LS460 2008 Huge fuel consumption

[lucas192]

Hi,

I bought my ls 2 weeks ago and I notice I have huge fuel consumption. I do mostly city driving 7 miles one way and back. When I drive normal under speed limits and without crazy accelerations I get only 12mpg. I try for last 2 days drive extremely smooth and slow with minimal gas usage and everywhere I can with cruise control ON and I only get 15-16mpg but is nearly impossible and unsafe to driving like that all the time. I read a forum members mpg reports for ls460 and average for normal city driving is 18-20mpg. I check my air filters and they are clean , also I do not have any fault codes on the dash. Can anyone let me know if my mpg is normal or if not point me where I should to look for problems to sort it out fuel economy. Regards Lucas

[ColinBarber]

I think you should get better than what you are getting. Check the temperature of the wheels after a journey, you may have a brake that is sticking.

[lucas192]

Will do that today when I come back from work. Car is very low mileage , only 23000mls.

[Malc]

I think firstly look to see who did the last full service and when ( if it's quite recent ), and ask them maybe ..............  for a 9 year old car to have only done 23k miles seems quite extraordinary .........  is there an odd tale to tell about how you acquired this car ............ and it's history ?   That may throw some light on your terrible fuel returns 

Malc

[lucas192]

Car was bought from a dealer ,it has only one owner from new , last service done by a dealer from I bought a car. 

[Malc]

Lexus main dealer ?  or a car sales general dealer ?  who may not have a clue about the specifics of servicing the Ls 460 

If it's the Lexus or Toyota Main Dealer then I would take it straight back to them to get the car " fit for purpose "  ( under their implied warranty legally sold with the car )  or if it wasn't them then maybe bite the bullet and take it to the Lexus main dealer for a full 10 year service

Presumably you have done all the appropriate checks to ensure the mileage and pre ownership data you have is quite correct and honest ?

Malc

 

[lucas192]

it was sales general dealer(Grays of Chatham). Everything I check looks legit. Also condition of the car tells it not done many miles. 

[lucas192]

Just check wheel temp after normal driving and all are cold...only disc brakes are hot. 

[dendonc]

20 hours ago, Malc said:

or if it wasn't them then maybe bite the bullet and take it to the Lexus main dealer for a full 10 year service

Expensive yes, but, cheaper in the long term & made much cheaper by 'peace of mind' value, what price the latter otherwise?

[dendonc]

22 hours ago, lucas192 said:

minimal gas usage

Are you LPG? if so they do less MPG

[Cotswold Pete]

Just thought, but in past when I have had cars that do short city miles the throttle gets clogged up quicker and so fuel intake is all over the place.

Is your rev counter up and down while stationary, might indicate cleaning throttle worth a look.

[lucas192]

Rev at idle is fine...everything with engine sounds ok without any obvious sympthoms. 

[doro708]

Take it for a longer run and see what you get then . Reset the trip computer , do a 50 mile journey on the motorway with the cruise at 70-80 and see what you get . At least like this you can compare both fuel consumption and see if you have any problem . 

[lucas192]

Just come back from 70 mile journey on the motorway (cruise set 70-75) and only get 23mpg. 

[NemesisUK]

From the EU spec sheet, you could just be seeing normal variation, plus your driving style may be impacting consumption?

Fuel consumption	simulation based on the European type of traffic
(mileage)	extra-urban / city / highway / average combined:

 

l/100km:	9.1-10.9 / 16.4-19.7 / 8.8-10.6 / 13
mpg (imp.):	25.9-31 / 14.3-17.2 / 26.7-32.1 / 21.8
mpg (U.S.):	21.5-25.8 / 11.9-14.3 / 22.2-26.7 / 18.1
km/l:	9.2-11 / 5.1-6.1 / 9.5-11.4 / 7.7

[dendonc]

1 hour ago, lucas192 said:

(cruise set 70-75) and only get 23mpg.

If you want to check the max economy mpg keep it to 56mph for as many of the miles traveled you can, it might be of anecdotal  interest anyway.

[steve2006]

Do these cars "adapt" to the driving style of the driver?

My theory suggests that the previous owner may have driven the car let's say in a sporty fashion, the ECU then adopts this mode.

You as a new owner drive in a more sedate fashion so the car needs time to adjust, you could always have the engine ECU reset to default mode and then see if the MPG improves based on your driving style.

Another thing to have checked is if the engine is reaching its fully warmed up state.

[NemesisUK]

Adaptions usually are related with the transmission ECU, certainly wrt Mercedes. The TCM will adapt to one's driving style, adjusting shift points to be more efficient..

 

[lucas192]

How can I reset ECU?

[NemesisUK]

You would need access to Techstream, so a dealership or well equipped (and knowledgeable) independent. 

But I don't think that's your problem. In fact I don't think you  have a problem, going by the consumption figures table above.

[Dale_V]

what you are seeing/getting is normal

 

12mpg is about right for city driving and 23mpg is about right for a combined drive.

 

Your ls460 isnt broke

[doro708]

It can't be normal as the guys in US are getting 18/19 mpg city driving and 30 mpg at 80mpg and 33 mpg at 70mph where fuel is worse and the gallon is smaller to. 

According to what i have seen on the US forum and also applicable to any car the factors that can impact the economy are : 

1) Oil , better economy with 0W-30 vs 5W-30

2) Air filter

3) Tyre pressure 

4) Fuel quality , try some Shell V Power on a longer run 

 

Also on Fuelly , your car seem to get better mileage : http://www.fuelly.com/car/lexus/ls460

Pictures attached are from US forum .

[Cotswold Pete]

19 hours ago, lucas192 said:

Just come back from 70 mile journey on the motorway (cruise set 70-75) and only get 23mpg. 

Assuming you set the system as soon as you hit the motorway, and assuming it is you average bit of London motorway, I would have expected at least 30mpg, if not 33mpg.

My LS400 at 56mph does about 38mpg, and even got 39mpg once on M5 on Somerset Levels. At 80mph fully loaded (passengers & boot) - does 30-31mpg

I would think any adaptive response in the ECU is not going to account for these figures of 23mpg.  I get 28mpg on way to work (All A roads with small amount of town driving), and that includes a climb of 500foot as soon as I leave the house, and the old beast is not warmed up and chewing though about a gallon every 5 miles on the climb.

I have never found tyre pressure to make that much difference (other than wearing out the tyre), though I did find a small improvement (and I mean small) after engine oil change and full ATF change.

I have tried Shell V-Power a few times and noticed no difference, other than to wallet.

 

Is it worth you giving the guys at Japex (Kings Langley) a call, seem to be well regarded in sorting out what is going on.

[lexus707]

Not trying to teach a granny how to suck eggs, but are you driving it in sports mode?

[Dale_V]

6 hours ago, doro708 said:

It can't be normal as the guys in US are getting 18/19 mpg city driving and 30 mpg at 80mpg and 33 mpg at 70mph where fuel is worse and the gallon is smaller to.

According to what i have seen on the US forum and also applicable to any car the factors that can impact the economy are :

1) Oil , better economy with 0W-30 vs 5W-30

2) Air filter

3) Tyre pressure

4) Fuel quality , try some Shell V Power on a longer run

 

Also on Fuelly , your car seem to get better mileage : http://www.fuelly.com/car/lexus/ls460

Pictures attached are from US forum .

Im not even trying to be funny here, but its a 4.6L petrol car that weights ALOT, you live in london, theres not a hope in hell you're going to get anywhere near 20mpg driving continuously in the city. 23Mpg is about right for a TOUCH of city driving and then the majority of motorway (depending on how much motorway you do, that figure will rise)

 

The best ive seen was 31mpg and that was after doing about 300miles of 70mph cruising on the way to germany. and my LS460 definitly ISNT broke.