O Dogg

I just got my mass air sensor replaced and I'm hoping this will improve my fuel economy. I filled up today and want to gauge my 2001 ML430's fuel economy against the status quo. What are you getting out of your ML's? Thanks.

GDawgC220

Last time I had the ML for a week, I had to refill twice in the same week. I'm figuring about 250-300 miles / tank. I guess the big V8 really likes to gulp gas.

kaze81

My 2002 ML320 has approx 17 mpg for highway driving. It has 7K miles on the clock (1/28/04).

Hope this info will help

KZ

O Dogg

This sucks...I replaced the air sensor and the unthinkable has happened...my fuel economy has gotten worse. I am on pace to get about 100 miles out of my tank. Previously, I'd gotten 120. I'm really starting to hate this vehicle.

GDawgC220

WHAT!?! 120 miles / tank??? That is not normal at all...at a minimum, even with heavy acceleration from my 430, i get atleast 200 - 250 / tank and that thing sux gas.

Have you tried replacing your air filter? that can regain some gas mileage or even O2 sensors wearing out has an effect on that...if it's still in warranty, i'd go talk to your dealer about it.

EDIT: Have you had your fuel sender replaced? That was a common thing on the ML's as well, the fuel gauge was not correct. When I filled up, it would not go to the top at all, sometimes at the first quarter mark when topped off...that maybe an issue.

O Dogg

GDawg,

We share the same sentiments. I called my local dealer and they told me not to use the unscientific method of following the gas gauge. If I did, I'd be at a half tank and about 87 miles driven. I was told to do the following:

1. Run this tank out.
2. Fill up until auto shut off.
3. Drive until ready to refuel.
4. Go to same pump and refill again until auto shut off. Log exact amount of fuel dispensed.
5. Drive again until ready to refuel. Go to same pump and fill to auto shut off. Log exact amount of fuel dispensed.
6. Using the two logged entries, figure out fuel economy.

7. Also, the service manager was pretty confident that the overhead fuel economy computation was fairly accurate. If this is the case, I'm rolling along at 11 mpg.


I'll let you guys know the results of my study...at this rate I shouldn't have to wait long to refuel.

GDawgC220

Yep...gas mileage in the 430 really does sux. Filled up yesterday morning, did errands around town, drove into boston this morning (about 22 miles) and 1/4 of the tank is apprently gone already. Most of the time, the overhead thing is correct.

I may try that method next time I run this tank down. Thanks for the tip

pointman

im pissed about the fuel economy of the mls too... my 320 gets 180...my 55 gets 160.

boltonblue

The very worst milage I've ever gotten was 15 which puts me at needing a fill at about 265.
The very best i've ever gotten was 24.
that was in the summer from toronto to buffalo to mass on the turnpike with cruise control set at 80 with almost no traffic. I think I touched the brakes twice.

O Dogg

I'm still getting this pathetic gas mileage...I'm still running the fuel out of this tank so I can do an accurate calculation. However, as the needle approaches the 3/4 mark, I only have about 35 miles out of this tank. Also, I filled up at Chevron this weekend, and I am still getting a little hesitation when the engine is cold.

O Dogg

Okay, I guess it is time for brainstorming. What do you guys think could be potential sources for my fuel economy/hesitation problems. Since I replaced the Air Flow Sensor, I haven't noticed a big difference, except for the CEL being off. Actually, the hesitation didn't even start until I replaced it.

I am not much of a mechanic, obviously, but I think the sensor I had replaced is different than the O2 sensor, correct? Could the O2 sensor be the source of my current problems? What about a standard tune-up with plugs, air filter, etc.?

Any other ideas are welcome. I have an aftermarket warranty, so hopefully anything that needs to be corrected will be covered. Unfortunately, my local dealership won't take it, so I have to use an independent shop for my repairs.

pointman

i think it is normal, i have the same issues.

O Dogg

ah-

Do you have the same issue with hesitaion when the engine is cold, as well? this shouldn't be considered "normal," should it?

pointman

can you be more detailed on hesitation? cause it does take long for throttle response when cold.

O Dogg

When I drive when the engine is cold, I feel a "gap" in acceleration for a second...usually somewhere around 3000 rpm. I guess the best way to express this would be the feeling you might expect if fuel wasn't being distributed properly for a split second and caused acceleration to hiccup. Essentially, there is a brief moment when I'm not "going."

pointman

sounds normal. 320 right?

O Dogg

430, actually. And all I can hope is that I am not communicating this problem efficiently to you. Because if this is considered normal, then a lot of ML's on the road have a serious safety issue right now. I've owned some nice cars and I've owned some crappy cars, and I can't even remember any of the crappy ones having a problem similar to this.

m500

My 03 ML500 with 45% local 55% highway drive is average in high 16 mpg. I usually fill is up when it lite up and its aways in between the range of 280 to 320 depends how much local Driving I done and how hard I drive. I think I'm doing better then most of the V8 SUV/truck out there for now.

O Dogg

Well, if I could just get 12-14mpg and smooth acceleration out of this thing, I'd probably be happy.

O Dogg

Well, I did my calculation today and based on the mileage indicated by my trip meter and the amount of fuel deposited before the auto-stop kicked in, I am getting 11.1 mpg in the city. How does this compare with the rest of you? I am still getting the cold engine hesitation, but at least the mpg wasn't as bad as I predicted. Still not stellar, but I'll try a fuel additive to clean the injectors, etc. and see how that fares. Any recommendations as to additives?

russell

If the overhead display is accurate enough. Then I got 18 mpg from 90% local and 10% highway. I never tried to really calculated the fuel efficiency. I have 02 ML500 with 12000 miles.

mihir_d

I have a 00 320 and had to get my CATS replaced at 71K miles...its been a month now since they did the CATS and my mileage has dropped from 16-29 mpg to 11-14 mpg...and am experiencing the same kind of hesitation at about 3000 rpm as is being discussed in this thread.

Never had this drop in mileage problem or hesitation problem before it went to the shop for the CAT replacement...

I think there is something wrong with the vehicle since it got its exhaust re-worked...

The MB shop though is unable to explain why this happened...

O Dogg

Sorry for my ignorance, but what is the CATS?

mihir_d

Form a critical component of any vehicle's exhaust system...

Here's a link that might help..
http://auto.howstuffworks.com/catalytic-converter.htm

O Dogg

Oh, I didn't realize that CATS was the acronym for catalytic converter. I should've been able to deduce that.