I been checking my mpg last 2 days ? LOOK - Page 2 - PeachParts Mercedes-Benz Forum

partsman225 · #16 10-26-2011, 06:21 PM

The pn#.on my 83 300d.with.the.3.07's reads 123 542 18 52
On my 85.300d with the.2.88's reads..... ....... 123 542 27 57
And on my old 82 240d with the 3.69's reads 123 542 89 01

Can anyonw verify this for me.? It pn is.visible at the bottom od the speedo head.
thanks

partsman225 · #17 10-26-2011, 06:28 PM

Btw i couldnt do mympg today cause i only had a half gallon of fuel which it took all of it.
Herea.my log.of today though.i think it would have taking another half gal at most but dont know
overall avg 33.2mph
movin avg 40.0 mph
max.speed 64.mph
total time 54.05 mins
movin time 42.57 mins
stopped time.11.45 mins

Jetmugg · #18 10-26-2011, 10:00 PM

Your test method is not good. That may seem harsh, but it's true. As other posters have said, you need to burn at least 1 full tankful of fuel before trying to make any mpg measurements. Fill it all the way to the filler neck, drive until the tank is very low, then refill and calculate. Repeat over several tankfuls to get a meaningful average.

ngarover · #19 10-27-2011, 01:42 PM

Quote:

Originally Posted by Hip001

I would be skeptical when ANY of you say your w123 300d Automatic gets 30mpg+ !(unless you are hypermiling, windows up, 45mpg, no AC, no stops, curves, or hills)
BUT with that said if you are AND have registered multi tanks and verified with GPS then I wanna know your secret!!!

NEVER did ANY of my w123 300d's get into the 30's!

I've hit 31mpg with my 4-spd 240d's commute to work. Top speed 50mph & no AC. Then the next week 24mpg 70mph AC blowing high.

Just checked it again... 31.5 this time. The AC belts cut off right now, but other than that, everything else is running. Best I ever saw with my 81 was 28.3 and best with my 85 CD was 25.5 I know the IP might not be perfectly timed on the 85CD, but it starts on the first crank, and seeing the mpg I'm hesitant to mess with it any more. I have been now driving this car as my every day car and have a total of 3k on the new engine.

Ryan Z · #20 10-28-2011, 08:52 AM

My experience with the '84 SD is that there must be a way for a big air bubble to form in the tank. The other week I filled it to the neck, drove a little, and filled it to the neck again. Fine. Then drove for a few days and filled up again. Took over 2 gallons more than it should have. I'm giving up on acurate milage checks.
Last year I had it filled and ran out at 350 miles.

Hip001 · #21 10-28-2011, 09:02 AM

Quote:

Originally Posted by ngarover

Just checked it again... 31.5 this time. The AC belts cut off right now, but other than that, everything else is running. Best I ever saw with my 81 was 28.3 and best with my 85 CD was 25.5 I know the IP might not be perfectly timed on the 85CD, but it starts on the first crank, and seeing the mpg I'm hesitant to mess with it any more. I have been now driving this car as my every day car and have a total of 3k on the new engine.

Is this car the 300d? is it manual shift? I'd still be skeptical and wonder if your speedo is accurate. If you are truely getting 30mpg then congrats, you have a RARE car!! (& I'm gonna start looking for a motor to rebuild like yours!!) I'm sure no AC helps too but not a option here in central Florida.

boneheaddoctor · #22 10-28-2011, 09:51 AM

Quote:

Originally Posted by Hip001

Is this car the 300d? is it manual shift? I'd still be skeptical and wonder if your speedo is accurate. If you are truely getting 30mpg then congrats, you have a RARE car!! (& I'm gonna start looking for a motor to rebuild like yours!!) I'm sure no AC helps too but not a option here in central Florida.

A lot depends on exactly what those miles are, how its driven and where.

Flat open highway you can get great mileage if there are no mountains or frequent stops.

I average 26mpm on a city highway loop between my house and office, and have for years (1983 300D, automatic). I can and have gotten 31-32 mpg on long FLAT open 100% highway trips averaging between 65 and 80 mph with the cruise control engaged, the last one being between Washington DC and Bizmark North Dakota and back this summer (done in 2 days each way). But I certainly never get that driving over the appalacian mountatins between here and Pittsburgh on a different route or local driving. (GPS verified)

BTW, my W116 is only 1-2 mpg lower than my W123 on the same routes.

ngarover · #23 10-28-2011, 10:11 AM

Quote:

Originally Posted by Hip001

Is this car the 300d? is it manual shift? I'd still be skeptical and wonder if your speedo is accurate. If you are truely getting 30mpg then congrats, you have a RARE car!! (& I'm gonna start looking for a motor to rebuild like yours!!) I'm sure no AC helps too but not a option here in central Florida.

Just to know, I cut the A/C belt AFTER getting over 31.. My alternator belts needed to be changed after I got to our farm, so the first 500 miles of the trip had it on. The compressor is starting to make noise, so I'm looking at replacing it later and figured I would just save myself the time of having to undo it to get the belt off.

The trip was from N GA. to Indiana, taking 75... So plenty of mountains to cover. My daily drives are pretty flat, 11 miles each way with lots of stop and go in town to drop kids off.

I verified my speedo etc with my GPS, it's right on the money. First MB I've had where they where actually accurate.

I use the method of filling the tank fully, running it down and refuel to the top again, so I know the gallons used and the milage. Might not get me down to the decimal point, but averaged out over multiple tanks it's it's more accurate than some of the claims I see coming from car ads.

Along with the engine being new, the transmission is also running new fluid etc. I did a quick timing of the IP using the bubble up method, so it's not exact, but has the car running great. My tires are also brand new and aired correctly.

The mpg it's getting makes me not want to make any changes for fear that It will go down again.

Yesterdays fill up, the tank showing 1/4 tank, and the odometer and gps showing 448 miles traveled on that tank. it took 14.2 gallons to fill it up. That's 31.5 mpg.

ngarover · #24 10-28-2011, 10:15 AM

Quote:

Originally Posted by boneheaddoctor

A lot depends on exactly what those miles are, how its driven and where.

Flat open highway you can get great mileage if there are no mountains or frequent stops.

I average 26mpm on a city highway loop between my house and office, and have for years (1983 300D, automatic). I can and have gotten 31-32 mpg on long FLAT open 100% highway trips averaging between 65 and 80 mph with the cruise control engaged, the last one being between Washington DC and Bizmark North Dakota and back this summer (done in 2 days each way). But I certainly never get that driving over the appalacian mountatins between here and Pittsburgh on a different route or local driving. (GPS verified)

BTW, my W116 is only 1-2 mpg lower than my W123 on the same routes.

Lived in Bismarck for years.

boneheaddoctor · #25 10-28-2011, 10:58 AM

Quote:

Originally Posted by ngarover

Lived in Bismarck for years.

Actually was two towns west visiting a long time friend. Bismark had some rather heavy flooding along the Mighty Mo when I was there. Got pictures of it.

Hip001 · #26 10-28-2011, 11:04 AM

Quote:

Originally Posted by ngarover

The mpg it's getting makes me not want to make any changes for fear that It will go down again.

Yesterdays fill up, the tank showing 1/4 tank, and the odometer and gps showing 448 miles traveled on that tank. it took 14.2 gallons to fill it up. That's 31.5 mpg.

Bravo Ngarover! You have accomplished what I and many others could not!! Honestly if my 1st 300d would of got 30mpg I would of kept it! The "fill-up to fill-up miles/Gal to fill the tank for multi tanks" is the only way to calculate mpg in my opinion and even better if the fill-ups are at the same station and time. I inquired MULTI times how to improve my 1985 300d's mpg to my mechanic and he tried all the tune up things with 26mpg being the peak for me. I'm wondering if Injection pump pressure to each cylinder & timing are the key to this riddle, Along with new injector nozzles? I did the pop test and got all the same. I've not replaced nozzles in the Benz but it made a HUGE difference on my VW TDI(43mpg went up to 47mpg in it)!!
I had a little brake drag on my 240d so while repairing the front suspension I replaced the front and rear calipers, rubber brake lines, rotors and pads. my 1st normal tank since then and i'm over 300 miles in just over 1/2 tank. keeping my fingers crossed that this will get in the low to mid 30's.

partsman225 · #27 10-29-2011, 11:50 AM

Yes a got deisel in a one gallon jugs.

I did this same thing with my 91 560sel i was burning 2.5 gals on my same route to and from.work which is 28.5 miles total comes.to 12.5 mpg...amd thats roght on what ibeen getting.my mpgs range from 12.2 to 12.6 mpg. With most times getting 12.54 on the money
and i only get 17.5 all highway at 75to80mph.

So i thought this way to would.get me in the ball park with the.300d

Would this be.a.better.way then ?
.say i take.the.feed &return lines off stick my gallon jug under the hood woth both hoses in it run the.car.to get hoses purged out refill the jug to the 1gallon mark..then drive to work and back...would this.be.a.better.way? I know i can make.it home.and that much