Poor MPG - Temporarily

[YarisHybrid2016]

Hi,

I know this has been discussed before, but last week when it was fairly warm (around +24 C), I could not better about 50 MPG (instantaneous), combined with the car clearly requiring more power to hold speed vs. what is usually observed (the power needle was clearly >1 tick mark higher for certain sections of road for extended periods).

I had just refueled, and so I wondered if the car was still metering the fuel for the last tank and so a bit screwed up?

It seems OK again now, driving as expected, but this seemed quite strange. I checked the brakes weren't dragging, that I hadn't had a tyre lose pressure, or that I hadn't switched the heater on accidentally. Driving with the AC/blower OFF made no difference, and combined with the fact it was consistently poor with the higher reported power reading, I was starting to think something was wrong.

In total, this persisted over 2 journeys of about 15 miles each, on good A road that is traveled often. Weather was good (dry, light wind).

The car was serviced just a couple of days ago, and no faults were reported, so... ??????   I couldn't find any external factors that could have caused it.

(I appreciate this may be a bit of a non-problem, but still intriguing!)

Are hybrids known to do any kind of HV Battery conditioning at certain times? Immediately prior to these journeys, the HV Battery was low (3 bars) before the car had been sat for about a week, and had been observed not accepting charge during driving (i.e. not above 4 bars) prior to this where it would have been expected (braking downhill which usually results in 6-7 bars).

[Anthony Poli]

Hi,

I did see somebody commenting on Battery conditioning the other day. I think that was on a 07 Prius with 100,000 miles or so. Do you use cruise control?

For me it helps, while on boring roads with no big hills.

[YarisHybrid2016]

Hi,

Whilst I have it I tend to only use it on the motorway. It is quite aggressive at maintaining speed and even on fairly small hills (undulations to be more exact) it is on/off the throttle more than it needs to be.

Went out again today (24 miles) and it seems fine. I'll report back if it does it again.

[Anthony Poli]

Strange, on my way back from holiday abroad. Cruise control at 70 with shopping and roof box, my 2010 Auris hybrid still managed a reasonable 56mpg.

Do you keep the car in Eco?

Switching Eco off could be the reason for poorer mpg.

Sent from my iPhone using Tapatalk

[YarisHybrid2016]

Yes, car was in Eco. Speed was around 55 MPH, and I usually see about 75 MPG reported (instantaneous). It wouldn't better about 50 MPG.

What usually happens is from cold, I get anything from between 35-50 MPG during warm-up, then about 10 minutes into a journey the MPG rises noticably as it leaves warm-up into normal running. It was like it never left warm-up. It was less willing to enter EV mode, too (e.g. during braking) especially later in the drive when it would normally enter EV mode below 45 MPH during braking. Instead, it kept the ICE running and entered EV later.

[Anthony Poli]

9 hours ago, YarisHybrid2016 said:

Yes, car was in Eco. Speed was around 55 MPH, and I usually see about 75 MPG reported (instantaneous). It wouldn't better about 50 MPG.

What usually happens is from cold, I get anything from between 35-50 MPG during warm-up, then about 10 minutes into a journey the MPG rises noticably as it leaves warm-up into normal running. It was like it never left warm-up. It was less willing to enter EV mode, too (e.g. during braking) especially later in the drive when it would normally enter EV mode below 45 MPH during braking. Instead, it kept the ICE running and entered EV later.

I'm Sorry, I didn't spot you were talking about the instantaneous figures. I mainly concentrate on the Average figure on the dashboard itself and how many miles clocked up by each fill up.

I have started using Fuelly.com , so I am able to compare both cars. The Yaris does return better than the Auris.

[YarisHybrid2016]

It was just for two trips I noticed this behavior. Seems fine again now.

[kithmo]

Just a glitch in the Matrix 

[YarisHybrid2016]

I guess so! 

[vanilla.coffee]

Mine did exactly this. 

Found the Dyson Hoover type filter blocked for the HV Battery cooling motor under the rear seat. 

Cleaned the filter, Battery obviously now running cooler and the symptoms you described are now gone :-)

[YarisHybrid2016]

I need to check mine - haven't looked at it yet. Thanks for the reminder!