Disappointing Low Mpg

[byzantian]

Recently bought a 1.0 VVT IQ, three years old with 18,000 miles. But the best fuel economy I get in town on shortish journeys, driven carefully, is no more than 42 mpg (according to the dashboard indicator). I was expecting a lot more than this. Is there a problem somewhere? I recently fitted four new tyres to the car. Interested to hear other owners' experience.

[FROSTYBALLS]

The Real MPG info on the Honest John website shows that owners are getting between 47 and 60 - http://www.honestjohn.co.uk/realmpg/toyota/iq-2008/10-vvt-i

Short journeys, city traffic, and the colder weather will all have an effect.

What fuel economy rating were your new tyres?

What consumption were you anticipating?

[byzantian]

Thanks for your reply. i don't know what the tyre rating is but I was expecting something in excess of 60 mpg. I'll guess i get that on a run.

Cheers

[Grumpy Cabbie]

Tyres make a difference. Fit winter tyres with an F rating and whilst great for snow grip, they may not be so good for fuel economy. That's why they now issue an economy rating. A rated LRR tyres make a big difference to economy and can offer great grip too.

Tyre pressures make a difference as well. They can change as weather gets colder or warmer (air becomes more or less dense) so always check them. A couple psi under and that can affect economy. Too high and that can affect grip in the wet.

Try 0w20 oil at your next service as that too is stipulated by Toyota, rather than the thicker 5w30 oil that Halford and Duckhams try to suggest.

But fuel economy is one of those personal things. Your town driving might be totally different to mine. Others might have a free flowing town with great traffic management, others may not. Anything over 40 mpg in cold weather is good.

ps. check your oil level and check the top of the oil cap. If the car has done a low mileage it might be full of gunk: the IQ can be prone to this. If so, get it changed to 0w20 early and keep an eye on it. It could be a sign of a blown head gasket, but the IQ is just prone to condensation due to running cold, so chances are it's not as serious. Keep an eye on your coolant level and if it's fine you should be too.

[Alexandru]

The worst i got it was 48 mpg , but on the motorway is 58,59 mpg

[AyeupIQ]

I drive a 1.0 at2 auto. On average and all short trips I average 41/43 mpg on a good run it's about 54mpg. I warm weather I get about 8% more

[dave hendy]

That's the good thing about my Yaris diesel the fuel economy varies a lot less than a petrol on different journeys, I always get 50-55 mpg whether it's on my 7.5 mile journey to work or a 100 mile trip to the NEC!

When my wife had a 1.3 Yaris petrol and had a 2 mile journey to work she used to get 34 mpg where it had been more like 43 mpg when she had a 10 mile commute.

I hope to get about 50 mpg when I get my iQ2 in a weeks time?

[Grumpy Cabbie]

What's the mpg allowance to convert the cost of diesel mpg to the cheaper petrol mpg equivalent? Is it 5%?

So 50 mpg diesel is 48 mpg petrol equivalent? A petrol gets 43 mpg, so only 5 mpg less for a car that's cheaper to buy, cheaper to run and needs servicing less often. And gives out between 5 and 200 times less NOx ;)

[Cyker]

I didn't think 40-odd mpg is that bad for a petrol engine if it's only doing really short town journeys.

That is a worst-case scenario for any ICE car; That kind of use-case is where you really want an electric car!

I shudder to think what my diesel Yaris would do in such circumstances, and I'm averaging low-60's for my normal urban driving!

My dad once managed a shocking 130 miles on a single tank in his old Ford Focus TDCI doing that sort of driving - This is a car which normally, if driven the way it was designed for, can easily do over 500 miles on a tank!

Most cars need a good couple of miles before the engine reaches optimal operating temperature; Before that point they are really very inefficient so short journeys are really punishing. For short journeys, PHEV's and full electrics pretty much destroy everything else.

[TopIq]

Just done 500 miles in 3 days mostly on motorways/dual carridgeways and I was getting around 58-62 mpg. Not too bad I think considering I was sticking to around 65mph and wasn't on a 'Eco run'. (iQ 2 manual)

[dave hendy]

What sort of economy should you get from a 1.0 litre iQ cruising between 70-80 mph (my normal motorway speed)??

[Cyker]

's a good question... I imagine not too great as the engine will be working pretty hard at those speeds!

My Yaris D4D isn't too bad at 70mph (If I keep it constant it actually gets better mpg at that speed than 63mph with lorry overtaking!), and is running at ~2500rpm which is in the middle of the max-torque band.

Not sure what the IQ2's revving at at those speeds but given the torque difference I imagine it'd be a fair bit higher?

[dave hendy]

's a good question... I imagine not too great as the engine will be working pretty hard at those speeds!

My Yaris D4D isn't too bad at 70mph (If I keep it constant it actually gets better mpg at that speed than 63mph with lorry overtaking!), and is running at ~2500rpm which is in the middle of the max-torque band.

Not sure what the IQ2's revving at at those speeds but given the torque difference I imagine it'd be a fair bit higher?

It will be interesting to find out, I never get worse than 50 mpg from my Yaris and that's driving at above 70 mph shall we say!

[Grumpy Cabbie]

A 1.0 3 cyclinder city car with a top speed of 93 mph ain't going to be great at 80 is it?

Surprisingly, once the car is upto speed on the motorway it's quite smooth and bombs along nicely. Just don't expect any acceleration, more slowly gaining momentum. We managed about 48/50 mpg to London and back (200 miles each way) in our 1.0 auto.

But if you bought a small car to hammer on the motorway, then you'll be disappointed.

[dave hendy]

A 1.0 3 cyclinder city car with a top speed of 93 mph ain't going to be great at 80 is it?

Surprisingly, once the car is upto speed on the motorway it's quite smooth and bombs along nicely. Just don't expect any acceleration, more slowly gaining momentum. We managed about 48/50 mpg to London and back (200 miles each way) in our 1.0 auto.

But if you bought a small car to hammer on the motorway, then you'll be disappointed.

No cruising about 80 is fine which it did fine on the road test. Took a while to get there and you are stuffed if someone gets in your way!

[FROSTYBALLS]

In reality cruising at an indicated 80, will actually be around 75mph due to the speedometer being optimistic.

[iQ-Chris]

I agree, the iQ goes along quite nicely on the motorway. It's only uphill acceleration and a bit of road noise that lets it down slightly. But the car really wasn't designed for heavy motorway use :)

Chris

2012 iQ² with red leather upholstery ☆ upgraded interior lighting ☆ white backlit dashboard/switches ☆ auto-folding mirrors ☆ smart entry ☆ auto-locking doors ☆ chrome exhaust ☆

[TopIq]

I find the iq is pretty refined at speed. Engine and wind noise is well suppressed but the road noise varies massively according to the surface.

Some motorways/dual carridgeways are wonderfully quiet to drive on and I was impressed by the iq refinement on these roads yet some roads are just plain awful. The iq is still more refined than some larger cars I've driven though.

[AyeupIQ]

Don't know about anyone else but I always get better MPG from quality petrol rather than using cheap supermarket fuel. I try and use Shell when possible in both my IQ and Landcruiser Any comments most welcome.

[FROSTYBALLS]

Don't know about anyone else but I always get better MPG from quality petrol rather than using cheap supermarket fuel. I try and use Shell when possible in both my IQ and Landcruiser Any comments most welcome.

The use of branded vs supermarket fuels and premium vs standard has been debated several times on other forums. Some people find that using branded as opposed to supermarket fuels works well for them,and for others it makes no difference. Same with premium (BP Ultimate, etc) as opposed to supermarket or standard fuels.

[Cyker]

Yeah, that Toyota 3-pot VVTi is surprisingly smooth, even at higher RPMs (In fact it is smoother at high RPM than it is at idle ).

I remember being pleasantly surprised the first time I drove one as my only other experience with a 3-pot was a first gen VW Bluemotion Polo and that was apocalyptically bad (Diesel rattle plus lumpy 3-cylinder power delivery = Lots of dakka!)

That 3-pot VVTi can deffo hit the higher speeds okay (The number of Aygo/107/C1's flying past me on the motorway are a sign of that ), but obv. it will take longer to get there in the higher gears. If you're going to be doing motorway runs in a small car, the 1.3 VVTi and 1.4D4D are sooooo much more pleasant to drive.

I can't remember what the 1.3 was like now, but I do love how my Yaris will jump from 63 to 70 in two shakes of a tail which makes overtaking effortless; No need for downshifting, just floor it and let the turbo sing :D

The power delivery and gearing of the 1.4 D4D seems perfectly set up for this jump - 63 to 70 is slap bang in the middle of the max torque band (2000-3000rpm!) so the thing will just haul. I still get a joyous kick out of being able to do that after all this time :D

Especially compared to my first car, a 1.3 Fiesta, which basically required a 2 mile run-up to get from 60 to 70mph so you'd have to spot a gap waaaay behind you and try and time your acceleration to slip into it. Going from that PoS to mah Yaris was like stepping into a whole new world!

I still remember scaring the crap out of myself when I first drove it off the dealer's lot; Revved it far too hard (Classic petrol -> diesel mistake ) before engaging the clutch and the thing shot off the line like a scalded cat!

(Ironically, the 1.2 Fiesta had double the torque and horse-power of the 1.3 for some reason; I often wonder if I'd gotten that one instead, whether I'd have my diesel Yaris now...! )

[Hairy Nugget]

I'm getting 60mpg consistantly regardless of highway or city driving with my IQ2 manual, but to be honest I'm not that impressed as I used to average at 67mpg with a 2000 1.3 Yaris verso.

I think the 1.0 IQ with manual is geared waaaay to heavy, with only optimal fuel consumption under optimal conditions in mind.

You don't hit rev limiter in second before 68mph (110km/h), and is simply not able to get to it at all in forth.

Sit at 60mph with a Yaris verso 1.3 vs IQ 1.0 in 5th and floor it.. The Yaris will appear turbocharged in comparison despite barely any better power/weight ratio because it has a gearbox ratio that actually makes sense

[Zotja]

I have one question about mpg. 

Gallon is british gallon or us gallon? 

Uk4.5 us 3.8 Which one has in the iq? 

(Might be stupid questuon sorry)

[FROSTYBALLS]

I would imagine that IQ's sold outside the US, Canada, etc, would have the Imperial gallon (British), rather than the US gallon.

[jamski]

I'm getting around 42mpg at the moment. Was up to 45 in the summer. Generally I do a 12 mile town or country lane commute depending on the traffic, so either way it's not great for the fuel. I did start out with super unleaded and redex, but not convinced it did much at all, and now I've got the egr fix I see little point to either.