Author Topic: Low MPG in 1.6 D 2nd Gen  (Read 2235 times)

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Offline Hero_uk1

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  • Mazda 3, 1.6, 2012, Dolphin Grey
  • Body: Hatchback
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  • Engine: 1.6L
  • Fuel: Diesel
  • Model: Mazda 3
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  • Year: 2012
Re: Low MPG in 1.6 D 2nd Gen
« Reply #15 on: September 17, 2018, 11:03:57 AM »
It does sound abnormally low; especially your motorway figure. I've been averaging high fifties (brim to brim) over the summer with a mixture of mainly motorway commuting with a couple of miles of urban driving at either end. I also just got 62mpg out of mainly motorway driving from Devon to Newcastle with a full load and family on board. The lowest I've recorded in this car was around 45.2mpg, and that was in the depths of winter this year (with all that snow).

It's virtually impossible to figure out where the fault could lie. Could there be a leak? Is there a fault with the ECU or the MAF? Would a DPF close to blocking cause a drop in MPG? Away from hardware, the only thing I could suggest would be to run through a can of either BG244 or Archoil AR6400-D MAX (both of which seem to get decent reviews) for a tank followed by a shot of Millers Ecomax a tank or two later. Also, some people swear by services like Terraclean or Hydroflow (for about £100). The Terraclean did nothing for my own car but then there wasn't a particular 'fault' for it to work on. I must say I am sceptical about such products myself but, again, my powertrain seems to be in decent condition for the age of vehicle and I know it was well looked after from new by the previous owner. Some consumer reviews indicate improvements in mpg in using them but it is not always clear how they have arrived at those conclusions (I suspect many go off the numbers provided by the computer rather than brim to brim measurements over time).


Ok so i have ordered Archoil AR6400-D MAX for my car and will post results.

OK the results are:

After putting Archoil AR6400-D MAX  i got 50mpg!!! round town :D

With just BP Diesel i get 42MPG!!!! round town

Does this mean my injectors or fuel filter need replacing because the Archoil AR6400-D MAX is manily to clean the fuel filter and injectors?



Coming from Honda Civic

Offline red_imps_2003

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Re: Low MPG in 1.6 D 2nd Gen
« Reply #16 on: September 17, 2018, 12:41:01 PM »
Wow! Those are really interesting results. If the previous low mpg has been prevalent over several tanks, as your other posts suggest, then it does look as though the fuel additive might actually have done something. Of course, the proof will be in whether this is now sustained over future refills. In theory, you shouldn't have to keep using the [hugely expensive] AR6400-D MAX in future tanks to sustain the improvements. My understanding is that this kind of thing is designed as a one-shot treatment (or, at least, to be used infrequently) to clean the fuel and filter systems out a bit by reducing buildup of carbon deposits rather than by improving the quality of the fuel itself. Archoil sell another product that, although expensive at the outset, is designed to be added a cap-full at a time to each tank and so last a lot longer. Or you could use the Millers equivalent (Diesel Power Ecomax). I currently stick a dose of the Milllers product in every second tank or so. Both supposedly replicate the additives contained in the premium diesels sold by the likes of Shell and BP but are cheaper by two or three quid a tank.

Please do let us know if this massive improvement in mpg is sustained. I'm naturally skeptical of fuel/oil additives but not to the point of being totally dismissive of evidence (however anecdotal) of potential efficacy. Like I say, I have tried out all sorts myself just to see what happens.
So I was stood there trying to work out why the cricket ball was getting larger and larger...and then it hit me.

Offline Hero_uk1

  • TS Class
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  • Posts: 29
  • Gender: Male
  • Mazda 3, 1.6, 2012, Dolphin Grey
  • Body: Hatchback
  • Colour: Carbon Grey (28B) Metallic
  • Engine: 1.6L
  • Fuel: Diesel
  • Model: Mazda 3
  • Transmission: Manual
  • Trim: Sport
  • Year: 2012
Re: Low MPG in 1.6 D 2nd Gen
« Reply #17 on: September 24, 2018, 12:38:04 PM »
Wow! Those are really interesting results. If the previous low mpg has been prevalent over several tanks, as your other posts suggest, then it does look as though the fuel additive might actually have done something. Of course, the proof will be in whether this is now sustained over future refills. In theory, you shouldn't have to keep using the [hugely expensive] AR6400-D MAX in future tanks to sustain the improvements. My understanding is that this kind of thing is designed as a one-shot treatment (or, at least, to be used infrequently) to clean the fuel and filter systems out a bit by reducing buildup of carbon deposits rather than by improving the quality of the fuel itself. Archoil sell another product that, although expensive at the outset, is designed to be added a cap-full at a time to each tank and so last a lot longer. Or you could use the Millers equivalent (Diesel Power Ecomax). I currently stick a dose of the Milllers product in every second tank or so. Both supposedly replicate the additives contained in the premium diesels sold by the likes of Shell and BP but are cheaper by two or three quid a tank.

Please do let us know if this massive improvement in mpg is sustained. I'm naturally skeptical of fuel/oil additives but not to the point of being totally dismissive of evidence (however anecdotal) of potential efficacy. Like I say, I have tried out all sorts myself just to see what happens.

OK another week has gone and im getting 41.8 MPG round town.

I have noticed abit of oil in cold side of the turbo (about table spoon), is this normal? I know turbos need to have little bit of oil to lubricate bearings etc but just wondering if that might be cause of low MPG.
Coming from Honda Civic

Offline red_imps_2003

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  • Model: Mazda 3
  • Transmission: Manual
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  • Year: 2009
Re: Low MPG in 1.6 D 2nd Gen
« Reply #18 on: September 24, 2018, 05:35:07 PM »
Bummer that improvements were not sustained. I wonder why it shot up in that specific window?

A tablespoon of oil anywhere on the outside of components sounds a bit dodgy to me. I'm afraid I'm not mechanically minded enough to know whether leaks in the turbo area could translate into poor fuel economy though. Sorry.
So I was stood there trying to work out why the cricket ball was getting larger and larger...and then it hit me.

Offline Hero_uk1

  • TS Class
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  • Posts: 29
  • Gender: Male
  • Mazda 3, 1.6, 2012, Dolphin Grey
  • Body: Hatchback
  • Colour: Carbon Grey (28B) Metallic
  • Engine: 1.6L
  • Fuel: Diesel
  • Model: Mazda 3
  • Transmission: Manual
  • Trim: Sport
  • Year: 2012
Re: Low MPG in 1.6 D 2nd Gen
« Reply #19 on: October 02, 2018, 12:43:57 PM »
OK after another 321 miles of town driving i got 43MPG using BP Fuel. Looks like i'll have to  accept the fact im only going to get low 40 MPG round town in my mazda 3  :-\ :-\
Coming from Honda Civic

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Re: Low MPG in 1.6 D 2nd Gen
« Reply #19 on: October 02, 2018, 12:43:57 PM »