Gas Mileage Issues on my 04 X5 4.4L

[Wayne's World]

Are you comparing your numbers on snow tires versus all season or summer? Snow or Winter tires get significantly worse gas mileage than all seasons or summer tires. This could be the difference you're seeing.

Also - fuel system cleaners arent all created equal. Check out BG 44K @ bgprod.com. Even Techron cant come close. And it WILL help with your MPG - you don't have to go on blind faith that it's actually doing something in there.

Edit - if you're using Sunoco to get the 94, chances are, the gas is blended with Ethanol. I don't know of any Sunoco that doesn't blend. This will result in a 20% hit in your MPG. And if I recall correctly, pretty much every station in GTA blends. You'll have to do some digging to find a 'brand' station that doesn't. In the states, I was lucky enough to find a Shell that doesn't blend about 8mins from home.

[m5james]

Originally Posted by Greekthang

I was thinking that the O2 sensors maybe the culprit as well. Maybe I should attack those first and go from there

After 100k miles, it couldn't hurt to change them anyways. I was able to get mine from Autozone for like $70 each, so it's not a bad idea for something that could help in the long run anyways.

[Greekthang]

Originally Posted by Wayne's World

Are you comparing your numbers on snow tires versus all season or summer? Snow or Winter tires get significantly worse gas mileage than all seasons or summer tires. This could be the difference you're seeing.

Also - fuel system cleaners arent all created equal. Check out BG 44K @ bgprod.com. Even Techron cant come close. And it WILL help with your MPG - you don't have to go on blind faith that it's actually doing something in there.

Edit - if you're using Sunoco to get the 94, chances are, the gas is blended with Ethanol. I don't know of any Sunoco that doesn't blend. This will result in a 20% hit in your MPG. And if I recall correctly, pretty much every station in GTA blends. You'll have to do some digging to find a 'brand' station that doesn't. In the states, I was lucky enough to find a Shell that doesn't blend about 8mins from home.

Never thought of the tire thing I actually forgot about that. Ill see what blends we have here but that was never the issue before however could me increasing the octane to 94 insteady of 91 cause any gas issues ??

[m5james]

Ehh, I doubt going from 91 to 94 could cause worse gas mileage. The computer will burn it all, but after a certain point, higher octane on a stock compression or non-forced induction becomes pointless after a while since the stock ECU doesn't really know what to do w/ it. Higher octane, anything in the high 90's to low 100's are more for boosted and high compression engines in order to keep it cool. I'd imagine you've got plenty of cool in Canada, so 91 should be fine. With the summers here in Las Boise, I wish I could get my hands on something higher than 91-92 and w/o ethanol, without have to pay over $5 a gallon for it

[Greekthang]

Well then its going back down to a steady diet of 91. There is only a few pennies difference up here with 91-94 so I figure why not. I gotta find a non ethenol place up here and I dont even know where to start

[BigGar]

I realize that there are knock sensors and all manner of electronic tuning going on inside that ECU, but in my experience with high performance motorcycles, I want to run the lowest octane that doesn't ping or detonate. I wouldn't run lower than recommended by BMW of course but running a 94 octane fuel would not be necessary. Running lower than recommended will likely not hurt anything as the ECU will sense it and adjust, possibly lowering overall performance.


Gar

[phil47]

Originally Posted by Greekthang

Well then its going back down to a steady diet of 91. There is only a few pennies difference up here with 91-94 so I figure why not. I gotta find a non ethenol place up here and I dont even know where to start

Around here, the only way to get 94 AKI Octane is with the ethanol-blended gasolines. I certainly get worse fuel economy when I use the ethanol blends.

[Greekthang]

Originally Posted by Greekthang

So guys here is the dilemma,

As soon as my X5 hit the 100,000km mark it started giving crappy gas mileage. I gauge this because when I use to fill my

tank completely to the top keeping the same driving habits the first quarter tank (at the 3/4 mark) would yield me 200km

where as now it only yields me 170km.

I recently did an Inspection 2 and still nothing. I added a fuel cleaner to clean out the fuel system and still nothing.

Just recently changed an ignition coil that was misfiring still nothing.

Just wondering if there is anyone else with the same issues. I am running 94 octane.

Would the ignition coils need a changing maybe ?

Im at a loss here people

Thanks

Well People here is a great piece of news. I switched to Shell 91 V-Power this tank full and with the exact same driving habits at the exact same 3/4 mark yielded me an extra 33km and this is with snow tires on. So basically what my gas mileage was when I had all seasons I am now doing again with the winters on. To me that’s proof enough to stick with Shell. Damn Sunoco and there Ethenol additive crap.

[Wayne's World]

awesome!

Ethanol-blend was the dumbest idea. Sure it brings your overall cost down a bit (not much) but then you take a hit in MPG so you're probably spending more.

[Greekthang]

Originally Posted by Wayne's World

awesome!

Ethanol-blend was the dumbest idea. Sure it brings your overall cost down a bit (not much) but then you take a hit in MPG so you're probably spending more.

Yup !! I am sticking with Shell from now on