261 miles at 17.8 gallons

[TXCumtrensh]

I think it may be time for a SERIOUS tune up for the Q

Just filled up 17.8 gallons, and only had 261 miles on the Q, didnt use the AC, nor the heater..

143,000 miles

Im sure the O2 sensors are probably still OE, and sparkplugs im unsure of..

Kinda depressing

thats like.. 14 mpg

[redtop91]

How do you drive? LOL the VH45DE is a beast.

[CrimsonQ]

I get 14-18 with mine. Heavy foot i guess.

thats why i have the rusty accord for driving thats not 4 fun

[Rex]

FYI guys he's driving a 98, that has a VH41DE.

Low MPG's is usually due to spark/burn issues.

Check anything regarding spark burn - 02's, KS's, plugs, air filter, fuel rail, etc.

[qship96]

boy you guys shure do jump the gun thinking throwing parts at it will make a difference without first inquiring how those 261 miles were driven.If they were all city or short trip 5-10 mile runs to and from a to b,then 14mpg is reasonable.If we are talking a long,highway trip thats another---not enough info here to diagnose if he even has a problem.

[TXCumtrensh]

Yeah, its typically 10 mile trips to work and back.. I know the VH41DE sucks down some serious gas.

[elwesso]

14 MPG is decent to good on a Q for 10 mile trips (even without proper adequate idling to warm the car) where most speeds of 60 are not maintained for most of that...

Everytime a new member comes on and they think their MPG sucks its because they ask too mcuh of the car. You cant weigh 4000lbs (or whatever), have a V8, and a bunch of luxury features, and sip on fuel. You have to lose somewhere!

NEVER consider Q45 city mileage. If you can go out on an extended highway trip and get 20ish MPG, your Q is doing just fine.

[Jesda]

Expect a mild improvement after replacing the plugs.

14 is par for the VH45 Q, but unusually low for VH41.

[elwesso]

Expect a mild improvement after replacing the plugs.

14 is par for the VH45 Q, but unusually low for VH41.

I will let some Y33 guys chime in but I dont think 14 in a pure city environment is too far off track.

[92Q45guy]

I think it may be time for a SERIOUS tune up for the Q

Just filled up 17.8 gallons, and only had 261 miles on the Q, didnt use the AC, nor the heater..

143,000 miles

Im sure the O2 sensors are probably still OE, and sparkplugs im unsure of..

Kinda depressing

thats like.. 14 mpg

How would the heater affect your MPG?

[xerexabante]

my f50 doing about 17.4-18.4mpg city.

[greenwar]

My 99 Q gets 15-17 in City and around 22-23 in highway (depending on wind and speed/accelaration) using non-oxygeneted gasoline(only fuel used). I religiously check tire pressure).

[TXCumtrensh]

How would the heater affect your MPG?

if im not mistaken, doesnt the AC compressor kick on to help the condenser get hot, to warm up the radiator faster? I may be wrong, but the AC/Heater is still another accessory.

I do pretty much all city driving.. 15 miles to work, 15 home.. everyday, thats about it

[elwesso]

if im not mistaken, doesnt the AC compressor kick on to help the condenser get hot, to warm up the radiator faster? I may be wrong, but the AC/Heater is still another accessory.

I do pretty much all city driving.. 15 miles to work, 15 home.. everyday, thats about it

No that certainly doesnt happen. However that effect sorta happens because anytime the climate thingy is on AUTO the compressor will come on....

[92Q45guy]

True, with the auto button the A/C compressor does turn on.

[StarPD]

Traffic conditions, terrain, and driving styles can all affect mileage.Accelerating a 4,000+ car to 30 or 40 MPH, especially repeatedly can drastically reduce fuel economy. So can varying terrain, like rises and hills.

F50s with instant and average fuel mileage displays can reveal just how severe stop and go traffic and hilly conditions can drop those numbers. I have one in my 2005 Q45, and it's quite interesting. Driving at a steady speed slowly raises mileage, but it doesn't take much stop and go to drop it.

I try to avoid surface streets and rush hour traffic whenever possible. So far, in mixed city and freeway driving, I've been averaging arond 19-20 MPG, but I don't floor it every time I take off, and coast a little approaching red lights and stop signs since I'm going to have to stop anyway. But when I'm forced to drive in heavy traffic, I can see my mileage drop and stay down.

With all engine components in good tune, mileage steady-state should be pretty good considering the HP and weight of a Q, but accelerating in 1st and second gear wil necessarily drop it.

BMW recommends accelerating fairly quickly to get the car up into the higher gears, then cruising with a light throttle to hold it there to get best fuel economy.

Here's a suggestion you may want to try: Top off your tank, then take a 100 mile trip on freeways or open road where there's little traffic. Keep A/C compressor off and windows closed. Fuel up and top off again. Check your mileage. If it's 20 to 23 MPG, your driving conditions are responsible for low mileage. If less than that, you have a problem with engine tune, air filter, plugs, injectors,or a defective/improper component like knock sensor, O2 sensor, etc.

My '94 Q45t was admittedly unusual, but on a 7200 mile trip through 19 States 3 years ago, I averaged 25.5 MPG for the entire trip. I took almost no Interstates except where I had to, but rather all two lane US highways, going through every small town along the way. I spent 10 days local driving around Chicago, then 4 more days local driving in Northern Michigan. The trip was from Phoenix up through Utah, Wyoming, and Montana, across through the Dakotas, down through Iowa and into Wisconsin. Then around Chicago up into Michigan. Finallly, down to Florida then across the Gulf, through Texas and NM, and back home to Phoenix. I burned NO measurable amount of oil. Estimating by my gas gauge and trip odo, at times I was pulling 28 to 30 MPG at 65 MPH! I was absolutely amazed, and of course, had a grin that stretched my face out of shape.

To what do I attribute this performance? Good break-in, even though the car had 27k on it when I bought it. Soon after getting it, I was very sick but had to make a trip from Phoenix to LA for a funeral. My brother flew out from Chicago and drove us in my car to LA on Interstate 10. He held over 135 to 140 indicated all the way there and back. No, we never got stopped. Fuel mileage was around 14 mpg. But after we got back, I noticed a considerable increase in mileage and power. From then on, it ran like a champ and gave unusuallly good fuel mileage.

Now my new to me 2005 Q45 had 24k on it when I bought it. A woman drove it. Fuel mileage was holding around 16 mpg. I took it on a few relatively short trips, holding around 75 MPH, and doing some spirited (WOT) 100 MPH passing on steep upgrades and winding it up through the gears. Fuel mileage is now around 19 MPG combined freeway and surface street driving. I use M1 5 w 30 oil and Chevron premium (oxygenated) gas. New air filter, trans flush, and diff drain and refill with synthetic gear oil.

If everything on your car checks out good, I suggest trying to re-break it in. My experience is that a Q CAN be broken in even after the engine parts have been seated in if it wasn't done properly the first time, although it may take a while. Find a safe place and repeatedy red-line it through the gears, then drive it very fast for a while, safely of course, and with known good tires properly inflated and all fluids up and in good condition. Then do another fuel mileage check. Just be VERY, VERY careful. Crashing or getting busted is not a good way to achieve good performance and mileage, and will certainly ruin your day.