

My car was getting crap MPG before I replaced the torn one
Title: Re: Poor MPG theory doesnt match actual
Post by: Hurdy on October 28, 2013, 05:51:38 pm
I get around 36-38 on longer more chilled out drives.
Around 450 to a tank seems quite healthy to me.

Show off! :grin:

I'm lucky to see over 300 :sad1:
Title: Re: Poor MPG theory doesnt match actual
Post by: alexmccabe on October 28, 2013, 08:07:31 pm
I get around 36-38 on longer more chilled out drives.
Around 450 to a tank seems quite healthy to me.

Show off! :grin:

I'm lucky to see over 300 :sad1:

Haha, I get around that too, but like I said 65mph on cruise. Maybe just slow down every now and then? :p
Title: Re: Poor MPG theory doesnt match actual
Post by: GTI-Pirelli on October 28, 2013, 08:42:42 pm
387miles when i filled up earlier.

31 miles to work, about 80-90% motorway with the cruise set just under 70.
I have just started a new job as a consultant and can claim the miliage, hence driving like a pansy! Higher economy = more value.

USUALLY WASTED AT THE WEEKENDS!  It is a GTI!  :evilgrin:
Title: Re: Poor MPG theory doesnt match actual
Post by: sub39h on October 28, 2013, 09:37:39 pm
just an observation, but i get better fuel mileage with V-Power or Momentum than the cheap stuff. i still don't get mega miles though. about 35mpg is par for the course and i can expect 440mi out of a full tank over long distances.
Title: Re: Poor MPG theory doesnt match actual
Post by: Leigh200sx on October 29, 2013, 05:27:39 am
Wish mine did 30mpg... I'm sure there is something wrong with It, I've had a Leon Cupra r running 270 Bhp and that was really really good... My gti is doing around 24mpg on the clock and over a long run maybe 30mpg

Have you checked the diverter valve?

My car was getting crap MPG before I replaced the torn one


Yes it's just been replaced along with fuel pump cam follower and a full service with spark plugs ... It's really really bad on fuel :-( very disappointed with it.. I didn't buy the car for maximum mpg as I also have a mk5 golf gt Tdi but I never expected this shocking mpg. I'm 36 years old with 2 children, I drive extremely normal and currently showing 24.2mpg
Title: Re: Poor MPG theory doesnt match actual
Post by: Scottymon on October 29, 2013, 05:48:00 am
I would expect to see that sort of MPG for constant town driving or spirited.

What sort of MPG are you getting from the TDI?

I've got a Stage 1.5 with around 120k miles and can get 40 MPG on a run without much effort... Are you using decent fuel? VPower/ Tesco 99.?

Has the car been scanned?  Perhaps theres a fuelling issue.  Or MAF problem... ...
Title: Re: Poor MPG theory doesnt match actually
Post by: Leigh200sx on October 29, 2013, 06:21:55 am
I would expect to see that sort of MPG for constant town driving or spirited.

What sort of MPG are you getting from the TDI?

I've got a Stage 1.5 with around 120k miles and can get 40 MPG on a run without much effort... Are you using decent fuel? VPower/ Tesco 99.?

Has the car been scanned?  Perhaps theres a fuelling issue.  Or MAF problem... ...

Yes scanned and nothing ?? The gt Tdi is doing 44 mpg and that's town driving with a commute of 12 miles round trip.. As for fuel I only ever use she'll v power or tesco momentum.. I'm putting fuel in it ever 2 weeks and at around £55 at the last check I'm sure I had done less than 200 miles.. All though is can't be sure exactly how many miles I did due to having a new battery fitted during that time and resetting the trip.. I'm monitoring it now and will report back soon.. The car is a 1 previous owner with fvwsh and just showin 100,000 miles
Title: Re: Poor MPG theory doesnt match actually
Post by: dmac1969 on October 29, 2013, 09:15:01 pm
I would expect to see that sort of MPG for constant town driving or spirited.

What sort of MPG are you getting from the TDI?

I've got a Stage 1.5 with around 120k miles and can get 40 MPG on a run without much effort... Are you using decent fuel? VPower/ Tesco 99.?

Has the car been scanned?  Perhaps theres a fuelling issue.  Or MAF problem... ...

Yes scanned and nothing ?? The gt Tdi is doing 44 mpg and that's town driving with a commute of 12 miles round trip.. As for fuel I only ever use she'll v power or tesco momentum.. I'm putting fuel in it ever 2 weeks and at around £55 at the last check I'm sure I had done less than 200 miles.. All though is can't be sure exactly how many miles I did due to having a new battery fitted during that time and resetting the trip.. I'm monitoring it now and will report back soon.. The car is a 1 previous owner with fvwsh and just showin 100,000 miles

What does your computer show after a 60 to 70 MPH run on an A road or dual carriageway? I get 36 to 38 mpg every time out of mine , 24mpg sounds really low tbh , I get more than that around town!
Title: Re: Poor MPG theory doesnt match actual
Post by: Leigh200sx on October 29, 2013, 09:48:12 pm
I went for a run it tonight and reset the average mpg, I sat at 75mph on cruise control and if went up to 31.3mpg it's now dropped down to 28.6mpg and I assume it will continue to drop... I may take to the garage that serviced 2 weeks ago and ask them but the problem is due to me only owning the car for a few days before it went in I can't do a before and after comparison
Title: Re: Poor MPG theory doesnt match actual
Post by: alexmccabe on October 30, 2013, 10:27:34 am
I went for a run it tonight and reset the average mpg, I sat at 75mph on cruise control and if went up to 31.3mpg it's now dropped down to 28.6mpg and I assume it will continue to drop... I may take to the garage that serviced 2 weeks ago and ask them but the problem is due to me only owning the car for a few days before it went in I can't do a before and after comparison

For 75mph ~30mpg is about right. Try doing the same run again, but set cruise at 65mph.
Title: Re: Poor MPG theory doesnt match actual
Post by: Leigh200sx on October 30, 2013, 10:50:03 am
I went for a run it tonight and reset the average mpg, I sat at 75mph on cruise control and if went up to 31.3mpg it's now dropped down to 28.6mpg and I assume it will continue to drop... I may take to the garage that serviced 2 weeks ago and ask them but the problem is due to me only owning the car for a few days before it went in I can't do a before and after comparison

For 75mph ~30mpg is about right. Try doing the same run again, but set cruise at 65mph.

Driving to work today and it's now gone back to a usual low 24.2 mpg... Surely there is something wrong ?? Il have to look into next week
Title: Re: Poor MPG theory doesnt match actual
Post by: Scottymon on October 30, 2013, 10:56:21 am
What's the journey to work like?  Does the car get up to temp, is there a lot of stop start traffic... most 200+bhp petrol cars will be doing low/mid 20's in traffic and around town.

Have you tested the PCV?  What gap are the plugs at, are they the correct plugs? Are the coilpacks in good condition? Is the cam follower in good condition?  Are the tyres at correct pressures? Is a brake binding?
Title: Re: Poor MPG theory doesnt match actual
Post by: Leigh200sx on October 30, 2013, 12:36:12 pm
What's the journey to work like?  Does the car get up to temp, is there a lot of stop start traffic... most 200+bhp petrol cars will be doing low/mid 20's in traffic and around town.

Have you tested the PCV?  What gap are the plugs at, are they the correct plugs? Are the coilpacks in good condition? Is the cam follower in good condition?  Are the tyres at correct pressures? Is a brake binding?

The drive to work is 5.7 miles and only 2 roads a 30mph through the village then onto a 60mph road.. No stop starts and no traffic at all 5.20am.. Cam follower is new 2 weeks ago along with full service, new iridium plugs ,rev g diverter valve, 
Title: Re: Poor MPG theory doesnt match actual
Post by: trs888 on October 30, 2013, 07:06:08 pm
I get around 36-38 on longer more chilled out drives.
Around 450 to a tank seems quite healthy to me.


wow, i only get that if I'm doing ALL motorway though do set cruise to 80 tho (i know its not actually 80)

i do a mix of 70% city driving and 30% motorway tho. get about 28ish MPG which i think is ok, (about 300 miles to a tank)
didn't buy the car to be uber economical tho! else id have got a GT instead!  :happy2:
Title: Re: Poor MPG theory doesnt match actual
Post by: Leigh200sx on October 30, 2013, 07:31:03 pm
I get around 36-38 on longer more chilled out drives.
Around 450 to a tank seems quite healthy to me.


wow, i only get that if I'm doing ALL motorway though do set cruise to 80 tho (i know its not actually 80)

i do a mix of 70% city driving and 30% motorway tho. get about 28ish MPG which i think is ok, (about 300 miles to a tank)
didn't buy the car to be uber economical tho! else id have got a GT instead!  :happy2:

I didn't buy the car for mpg at all as I also have a gt Tdi... But mine seems a lot lower than my Leon Cupra r 225 which as a lot faster and more economical
Title: Re: Poor MPG theory doesnt match actual
Post by: trs888 on October 30, 2013, 07:39:41 pm
I get around 36-38 on longer more chilled out drives.
Around 450 to a tank seems quite healthy to me.


wow, i only get that if I'm doing ALL motorway though do set cruise to 80 tho (i know its not actually 80)

i do a mix of 70% city driving and 30% motorway tho. get about 28ish MPG which i think is ok, (about 300 miles to a tank)
didn't buy the car to be uber economical tho! else id have got a GT instead!  :happy2:

I didn't buy the car for mpg at all as I also have a gt Tdi... But mine seems a lot lower than my Leon Cupra r 225 which as a lot faster and more economical

theres surely some differences between geographical area i.e. hills etc and variations in manufacturing however small (possibility)????
Title: Re: Poor MPG theory doesnt match actual
Post by: alexmccabe on October 31, 2013, 08:45:35 am
I get around 36-38 on longer more chilled out drives.
Around 450 to a tank seems quite healthy to me.


wow, i only get that if I'm doing ALL motorway though do set cruise to 80 tho (i know its not actually 80)

i do a mix of 70% city driving and 30% motorway tho. get about 28ish MPG which i think is ok, (about 300 miles to a tank)
didn't buy the car to be uber economical tho! else id have got a GT instead!  :happy2:

I didn't buy the car for mpg at all as I also have a gt Tdi... But mine seems a lot lower than my Leon Cupra r 225 which as a lot faster and more economical

theres surely some differences between geographical area i.e. hills etc and variations in manufacturing however small (possibility)????

If there were fewer hills, my MPG would be higher. I have a real massive one on the A38 on the way to work and back, so yeah you are right.