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Model specific boards => Golf mk2 => Topic started by: pullafacial on 30 October 2013, 09:38

Title: Bad mpg, running rich?
Post by: pullafacial on 30 October 2013, 09:38
Hi, I've recently purchased a mk2 gti 16v. The mfa is reading an average figure of around 33mpg which is what is expect. However, when i worked out what's it actually using, it's coming out at around 24mpg. From what I've read the mfa seems to be fairly accurate so what could cause this difference? My guy feeling is that it's running rich as it's lumpy on idle and smells I fuel a bit but would the mfa not take this in to consideration?

Any help would be greatly appreciated.

Thanks
Title: Re: Bad mpg, running rich?
Post by: weazgti on 30 October 2013, 09:55
Where did you read that the mfa is accurate  :grin:
Title: Re: Bad mpg, running rich?
Post by: pullafacial on 30 October 2013, 11:50
Read it somewhere online. Someone had done an mpg review and found his mfa to be accurate to less than 1%.
I guess what I'm getting at is could a rich running engine cause such a low return or should I be looking for something else?

Thanks again
Title: Re: Bad mpg, running rich?
Post by: dragonfly on 30 October 2013, 14:21
Have you checked for fuel leaks?
Title: Re: Bad mpg, running rich?
Post by: pullafacial on 30 October 2013, 15:40
Hi, looks like there is a fuel leak coming from above the fuel pump assembly. Drips about once every 10 seconds when running but still smells even when not been used for hours.
Title: Re: Bad mpg, running rich?
Post by: oakgreener on 30 October 2013, 16:44
The MFA works on reading the vacuum in the intake. As long as the engine is set up OK as regards to mixture and timing the MFA will be somewhere handy. Not accurate. If you have fuel leaks it will be out.
Title: Re: Bad mpg, running rich?
Post by: Gambit on 30 October 2013, 17:56
set the CO%, if its got a lumpy idle then it needs setup.
Title: Re: Bad mpg, running rich?
Post by: pullafacial on 29 November 2013, 20:07
So, fuel leak fixed and still have same problem.

Anyone got any other ideas?

Thanks
Title: Re: Bad mpg, running rich?
Post by: Sgt_Lemon on 29 November 2013, 21:14
Get it running smooth, timed correctly, mix done. No fuel or vac leaks. A good spark, even compression.
Title: Re: Bad mpg, running rich?
Post by: JC on 30 November 2013, 22:49
every MFA will have a different % of accurancy.

They are getting old, as is the associated pipework.

only way of doing a proper MPG is to brim it, drive it, brim it, record figures, repeat.

THEN you can work out your mpg  ( even then your speedo could be over or under reading so could still be miles out )


its a mk2, fill it and drive it and enjoy   :smiley:
Title: Re: Bad mpg, running rich?
Post by: gazareth on 01 December 2013, 21:08
yes and if you don't enjoy every second of driving your mk2 then you are going to have to sell it to someone that will :grin:
Title: Re: Bad mpg, running rich?
Post by: Waspy on 01 December 2013, 22:21
Quote from: Chuff on 30 November 2013, 22:49
its a mk2, fill it and drive it and enjoy   :smiley:

Quote is getting signatured.
Title: Re: Bad mpg, running rich?
Post by: rich1977 on 02 December 2013, 19:30
Well the mfa on my new one reads 11mpg  :grin: :grin:

Luckily I know its faulty.
Title: Re: Bad mpg, running rich?
Post by: Sgt_Lemon on 02 December 2013, 21:12
Mine under reads slightly, I know I can get 43 mpg if I cruise around 85 down the motor way. Brimming it and recording the litres used compared to the miles traveled though is the only true reading. If your isn't miles off you can use it as a rough guide to see how your drive style affects it. Don't forget there are two settings also, one reads your current mpg but is slow to clock up even if you are economical and the second is your overall average. Once on the mpg setting flick between 1-2 to see how your comparing.