MX5 fuel consumption
Discussion
Hi everyone, noob here with a question - all advice gratefully received.
My 2007 Mazda MX5 1.8 has recently seen a marked deterioration in fuel consumption. I used to get 100 miles on the first 1/4 tank (according to the fuel gauge) and get to 300 miles before needing to fill up again, but recently I've been getting maybe 70 miles for the first 1/4 tank and well short of 300 for the whole tank.
I have checked tyre pressures and tracking - all fine.
Serviced not so long ago, clean bill of health and generally in very good nick with 58k miles on the clock.
I suspect there is fuel leaking out, but there is no smell of petrol and no puddle on the drive.
Can you suggest anything I should check before asking Mr Spanner to check the integrity of the fuel tank and fuel pump?
Thank you in anticipation....
My 2007 Mazda MX5 1.8 has recently seen a marked deterioration in fuel consumption. I used to get 100 miles on the first 1/4 tank (according to the fuel gauge) and get to 300 miles before needing to fill up again, but recently I've been getting maybe 70 miles for the first 1/4 tank and well short of 300 for the whole tank.
I have checked tyre pressures and tracking - all fine.
Serviced not so long ago, clean bill of health and generally in very good nick with 58k miles on the clock.
I suspect there is fuel leaking out, but there is no smell of petrol and no puddle on the drive.
Can you suggest anything I should check before asking Mr Spanner to check the integrity of the fuel tank and fuel pump?
Thank you in anticipation....
What was done on the recent service?
The suggestion of brakes is a good shout, I had a sticking caliper on my old civic and it took a good 10% or more out of the fuel economy. Oil grade can have a small impact - I did have a fill of semi-synthetic in that car, took off a couple MPG but nothing major, but it might be a source.
Have you calculated the acual fuel economy at all? Fill it to the brom, do your X number of miles (reset the trip when you fill), then fill it to the brim again. Divide miles driven by amount of fuel put in (if you divide it by litres, then the number you get will need multiplication by 4.546 to give the miles per gallon).
Is it possible your fuel gauge has an issue?
The suggestion of brakes is a good shout, I had a sticking caliper on my old civic and it took a good 10% or more out of the fuel economy. Oil grade can have a small impact - I did have a fill of semi-synthetic in that car, took off a couple MPG but nothing major, but it might be a source.
Have you calculated the acual fuel economy at all? Fill it to the brom, do your X number of miles (reset the trip when you fill), then fill it to the brim again. Divide miles driven by amount of fuel put in (if you divide it by litres, then the number you get will need multiplication by 4.546 to give the miles per gallon).
Is it possible your fuel gauge has an issue?
thatdude said:
What was done on the recent service?
The suggestion of brakes is a good shout, I had a sticking caliper on my old civic and it took a good 10% or more out of the fuel economy. Oil grade can have a small impact - I did have a fill of semi-synthetic in that car, took off a couple MPG but nothing major, but it might be a source.
Have you calculated the acual fuel economy at all? Fill it to the brom, do your X number of miles (reset the trip when you fill), then fill it to the brim again. Divide miles driven by amount of fuel put in (if you divide it by litres, then the number you get will need multiplication by 4.546 to give the miles per gallon).
Is it possible your fuel gauge has an issue?
Thank you everybody for your advice!The suggestion of brakes is a good shout, I had a sticking caliper on my old civic and it took a good 10% or more out of the fuel economy. Oil grade can have a small impact - I did have a fill of semi-synthetic in that car, took off a couple MPG but nothing major, but it might be a source.
Have you calculated the acual fuel economy at all? Fill it to the brom, do your X number of miles (reset the trip when you fill), then fill it to the brim again. Divide miles driven by amount of fuel put in (if you divide it by litres, then the number you get will need multiplication by 4.546 to give the miles per gallon).
Is it possible your fuel gauge has an issue?
I'm not aware of the brake sticking - no lurch when I coast to a gentle halt. Good shout though - I will check for extra heat...
Very possible the fuel gauge is on the blink but the odometer is going up by the right amount per tankful. I'll do some more specific sums and see what that tells me.
A cacky sensor is also possible - but a job for my friendly mechanic and not me! So I will check the brakes and my sums first of all.
No change to my driving habits nor unusual weather, soz I should have mentioned that in my OP.
Thank you!!!
Some mpg sums would be helpful. Our 2007 2.0 managed 38mpg on my 30 mile commute.
Sticky front caliper is a good shout as that's a familiar issue.
Changing gearbox and diff oil are service items every 25000 miles IIRC. I neglected those until 50000 miles and found the car smoother afterwards. Worth checking your own service record in case that's causing some 'drag'?
Sticky front caliper is a good shout as that's a familiar issue.
Changing gearbox and diff oil are service items every 25000 miles IIRC. I neglected those until 50000 miles and found the car smoother afterwards. Worth checking your own service record in case that's causing some 'drag'?
Wie schade said:
So whaddya know? When I got home from work last night on of the brake discs was warm. So that sticking caliper seems like a great call. I'll report back after it's been looked at and I have gone out for an Italian tune-up.
Thanks again everyone.
You do know that your discs would be warm if nothing was wrong, too?Thanks again everyone.
It's when it's significantly hotter, you have a sticky caliper.
You might already know this, so sorry if I'm teaching you to suck eggs.
If it is the caliper you'd know about it, the wheel itself will get very hot, and it's rare that two on the same axle stick at the same time so just compare the heat across the axles, it's when one is significantly hotter that you have an issue.
You may also hear metal pinging noises after a drive from the affected wheel and caliper if everything is really hot and has been dragging.
My mk2 mx5 suffered 5 or 6 siezed calipers in 6 years of ownership, they and other Japanese cars are somewhat notorious for it.
You may also hear metal pinging noises after a drive from the affected wheel and caliper if everything is really hot and has been dragging.
My mk2 mx5 suffered 5 or 6 siezed calipers in 6 years of ownership, they and other Japanese cars are somewhat notorious for it.
Due to COVID-19 it's only now that I have done any mileage at all after having the brakes looked at. I am delighted to report that the fuel economy is now back to where it used to be, so clearly it was the brakes that were the issue.
Grateful thanks to all who responded to my request!!!
Grateful thanks to all who responded to my request!!!
Wie schade said:
Due to COVID-19 it's only now that I have done any mileage at all after having the brakes looked at. I am delighted to report that the fuel economy is now back to where it used to be, so clearly it was the brakes that were the issue.
Grateful thanks to all who responded to my request!!!
Excellent stuff, thanks for coming back to update the thread!Grateful thanks to all who responded to my request!!!
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