Quirky mileage problem, 1980 240D - PeachParts Mercedes-Benz Forum

nickofoxford · #1 05-01-2009, 08:13 PM

So this is "fill up" weekend for me, and I went to check the last two tanks mileage..

What I found was I had gotten 510 miles between TWO tanks in my 1980 240D. I usually just want a roundabout mileage to watch if anything is on the spaz, so I just use 17 gallons as the tank capacity. I will run the car until it is on reserve and fill it up to the neck at the same pump.

Anyway 510 miles divided by (17 gallons X 2) comes out to be 15 miles per gallon. Here comes the fun part. After doing my calculation today and not resetting the trip odometer, it was dead at 510 the whole ~12 miles to and home from school today.

So my mileage could be better.. -shew-

What a great way to start off my rainy weekend, I've learned to HATE taking the dash out of the 240D. It's not even pulling it out it's trying to get the speedometer cable off

What should I do about this?

t walgamuth · #2 05-01-2009, 09:38 PM

Have you checked your odo against the mile markers on the interstate lately? I bet its slipping.

charmalu · #3 05-01-2009, 09:47 PM

When I pull out the instrument cluster, I remove the cable from the transmission. this gives the slack to get your hand behind it the cluster.

works for me.

Charlie

leathermang · #4 05-01-2009, 10:33 PM

I do not think I can get 17 gallons into my 240.... are you sure about that number ?
Maybe I have a critter in mine taking up space...

t walgamuth · #5 05-02-2009, 06:43 AM

Oh well, after re reading it upon Greg's post I see that the op is just rouning his fuel amounts.

To check the mileage you have to simply fill the tank, drive it until its low and refill it. Keep your mileage while driving and look at the gallons you put in to fill it. Divide the gallons into the miles and you have miles per gallon.

Estimating either quantity will result in worth less calculations.

Greg is right you will be hard pressed to get a 240 tank empty enough to take 17 gallons.

Shawn T. W. · #6 05-02-2009, 09:29 AM

Quote:

Originally Posted by t walgamuth

Oh well, after re reading it upon Greg's post I see that the op is just rouning his fuel amounts.

To check the mileage you have to simply fill the tank, drive it until its low and refill it. Keep your mileage while driving and look at the gallons you put in to fill it. Divide the gallons into the miles and you have miles per gallon.

Estimating either quantity will result in worth less calculations.

Greg is right you will be hard pressed to get a 240 tank empty enough to take 17 gallons.

Yeah the pump where you fill it will give you the gallons, even if you fill from your own supply (wvo) go to a pump, and see how much you put in . . .

nickofoxford · #7 05-02-2009, 12:27 PM

Im going to give a shot at a multi-post reply, hopefully this will work

Quote:

Originally Posted by t walgamuth

Have you checked your odo against the mile markers on the interstate lately? I bet its slipping.

I did a couple weeks ago out of curiosity, but I reset the trip odometer first and it was counting along perfectly. Could it be slipping as the miles add up? I think that may be the problem

Quote:

Originally Posted by charmalu

When I pull out the instrument cluster, I remove the cable from the transmission. this gives the slack to get your hand behind it the cluster.

works for me.

Charlie

I never thought to do that, how hard is it to get the cable off the transmission? I have this neat cable greasing machine I've wanted to use on the odometer cable for a while.

Quote:

Originally Posted by leathermang

I do not think I can get 17 gallons into my 240.... are you sure about that number ?
Maybe I have a critter in mine taking up space...

lmfao that reminds me about the baby squirrel in my intake when I got the 240D... it's a possibility

I really should check my manual for the right number. I use 17 just to get a roundabout number, I like to keep a log to get a heads up on how she's burning.

Quote:

Originally Posted by t walgamuth

Oh well, after re reading it upon Greg's post I see that the op is just rouning his fuel amounts.

To check the mileage you have to simply fill the tank, drive it until its low and refill it. Keep your mileage while driving and look at the gallons you put in to fill it. Divide the gallons into the miles and you have miles per gallon.

Estimating either quantity will result in worth less calculations.

Greg is right you will be hard pressed to get a 240 tank empty enough to take 17 gallons.

Correct, I just get an estimate. My mileage calculations have never been high I just wanted to watch consumption to know when to change filters.

Im going to start a new log book and find a pump around here with a non-vandalized gallon readout

nickofoxford · #8 05-02-2009, 12:29 PM

Quote:

Originally Posted by Shawn T. W.

Yeah the pump where you fill it will give you the gallons, even if you fill from your own supply (wvo) go to a pump, and see how much you put in . . .

Right, I would do it that way but the pump I go to has a fubar gallon display on it. I'll work on finding a new pump to fill up at, this one is the cheapest in our little one horse town

nickofoxford · #9 05-02-2009, 12:33 PM

Does anyone happen to know any proper way of dismantling the odometer? I can't find any pictorials so far, but I'll keep looking.

moon161 · #10 05-02-2009, 12:42 PM

dieselgiant.com

Shawn T. W. · #11 05-02-2009, 07:41 PM

Quote:

Originally Posted by nickofoxford

Right, I would do it that way but the pump I go to has a fubar gallon display on it. I'll work on finding a new pump to fill up at, this one is the cheapest in our little one horse town

Get a reciept . . . that will tell you . . .