Hi,
Just bought a '02 320 with SE. Got a full tank of gas with it. Just getting familiar with the car. The mileage that I am getting is ~17mpg on mostly freeway. Only driven it 5 times (74 miles). I've used almost 1/4 tank so for the 20 gal tank that is about 5 gallons and that puts me at 14.8 mpg! I pulled the air filter last night and vaccumed it (too late to buy one). I pumped up the tires to the recommended 28/32(f/r). This morning I still got the usual 17 mpg! I get 18 on my V8 mustang and 18 on my ML430 on the same trip(driven more agressively). Tonight, I will fill up the gas again and check to see if the gauge is accurate.
Does anyone know how the amount of gas is calculated? I am thinking that it is just from the pulse signal duration that the computer sends to the fuel injector. The distance checks out with my other cars. I am thinking or resetting the computer so it can relearn my driving habits. Maybe all the test driving has taught the computer to be in 'power' mode? Or is the calculation just not accurate? Maybe the dealer filled it with regular or not all the way? Or the previous owner used regular and the computer hasn't learned to use premium yet?
The car had a service B (46K miles now)just before I bought it. It did sit in the lot for 1-2 months.
Other than this mileage issue, I am ecstatic over the car.
Thanks for your help.
Art

 

We have the same car.

I would reset all the computers and give it a few tanks before I hit the panic button. Which one on the menu are you looking at? There's one that is from the start of the engine and another one that has to be reset. Not the one from engine start, but the other one, hadn't been reset for about 8000 miles when we got the car and I reset it.

Always hand calculate it when figuring gas mileage. I always put 91 octane in it out here in AZ. By only putting 74 miles on it really doesn't give a clear picture of how you drive it and what the mpg will be. Drive it for a few tanks with your normal driving style and routings and then see.

Congrats.

Toby

 

I filled in 3.2 gallons. So this works out to 23.1mpg. I understand that the error decreases with volume of gas filled. Then I reset both computers. The 'after reset' computer mileage doesn't match the 'after start' computer #s. It's not a big deal, just a curiosity. Does anybody know the algorithm and sensors used to used to calculate mileage for both 'computers'?

 

My computer is pretty accurate (with about 1 to 1.5 mpg). I've checked it a few different times.

On the "c" 320... my milage is only around 17 in the city and 27 @ 70 mph on the highway. the 'ML"320 was 17 in the city and 24 straight highway...

With that being said, the 320 is not too good on fuel consumption.

Also, i see you have a '91 stang, which puts out what.... 220hp... is much lighter than your 215 hp "E320". Also is the stang a 5 speed? autos get worse milage by nature. The ML430.... i would think the 320 would get better than that but never can tell, espcially cause the ML iis a V8 with AWD, heavier, and less aerodynamic.

 

The Mustang is a 5 speed V8. 'Slightly' modified. Fun to drive(Sleeper look, surprised many cars!). So my mods and sometimes heavy foot compensate for the weight savings and the stick. Also, single overhead cam so don't expect fuel economy for this older tech.

The ML430's mileage seems to track the computer. No 'trip' computer, just 'instant' mileage and since reset mileage.

The E320 seems to 'have trouble' with the Since Start Computer. When I start the engine the MPG is ~6 and takes a long time to 'average' up. The Since Reset Computer seems to be working OK and giving me OK V6 mileage. I am just wondering if the Since Start Computer 'problem' is unique to me or an algorithm issue.

 

My '96 E320 gives 20-22 mpg around town and 28-32 mpg on highway. I don't drive hard on my car, maybe that's why. On highway I drive 65-72 mph

 

I just filled up and the computer registered 23.6 for 308 miles while I calculated 22.7. Not too bad considering that most of this is in town driving. I too start at 9 - 11 mpg when cold and the start up and warm up does take some time to average out.

Jim

 

I got 21 mpg on avg. Got my ECU chipped, which boot gas mileage about 1mpg w/ normal driving (SoCal horrible traffic).

The problem, even since I got it chipped & new air intake, I rarely drive normal. Slamming on the accelerator is so much fun, I keep doing it. Of course, gas mileage take a hit.

So for weekend driving (no stop&go traffic): 20 mpg +
Weekday driving (stop&go): 22 mpg +

Sound like a hybrid huh: better gas mileage w/ stop&go traffic. With $3.20/gal, fill up twice a week, it's a hit.

Our W211 get 22mpg too. I don't know how can people get 27-28mpg.

 

Easy. I also live in Southern California (Los Angeles), and commute to San Diego on a regular basis. I resist the temptation to punch the gas in my E320. I've gotten really good at using the cruise control...I think I use the cruise control knob more than the gas pedal! I even use it in some 'stop-and-go' situations. I only cruise, avoid 'stop-and-go' traffic as much as possible, and never go above 70 MPH on the freeway. When I do 'highway-only' driving (with minimal pedal-punching), I get about 27.5-30.9 MPG. In 'stop-and-go' conditions, mileage drops dramatically.