1999 300D Fuel Milage Question - Page 2 - PeachParts Mercedes-Benz Forum

hobbitss · #16 02-15-2008, 01:52 PM

Quote:

Originally Posted by nhdoc

I must admit I never knew you could monitor fuel economy through the OBDII port on our cars...that's great information. Is there more than one model of ScanGuageII? I see it goes for about $170...if it does all it says it does that is not too bad.

It comes in handy... I found that as soon as I installed it on my older car my gas mileage improved just from being more aware of it... Someone suggested I set one of the gauges to display the Throttle Position and that helped me be more consistent which improved economy more.... It also keeps data on fuel usage, engine water temps, air intake temps, RPM, MPH, etc...
I am currently monitoring RPM, MPH, Throttle Position and MPG in the Gauge mode... I also keep a yearly Excel spread sheet of my actual mileage and fuel usage...
My 98 E300D does 68mph at 2500rpm and 81-82mph at 3000rpm with a warmed up engine water temp of 173F...

Jack525 · #17 02-20-2008, 07:22 PM

Hobbitss

Iv'e actually been using the Scangauge I for almost 2 years now with my 99 300D. With Scanguage I, several settings affect the MPG result, including the TANK FILL gallons when you fill the tank. Don't know if Scangauge II works the same way.

Jack525

nhdoc · #18 02-20-2008, 10:08 PM

I ordered a scangauge II the other day...should be here tomorrow and I will install it before a trip to NJ Saturday...it will be interesting to see how accurate it is for me.

hobbitss · #19 02-20-2008, 11:49 PM

Quote:

Originally Posted by Jack525

Hobbitss

Iv'e actually been using the Scangauge I for almost 2 years now with my 99 300D. With Scanguage I, several settings affect the MPG result, including the TANK FILL gallons when you fill the tank. Don't know if Scangauge II works the same way.

Jack525

Yes it does... Mine has been pretty close from the start so I haven't bothered to make the adjustments, but I plan to do so now that I've transfered it to the new car...
First tank full finished at 26.78mpg including driving in 2 snow storms... On the commutes without storms the ScangaugeII showed 27.5 to 28.5... Looking forward to the summer mileage...

Joe

hobbitss · #20 02-20-2008, 11:53 PM

Quote:

Originally Posted by nhdoc

I ordered a scangauge II the other day...should be here tomorrow and I will install it before a trip to NJ Saturday...it will be interesting to see how accurate it is for me.

I believe the latest ScangaugeII has more gauges programed into it than mine... I can get mine upgraded but I haven't been willing to part with it yet...

I'd like to see the boost level on mine if possible...

nhdoc · #21 02-25-2008, 08:33 AM

Quote:

Originally Posted by hobbitss

I believe the latest ScangaugeII has more gauges programed into it than mine... I can get mine upgraded but I haven't been willing to part with it yet...

I'd like to see the boost level on mine if possible...

I got one last week and have had some fun playing with it. I can monitor boost, not directly but by choosing MAP which is manifold absolute pressure...in other words you need to subtract atmospheric pressure from it to get actual boost. 1 ATM is about 14.9 PSI which is what it will display normally at idle. I see on mine it will peak at about 30.4 PSI which is about 15.5 PSI of boost...that must be the cutoff for the '98 I am guessing.

I also found it useful monitoring instant MPGs driving 500+ miles on the trip I took yesterday. I could see that if I set the cruise to hold at say 70MPH and the car was climbing a hill that the MPGs would dip quite a bit to the high teens to maintain the speed (depending on the grade, of course), but if I overrode the cruise and tried to maximize the MPGs I could hold the speed within a couple of MPHs and boost the efficiency to the mid to high 20's while climbing hills. I landed up being able to get about 32 MPG on the RT including about 70 miles around town which is pretty good for winter fuel. I've rarely broken 30 under the same conditions in winter.

raMBow · #22 02-25-2008, 08:55 AM

With the ScangaugeII, I am presuming from what I saw that it only gives the code, not the "explanation" for the code and I would have to decipher?

Is that correct?

But for the price I could print out a code list and handle that.

Oh, and where have you all mounted your unit? any pictures?

nhdoc · #23 02-25-2008, 09:11 AM

Quote:

Originally Posted by raMBow

With the ScangaugeII, I am presuming from what I saw that it only gives the code, not the "explanation" for the code and I would have to decipher?

Is that correct?

But for the price I could print out a code list and handle that.

Oh, and where have you all mounted your unit? any pictures?

I have not experienced a code with mine but usually all these scanners do is present the code, ie P0403. You can easily get a chart with the standard OBD codes to decipher them though.

Right now mine is temporarily stuck on the small area above the steering wheel under the instrument cluster's odometer area. It will not interfere with the telescoping wheel function as long as it sits on the little shelf above the part which moves but there is not as much depth there as needed to secure it with the velcro they supply so I will get something better to hold it more securely since I don't plan on moving it from car to car I don't need velcro. I will probably just get some good "stickum" pad to hold the bottom and back and it will stay there fine. Then I will pull the bottom panel and shove the wire behind it for a more professional look than it now has with the wire dangling.

anghrist · #24 02-27-2008, 02:35 AM

I've been keeping an eye on my mileage for the past year and a half. Typically my trip computer will read 28-32 MPG. Yesterday and today I''ve been at 34.5 and 35.3 and I've been having fuel issues. What gives?? Not that I'm complaining.

hobbitss · #25 02-27-2008, 11:03 AM

Quote:

Originally Posted by nhdoc

I got one last week and have had some fun playing with it. I can monitor boost, not directly but by choosing MAP which is manifold absolute pressure...in other words you need to subtract atmospheric pressure from it to get actual boost. 1 ATM is about 14.9 PSI which is what it will display normally at idle. I see on mine it will peak at about 30.4 PSI which is about 15.5 PSI of boost...that must be the cutoff for the '98 I am guessing.

I also found it useful monitoring instant MPGs driving 500+ miles on the trip I took yesterday. I could see that if I set the cruise to hold at say 70MPH and the car was climbing a hill that the MPGs would dip quite a bit to the high teens to maintain the speed (depending on the grade, of course), but if I overrode the cruise and tried to maximize the MPGs I could hold the speed within a couple of MPHs and boost the efficiency to the mid to high 20's while climbing hills. I landed up being able to get about 32 MPG on the RT including about 70 miles around town which is pretty good for winter fuel. I've rarely broken 30 under the same conditions in winter.

I've observed the same fluctuations in mileage depending on grade and wind conditions but haven't had the car long enough to be able to adjust my driving style much... I have dropped my cruising speed from the usual 75 to 70 and have noticed that level road fuel efficiency between 40 and 50mph can be amazing...