Mpg Doing Odd Things

[mpg_junkie]

Hi All,

my journey to and from work takes me through a very flat part of the country on very straight 60mph roads. Typically I can sit in 6th gear at 60 mph and the MPG graph sits constantly around 75mpg. However, on a number of occasions over the last fortnight during this very consistent part of my journey the mpg has dropped to about 40-50mpg for between 13 and 18 minutes then shot back up to giving me around 75mpg again. If I touch the accelerator even lightly the current mpg drops to less than 50 immediately.

I assumed the car was doing some sort of regen of the diesel particulate filter, but if that is what this is why would it be doing it every 200 - 300 miles??

All opinions welcome.

Thanks,

MPG_Junkie

[MEP's Yaris GS]

DPF regen is exactly what it'll be. Every 200-300 miles sounds about right, it'll depend upon the cars useage pattern as to how regularly it does this.

[mpg_junkie]

I wonder if the frequency of the regen's has any correlation with what diesel I use? (I use supermarket fuel mostly).

[OldMan96]

Yh might well be the supermarket diesel, it is highly believed that branded diesel is far superior that supermarket. The actual diesel is identical and a lot of the time comes from the same local refinery but an additive pack is added to the tanker based upon who's fuel/tanker it is ie. Branded or Supermarket. Its this additive pack in the branded fuel that is said to make it burn cleaner and also clean the engine.

[Stuart303]

mpg_junkie,

Be warned, this is indeed a DPF regen, see the other threads I have been posting in "DPF Problem" & Yaris How "many mpg".

Mine is a long and bitter tale, still rumbling on, they changed the DPF last year in May because it was knackered. This last few weeks, the problems have started again.

The regen when my car was new occurred about every 500 miles, Then it got more frequent, eventually getting down to 120 miles between them.

At this point, the sump was also filling up with diesel fuel! This is a bad thing!

Check your oils, check the other threads, there is a Toyota fix for this, involves fitting a new short engine.

I have also been told by my dealership that the 5-year warranty doesn't cover the DPF, because it has a 3 year life. I hope this isn't true.