High fuel consumption

[Arsalane]

Hi,

I just bought a second hand estate avensis 1.8 valvmetric model. Its a 2009 and less than 50k on thr clock. I tried to measure the fuel consumption and Igot the fuel warning light at 360 miles which means it s using approximatey low 30s MPG mostly on motorway.this is far off thr 40 and above consumption for regular avensiss. What could be wrong here ?

[alan333]

Begin with the easy things - is the air filter old/choked, and when were the spark plugs last changed.

My 2012 1.8 auto could get as low as low to mid 30's if driven fast on motorways, normal driving gave about 40, nun-like driving gave about 50.

[Arsalane]

Serviced everything very recently. I got about 30mpg mostly driving on the motorway at speeds no more than 70mph

[Byzii]

The very simple method of resetting everything would be to disconnect the negative terminal of the Battery for ~10 minutes.

Then, once connected back, start the car with all accessories turned off and leave it idling for around 5 minutes, then take it on a nice long drive, or even better would be a drive consisting of mixed driving, such as a bit of city driving, a bit of motorway.

I think around the 300-400 mile mark the car should start feeling normal again since it takes a while for the ECU to learn everything again and then you can check the mpg then. If it's still bad then I guess you would need to connect the car to a diagnostic computer to really see what's going on, you really don't want to start changing things willy nilly.

Off the top of my head, the spark plugs could be due for a replacement, then the usual air filter, then my guess would be to check the Mass Air Sensor.

Last thing is oil. There have been numerous threads on here saying that when car is filled with incorrect oil (for example, if your engine takes 0W-20 but shop puts in 5W-30) then the extra drag on the engine could very well bring those mpgs way down.

If this is the case then simply changing the oil would help but I would be very suspicios of something like this. Sure, the oil could've been changed just before selling and previous owner didn't get to see the change, but it could be that the previous owner tried masking an issue with the engine by using a thicker oil which isn't unheard of.

[FROSTYBALLS]

Moved to the Avensis club.

[Konrad C]

Make sure the tyre pressures are at least 34 psi form  the fronts. I have mine at 35 -36 psi. My car is the tourer version. '58 plate 2009. My car was showing 37 mpg with a mixture of outer London driving/local journeys. Range shows 420 miles, but it goes up and down depending on driving conditions.  

I accidentally blew the OBD fuse whilst trying one of the fixes to the EPB. The car ran terrible and idle was very low. That fuse is located in the fuse box under the glovebox. Once the fuse was replaced, the car relearned everything. The EPB fault was caused by me using the wrong diagnostic device, to reset the EPB by deleting the calibrations. In the end I got Techstream to clear the cautions, fixing the EPB. Talking of brakes, make sure they are not binding.     

[Heidfirst]

On 1/12/2019 at 3:06 AM, Arsalane said:

I just bought a second hand estate avensis 1.8 valvmetric model. Its a 2009 and less than 50k on thr clock. I tried to measure the fuel consumption and Igot the fuel warning light at 360 miles which means it s using approximatey low 30s MPG mostly on motorway.

The low fuel warning light will come on with ~10l still in the tank so yes, ~33mpg assuming that it was full to start with (but you really should do brim to brim top up).

Tbh that is only slightly less than I have been getting in winter with my usage ( quite a high % of urban, often barely warming up) .  Is yours a manual or CVT, saloon or estate?

As already mentioned check tyres - not only pressures but what size/type they are (e.g. I am now on my winter tyres so don't expect the same fuel economy as on my summers) & that no brakes are binding. Lots of little things add up.

[Mihanicos]

Check the charcoal canister according to the manufacturer's specifications. A common problem with them is the leakage of one of the three ports. it is a plastic lid with a port and this lid is glued to the rest of the canister. A sponge with glue is used which eventually fails. It can be removed easily and glued with a better glue for plastics. The canister is on the passenger side of the engine bay, just behind the headlights assembly.

A hose is connected to this port from the throttle body housing which is under engine vacuum, thereby drawing air into the engine. Because the Mass air flow sensor  is located just after the air filter, this extra air drawn into the engine is not measured.

The result is a lean air to fuel mixture with the adverse effects on engine life, overheating in the combustion chambers, pre ignition and poor fuel economy.

 

Regards,

 

Chris.

Edited January 13, 2019 by Mihanicos

[Mr Wolf]

This morning I returned from a trip to Warwick travelling on the M40, M25 and A roads. The outward journey was last Friday morning and total miles travelled to and back was 284 miles. The outward journey took just over 3 hours and coming back was 2 hours 35 minutes. I never knowingly exceeded the speed limit but as the traffic was light I kept to about 70 mph most of the journey, particularly on today's return journey. The mpg was shown as 50.2 for the combined journeys. I always use Shell Super Power which is supposed to give better MPG and probably does by about 3 or 4 MPG. In recent times, after filling up range shows 461 miles.

[Arsalane]

Hi ,

Thank you all for these suggestions, Ill check them all and will let you know. 

The car is a manual estate with 16-17 inch rims. I think my fuel tank is 47 liters up to the point which the fuel warning light come up. Using this reference I checked the mpg only over mostly motorway driving at 70 mph using 20 liters of tesco fuel this time and I got 179 miles or 40 mpg which is quite better. I refilled the tank once more and will check the usage again using tesco fuel.  

If any help, the car has one more issue too. That is after 30 minute of driving, when coming to halt or slowing down , placing the car into netural the car idles high momenterly above 2k before falling back below 1k. Down shifting helps a bit 

[Colourd]

Tesco's Fuel ? there's your problem 😞 avoid supermarket fuels

[Catlover]

27 minutes ago, Colourd said:

Tesco's Fuel ? there's your problem 😞 avoid supermarket fuels

Tesco fuel the problem? Seeing as the original post was quoting 30mpg, then the most recent post stated 40mpg using Tesco fuel, that implies Tesco fuel is doing ok.  A friend of mine was a tanker driver supplying fuel to petrol stations and he says supermarket fuel deliveries were the same as he delivered elsewhere.

[TonyHSD]

Hi, yes all useful information members has already mentioned, referring Tesco fuel I can said that recently been better than Shell and as good as BP and Texaco garages. I usually experience poor fuel consumption and poor engine performance From Morrison’s and Sainsbury’s fuels, my local Tesco and Asda are doing just well. 

[Konrad C]

In the last few days since I filled the car I have done around 309+ miles, and showing 100 miles remaining. This is from a mixture of driving conditions. 

The fuel consumption is showing over 37 mpg.

1.8 Vmatic manual, estate. 

[Arsalane]

30 mpg was on super cheap Costco fuel

[Konrad C]

I last filled up with Sainsbury's fuel. Before that Morrison's. There are as much supermarkets fuel stations as standalone. 

[Konrad C]

7 hours ago, Arsalane said:

30 mpg was on super cheap Costco fuel

That is better than some friends car Mercedes A Class 1.6 petrol turbo, '68 plate, a 2/3 year old Fiesta 1.0L Ecoboost both mid 20's mpg, and Mercedes B Class 2010 petrol 30 mpg. All these cars are smaller, with smaller engines, yet are returning worst fuel consumption! These are real world figures from real world conditions. 
 

[Catlover]

9 hours ago, Arsalane said:

30 mpg was on super cheap Costco fuel

From a reliable source I have heard Costco fuel is good quality. And they do 95 and 99 octane.  The other week I filled up at Costco and it was 111.9 per litre, whereas my local Shell station was 121.9, thats 10p per litre, or 45p per gallon......... that 9 shillings in old money, thats some saving...... and my Prius runs just fine on it.

 Here is a copy/paste from the Costco fuel web site - Q and A

Deposit control additives: 
Every grade of Kirkland Signature™ Fuel contains deposit control additive that keeps your engine protected and running like new. 
Variations in deposit control additive formulations are the main difference between brands of fuel. Kirkland Signature™ Fuels have been proven to clean deposits and restore dirty engine components to like-new performance.

Station Maintenance:
Good station operation and maintenance means the fuel is filtered and that contaminants, such as sediment and water, do not find their way into our members' vehicles. Costco fuel stations are well-maintained by our capable attendants so you may be confident that the fuel going into your car is clean.

Costco uses fuel filters in the petrol pumps to catch particles or debris larger than 10 microns in diameter. For comparison, the average human hair is seventy microns thick.

Costco uses ethanol-compatible filters designed to catch sediment, water, or phase-separated ethanol and water mixtures.

Costco's electronic sensors continuously monitor our underground storage tanks for water. END