Mpg is250

[ahmedali44]

Today went Woking on m25 stuck to 60mph for 30 mins was getting nearly 47mpg was really surprised then 80mph dropped down to 43mpg still surprised. If I stuck to 60 all the way would get maybe more. For a v6 good mpg.but couldn't drive 60 miles at 60mph. At 80 still getting just over 40 mph.was really happy with mpg

[is200 Newbie]

Non drivers of these done realise how good the mpg is on them 

[Linas.P]

Yes that sounds about right - it is very efficient engine. You can get up to 40MPG, up to 90MPH... I have never seen 47... but that is because I never drive at 60. I often drive Romford to Luton and getting ~42MPG depending on the traffic. I am sure this is related to the way engine is well-paired with 6 speed auto gearbox and gear rations which allows low RPM at high speeds.

[Ishaq]

For the MPG what should I follow the Average Tank MPG or the range as both seem different. The Average Tank seems to show a higher MPG.

 

I get around 27-29 driving around London, so really happy with that.

[bobmc]

Last week I used 52.8 ltrs over 368.5 miles, mostly on a trip to manchester and back and I used cruise for a lot of the motorway sections at just under 70mph

That works out to an average of 31.72 MPG which is pretty much in line with what the car was displaying. The highest I saw over the whole journey was 37 MPG

 

 

[steveledzep]

8 minutes ago, bobmc said:

Last week I used 52.8 ltrs over 368.5 miles, mostly on a trip to manchester and back and I used cruise for a lot of the motorway sections at just under 70mph

That works out to an average of 31.72 MPG which is pretty much in line with what the car was displaying. The highest I saw over the whole journey was 37 MPG

 

 

That's pretty much what I get too.  Highest reading I've seen on the Tank Average is 38 and that was going east on the M4 with cruise at 70mph.

Think my convertible is heavier than the saloon, so I'm pleased with that.

[Linas.P]

I usually check my Tank AVG against my "real consumption". What I found is that Tank AVG is showing me slightly lower MPG than the real one. Which sound to be too good to be true, but I have  assumption why is that - I usually get well in to "reserve" and it looks like computer thinks that my car have already run out of fuel and doesn't count last 10-20 miles (which are driven on reserve) very accurately.

I check real consumption by filling full tank until it starts clicking (I found the most I could get were ~63.72l) and then drive until it shows 0 + 10/20 on reserve depending on the road. Then I fill full tank again and divide the recent miles on the new tank fill which in theory should be 100% accurate consumption... unless it leaks.

So the readings over last 20k miles are ~ 27.8 which is based on like 30/70 Extra Urban/Urban - I can easily get 40+ on steady motorways speeds. Few month ago went to Bath (from London) and it was showing ~44MPG@~75MPH.

[bobmc]

I'm sure someone will correct me if this is 'urban myth' but I have been told it's not good for the engine to run too low into  fuel reserves.

The reasoning being that any contaminants will be at the bottom of the tank and so you may end up feeding 'dirty' fuel into the engine.

 

[Linas.P]

I think that is correct (at least I believe in it), especially if you never run on reserve and one day after 200k miles go and do it right till the car stops... But because I do it every refill... I expect my tank "not to have any dirty fuel". To be honest I almost deliberately do that exactly to prevent the problem of some "stuff" accumulating on the bottom of the tank.

I might be doing it wrong, but so far did ~80k miles in 3 different Lexus IS250 and always been doing it without any issues.

[bobmc]

You may have a point Linas (how do you do that thing where the you get the forum handle show up? - nevermind..) but most of us are buying cars that have a few miles on them already so we don't know how the previous owners have been refueling their cars. So it's still a risk to take. I don't make a habit of driving with a full tank because you are carrying extra weight and cost but I don't like to see the fuel warning light come on.

 

 

[bobmc]

You may have a point Linas (how do you do that thing where you get the forum handle to show up? - nevermind..) but most of us are buying cars that have a few miles on them already so we don't know how the previous owners have been refueling their cars. So it's still a risk to take. I don't make a habit of driving with a full tank because you are carrying extra weight and cost but I don't like to see the fuel warning light come on.

 

 

[bobmc]

double post - sorry!
 

 

 

[Cracksta]

I thought running the car fuel low (because of dirty fuel) was a myth or possible true 50 years ago?

I would imagine the tank is positioned so every last drop goes down a feed pipe to the engine, so it doesn't matter if the fuel is full, mid or empty? I usually refuel when the yellow light comes on and when I do, i get about 55 litres (theres still 10 litres in there for reserve)

[bobmc]

I'm no expert but it doesn't look like it from the exploded parts diagram, all the hoses are on the upper side as is the fuel pump.

 

[Linas.P]

29 minutes ago, bobmc said:

I'm no expert but it doesn't look like it from the exploded parts diagram, all the hoses are on the upper side as is the fuel pump.

Fuel pump is indeed at the top of the tank as is all electronics, fuel level sensors etc. But there is fuel suction tube (77168-52020) running from the pump to the bottom of the tank.