BAD Fuel or what?

[JOHNBMWM5]

Just filled the car back up after seeing the fuel gauge going down quicker than normal.
Driving the car easy this last two weeks with 25 mile runs on easy open roads to and from the golf club.
MPG dropped to 19MPG from 25 MPG
I remember filling up with TESCO 99 in a Garage I don't usually use, any ideas as to this sudden drop in MPG. Car seems to run OK.
Weather here very good.

[Neil McRae]

its the computer finally working out what was in using properly. 19 sounds good to me!

[JOHNBMWM5]

Originally Posted by Neil McRae

its the computer finally working out what was in using properly. 19 sounds good to me!

Yea but I have been brimming it, so I know just what it has used, this is a mystery to me, if I was pushing I would expect it but on the roads I have been using in the last two weeks all duel carriageways it should be higher.

[mcvaughan]

Yes, 19 is good. I'm getting 17.

[M54ccibo]

19? Man, haven't seen that, well, ever. Sitting at 14.3 right now

[Neil McRae]

14.3 you should get a trophy for that I'm at 20 but in the run-in period. the old car went back at 11 LOL

[JOHNBMWM5]

Originally Posted by mcvaughan

Yes, 19 is good. I'm getting 17.

UK gallons are bigger = 1.2 US

[itsme123]

what is your average speed as it is shown on your idrive?

[mstmng]

driving central only:
13-14 UK (imperial) mpg
combined: rises to 18-20

[M54ccibo]

Originally Posted by Neil McRae

14.3 you should get a trophy for that I'm at 20 but in the run-in period. the old car went back at 11 LOL

I like the right pedal

If the oldie was an E60 M5, you'll see 14's too...I was always 10 or 11 with the old beast.

[mcvaughan]

Originally Posted by M54ccibo

I like the right pedal

If the oldie was an E60 M5, you'll see 14's too...I was always 10 or 11 with the old beast.

LOL I was usually around 12.5 in my E60.

[mcvaughan]

Originally Posted by johnbmw6

UK gallons are bigger = 1.2 US

Ahhhh, true.

[JOHNBMWM5]

Originally Posted by itsme123

what is your average speed as it is shown on your idrive?

58MPH

[Dionysus]

Best I could do on Shell Nitro+ was 35.4mpg (UK) or an indicative 640 miles max range, so nowhere near the claimed 37.2mpg extra urban. I was consistently exceeding the claimed extra urban by 6mp in the 535d with similar driving (63mpg actual vs. 56.5mpg claimed) when running on Shell Nitro+ Diesel. Perhaps the S63TU is very sensitive to fuel?

I would guess it's fuel quality related, but may also be somewhat temperature related as we have had a drop of a few degrees recently. I have started to notice that the ride is harsher on cold tyres on mine since the break-in service and the change in the weather.

I'm going to try some BP Ultimate (I believe SimonH mentioned an mpg improvement with BP in a previous thread) just out of curiosity.

When I had my X5 serviced after 2 years/16000 miles, the overall max mpg dropped by 3mpg (the idrive was indicating the oil was overfilled after the service, however, the service department put this down to a faulty sensor). It dropped by another 2mpg after the tyres were changed at 25000 miles, but recovered back to the post service level after they had been run in. I did mention the drop in overall mpg to the service dept, only to be told that it was more likely that my driving style had changed with familiarity, even though most of my driving in on motorways with the cruise control set. It is easy to be dismissive of such issues when there is no easy answer.

On a lighter note, I must say that I am finding the M5 pretty boring to drive for economy. Reminds me of the comments in this video (2:29 onwards) : -

[JOHNBMWM5]

Originally Posted by Dionysus

Best I could do on Shell Nitro+ was 35.4mpg (UK) or an indicative 640 miles max range, so nowhere near the claimed 37.2mpg extra urban. I was consistently exceeding the claimed extra urban by 6mp in the 535d with similar driving (63mpg actual vs. 56.5mpg claimed) when running on Shell Nitro+ Diesel. Perhaps the S63TU is very sensitive to fuel?

I would guess it's fuel quality related, but may also be somewhat temperature related as we have had a drop of a few degrees recently. I have started to notice that the ride is harsher on cold tyres on mine since the break-in service and the change in the weather.

I'm going to try some BP Ultimate (I believe SimonH mentioned an mpg improvement with BP in a previous thread) just out of curiosity.

When I had my X5 serviced after 2 years/16000 miles, the overall max mpg dropped by 3mpg (the idrive was indicating the oil was overfilled after the service, however, the service department put this down to a faulty sensor). It dropped by another 2mpg after the tyres were changed at 25000 miles, but recovered back to the post service level after they had been run in. I did mention the drop in overall mpg to the service dept, only to be told that it was more likely that my driving style had changed with familiarity, even though most of my driving in on motorways with the cruise control set. It is easy to be dismissive of such issues when there is no easy answer.

On a lighter note, I must say that I am finding the M5 pretty boring to drive for economy. Reminds me of the comments in this video (2:29 onwards) : -

Many thanks for you impute, I have noticed this considerable drop on a "regular commute" which when home do tree times a week and nothing else in between , it stands out dropping 6 MPG and the weather here is consistent and warm at the moment.
Coopers BMW say it would be fuel related if it goes away in the next week or two after topping up with none supermarket fuel.
So They say wait an see, then book it in if required, can't be farer than that.
I must admit I have never seen more than 26 MPG since taking ownership even "Looking to economy drive".