2012 to 2014 Yaris D-4D poor fuel economy

[nigel-surtees69]

I have just bought a 2013 Yaris D-4D. Im very disappointed with the fuel consumption. I previously owned a 2004 Yaris D-4D which returned 65 mpg, calculated by filling the tank regarding mileage and refilling tank. I did 70,000 miles and it returned 65mpg consistently.I had a 2010 Yaris D-4D which returned similar figures also.

The 2013 Yaris is returning 56 mpg on the same journey in the same circumstances. To my dismay on looking up the fuel figures the 2013 quotes a combined figure only and its 52mpg.

Im wondering if there are any Toyota technicians out there who can tell me what changed on the 2012 to 2014 model Yaris D-4D. I assume that the basic engine is the same.

Is there an extra emissions gadget installed? I would like to improve the mpg, i am sure it must be possible.

[FROSTYBALLS]

Your 2010 Yaris may or may not have had a diesel particulate filter, but the 2013 Yaris certainly has one.

[nigel-surtees69]

So does a particulate filter affect mpg?

 

[flash22]

emission controls on diesels strangle the engine you may need to adjust your driving style too - try changing up a bit earlier rather than taking it up the rev range

[nigel-surtees69]

The later Yaris diesels are also very economic so it cant be just that new regs for emissions. Im hoping someone on the forum knows what has changed on this particular model year and has affected the mpg so badly.

[flash22]

There are so many factors like how has it been looked after, how has it been serviced, what fuel has been used, is it doing a full regen cycle, when was the fuel filter changed and many other variables

euro 5 and 6 really strangle diesels to get them within the allowed specs DPF's have been a real issue costing north of £2000 on some cars

Diesel doesn't make sense any more unless you're doing 18k+ miles a year short trips kill them as they don't get hot enough to burn the particulates off

[Devon Aygo]

A diesel particulate filter affects both engine power, requiring more fuel to achieve a similar power as a car without but also requires fuel to regenerate the Diesel particulate filter.

What is your normal driving? I ask because your driving habits will affect how often the DPF has to regenerate which it does in two ways:

Passive, where high engine speeds & high temp will allow accumulated Particulate matter to burn off without the addition of fuel.

Active, where the car will add diesel fuel into the DPF to burn off to PM

If the car predominantly does more slower, stop/start driving then the DPF will not passively regenerate and will require more Active regeneration's using up more diesel, as the DPF ages the time between regeneration's will also start to reduce as the DPF's PM capacity slowly reduces, again requiring more active regeneration's 

 

[nigel-surtees69]

my journey is commuting 25 miles each way on a motorway at steady 50-70 speeds. I understand and accept all the comments re driving style, journey type etc. However if you look at the book figures for all Yaris diesels up to 2012 the combined mpg is 67mpg. if you look at 2014 and onward models its combined mpg is 70-80mpg

The 2013/14 model stands out as very poor in comparison to all other model years at a combined mpg of 52. This leads me to believe that the emission control system or similar was tweaked/changed and that has affected fuel economy on 2013/14 model year cars. The car i currently run is a 2013 model with full Toyota service history and 52000 miles on the clock. It is immaculate and appears to have been very well maintained. I bought it from a Toyota dealer.

I have done the same journey now for 6 years and 80,000 miles with very consistent mpg around the 65mpg mark.

[FROSTYBALLS]

For the 2014 model year, the diesel engine was tweaked to lower emissions, which may have had an effect on economy.

[nigel-surtees69]

Thanks FrostyBalls. Do you know what specific changes/additions were made?

[nigel-surtees69]

12 hours ago, FROSTYBALLS said:

For the 2014 model year, the diesel engine was tweaked to lower emissions, which may have had an effect on economy.

Thanks FrostyBalls. Do you know what specific changes/additions were made? Or do you know where i could get that information?

[flash22]

2014 is the facelift the only things that spring to mind are an ecu update or a change to the gearbox ratios, what size tires/rims does the car have

[Madasafish]

First thing to do: check rear brakes are not binding.(drums so quite possible)

Then front brakes..(less likely)

[flash22]

2 hours ago, Madasafish said:

First thing to do: check rear brakes are not binding.(drums so quite possible)

Then front brakes..(less likely)

Did the diesels not get disc's all round ?

Edit. Just looked it up in the brakebook they had disc's or drums on the rear (model specific)

[bathtub tom]

Perhaps the OP's found the reason the previous owner flogged it?

 

[stevecrvn]

Our 2015 auris has the 1.4 d4d enging and always gives between 57 - 58 mpg is currently putting my hybrid to shame.

[mrpj]

The Auris is a bigger car but I always achieved over 60mpg with the 1.4d4d Yaris (2010 Mk2) I owned.

Not far behind wih my current 1.33l petrol Yaris (2014 Mk 3) though. Consistently over 50mpg (only just 😎).

[mrpj]

20 hours ago, Madasafish said:

First thing to do: check rear brakes are not binding.(drums so quite possible)

Then front brakes..(less likely)

Then tyre pressures.

[Madasafish]

You did not mention the mileage.

 

If it has done few miles - less than 10k a year - and used only on short runs, it may be all carbonned up and the catalyst and dpf may be partially blocked...

Try an Italian tune up.. at least 30miles with rpm exceeding 3,000     flat out rpm is better  at all times. This will heat up the engine and could help clear it out.. 

[bearcub24]

Mine is a 2016 (icon I think) and it only has discs up front, the last time I did an mpg check it was 57mpg, the computer says 59.5mpg. 

[drusoider]

I have just bought a 2013 Yaris D-4D. Im very disappointed with the fuel consumption. I previously owned a 2004 Yaris D-4D which returned 65 mpg, calculated by filling the tank regarding mileage and refilling tank. I did 70,000 miles and it returned 65mpg consistently.I had a 2010 Yaris D-4D which returned similar figures also.
The 2013 Yaris is returning 56 mpg on the same journey in the same circumstances. To my dismay on looking up the fuel figures the 2013 quotes a combined figure only and its 52mpg.
Im wondering if there are any Toyota technicians out there who can tell me what changed on the 2012 to 2014 model Yaris D-4D. I assume that the basic engine is the same.
Is there an extra emissions gadget installed? I would like to improve the mpg, i am sure it must be possible.

Did you find the problem? I got the same mpg and did a full clean of catalytic converter and helped a little.

Sent from my Redmi Note 4 using Tapatalk

[nigel-surtees69]

On 12/21/2019 at 9:00 AM, drusoider said:

Did you find the problem? I got the same mpg and did a full clean of catalytic converter and helped a little.

Sent from my Redmi Note 4 using Tapatalk
 

I haven't tracked the problem down yet. I say problem but its more a case of what changes were made to this model year to make it less efficient that previous and post model yearcars. Mine is getting the mpg the official figures suggest so i cant complain to the dealer. I suspect theres emission control gadgetry involved. I will update you if i get to the bottom of it

[flash22]

Ask a main stealer if there are any ecu updates available for your car