Parts Catalog Accessories Catalog How To Articles Tech Forums
Call Pelican Parts at 888-280-7799
Shopping Cart Cart | Project List | Order Status | Help



Go Back   PeachParts Mercedes-Benz Forum > Mercedes-Benz Tech Information and Support > Diesel Discussion

Reply
 
LinkBack Thread Tools Display Modes
  #1  
Old 05-25-2004, 08:53 AM
Registered User
 
Join Date: Aug 2001
Location: Arkansas
Posts: 141
240D mpg??

I flew to Dallas last week to pick up my 1982 240D with manual transmission.

This is my first diesel vehicle, and I was expecting it to be slow, but it is better than I expected it to be, maybe because I had read so much about how slow they were.

I found an old original advertisement on the internet for the 1982 240D, and it claimed 27 mpg combined, and 33 mpg highway.

Well on my trip back from Dallas to Little Rock, at speeds of around 60-65 mph, on relatively flat interstate, my mileage was only 27 mpg.

On the next tank, which was a combination of city and highway, with some Ozark Mountain foothills in the mix, my mileage was only 24 mpg.

Are there any adjustments, or anything to improve the mileage? The motor sounds great, and runs smooth, and does not seem to smoke at all.

Thanks,
George

Reply With Quote
  #2  
Old 05-25-2004, 09:05 AM
oldnavy's Avatar
Registered User
 
Join Date: Apr 2004
Location: SwampEast MO
Posts: 1,695
The 33 mpg is for 55 mph. Remember when the car was new the speed limit was 55 mph.:p Also yo may need new fuel filters, screen in the tank may need cleaning and you might need something run through the system to clean things like your fuel lines and injectors. I used some biocide followed by a tank of B100 and I'm averaging about 27 mpg around town in my 83 automatic and highway seems to get me about 30-32 mpg at 60-65 mph.
__________________
'10 Chrysler T&C Stow-N-Go White. Grandpa's ride.

'13 Chrysler 200 Touring Candy Red. Grandma's ride.

Age and cunning will always over come youth and vigor.
Reply With Quote
  #3  
Old 05-25-2004, 09:08 AM
junior member
 
Join Date: Oct 2001
Posts: 592
my guess is that you will receive responses that will suggest that fuel mileage varies considerably from car to car. and that you should check valve adjustment and tire pressure. i, driving 20% city and the rest highway at 60 mph, realize overall about 31 mpg in my 83 240d with a manual transmission. this too varies a little with the temperature. better mileage in the warmer months.
Reply With Quote
  #4  
Old 05-25-2004, 09:21 AM
Registered User
 
Join Date: Aug 2001
Location: Arkansas
Posts: 141
Mentioning those filters....

Yesterday when I got back into town from a weekend trip, as I was pulling into my driveway, the car died and would not restart.

I ended up changing the fuel filters, and now it runs fine. But would gunked up filters cause the mpg to be lower??

Is that biocide something that kills the algae that I have heard about that grows in diesel fuel?

Thanks !

George
Reply With Quote
  #5  
Old 05-25-2004, 09:30 AM
oldnavy's Avatar
Registered User
 
Join Date: Apr 2004
Location: SwampEast MO
Posts: 1,695
Quote:
Originally posted by george d
Mentioning those filters....

Yesterday when I got back into town from a weekend trip, as I was pulling into my driveway, the car died and would not restart.

I ended up changing the fuel filters, and now it runs fine. But would gunked up filters cause the mpg to be lower??

Is that biocide something that kills the algae that I have heard about that grows in diesel fuel?

Thanks !

George
Yes, and yes. Clogging filters lowers mpg and robs power by fuel starving engine.

PowerService has a good biocide and you can order through internet and there are several others also. If you do this and you have a lot of algae be ready to change fuel filters again and also check the filter screen in bottom of tank, it's accessed under the car and is a simple job but requires draining the tank. Be sure you order a new O'ring seal for it before you remove the screen.
__________________
'10 Chrysler T&C Stow-N-Go White. Grandpa's ride.

'13 Chrysler 200 Touring Candy Red. Grandma's ride.

Age and cunning will always over come youth and vigor.
Reply With Quote
  #6  
Old 05-25-2004, 10:32 AM
Registered User
 
Join Date: Aug 2001
Location: Milford, DE
Posts: 1,558
How would a clogged filter cause poor fuel mileage?

Seems like a plugged filter would do just the opposite since the restriced fuel flow rate would limit the amount of power you could apply. You could get the same effect by placing a brick under the accelerator pedal. Of course with a 240D you might not notice much of a difference.

One tank of fuel is not enough for an accurate assesment of fuel mileage, if you were running into a head wind on your trip back 27MPG at 65 MPH is not all that bad. If you had the A/C on it was pretty good.

My 81 240D with a rebuilt engine (420 PSI compression, fuel and valvle timing perfect) automatic would return a pretty consistent 28 MPG on the highway, maybe 24-25 around town.

Check a couple of tanks before worrying about it too much - If its still not up to par I'd check for chain stretch, IP timing and valve timing and compression.
Reply With Quote
  #7  
Old 05-25-2004, 10:54 AM
Registered User
 
Join Date: Jan 2000
Location: PA
Posts: 5,440
Oldnavy,

I agree with TIM. How would a partially plugged fuel filter cause an engine to burn more fuel when the filter is limiting the amount of fuel the engine is getting.

That's like saying a water restrictor in your shower causes you to use more water.

One other thing about fuel filters: It will be a cold day in hell when both filters plug at the same time. Therefore I suggest replacing the inline filter first because it costs less than the can filter. Then if this doesn't fix the problem, replace the can filter.

P E H
Reply With Quote
  #8  
Old 05-25-2004, 11:19 AM
TonyFromWestOz's Avatar
"The Wizard of Oz"
 
Join Date: Jan 2004
Location: Perth, Western Australia
Posts: 834
A simple way to check the tank strainer is to reverse tha connections of the fuel supply and return lines. If the fuel starvation goes away, the strainer is clogged.
It will not harm the car to drive it like this, but you may need to change your prefilter more often.
__________________
Tony from West Oz.
Fatmobile 3 84 300D 295kkm Silver grey/Blue int. 2 tank WVO - Recipient of TurboDesel engine.
Josephine '82 300D 390kkm White/Palamino int.
Elizabeth '81 280E, sporting a '79 300D engine.
Lucille '87 W124 300D non-turbo 6 cylinder OM603, Pearl Grey with light grey interior


Various parts cars including 280E, 230C & 300D in various states of disassembly.
Reply With Quote
  #9  
Old 05-25-2004, 11:33 AM
Registered User
 
Join Date: Aug 2001
Location: Milford, DE
Posts: 1,558
Thats a good tip.
Reply With Quote
  #10  
Old 05-25-2004, 12:13 PM
The Warden's Avatar
Certified diesel nut
 
Join Date: Mar 2002
Location: Pacifica (SF Bay Area), CA
Posts: 2,946
Another thing to check for is fuel leaks.

When I got my car, I had a leak in my fuel return line back at the tank...ran the car like this for about a year and a half before finaly replacing it. After replacing it, I went from 24-25 mpg to 27-30 mpg. And that's with a turbo 617!

Just a thought...good luck!
Reply With Quote
  #11  
Old 05-26-2004, 11:51 PM
Registered User
 
Join Date: Feb 2004
Location: Wisconsin
Posts: 41
My '82 240D, auto trans with reman MB engine gets 26 mpg with combined freeway commuting @ 70-75 and in-town driving. I regularly got 25 mpg before blocking the egr valve. The original engine which gave out @ 375,000 miles got 25 mpg regularly. All filters, etc. in top shape.
__________________
DHB
Reply With Quote
  #12  
Old 05-27-2004, 02:01 AM
Registered User
 
Join Date: Jan 2001
Location: oregon
Posts: 2,013
I find it interesting that 240 D manual MPG is about the same as I get with my 81 SD. I fill at the same station and get 26 to just shy of 28 overall and 31 hiway ,it dose change a bit with tempiture.My old 115 240 manual is lucky to get 24
but it's been to the moon and back.........

William Rogers..........
Reply With Quote
  #13  
Old 05-27-2004, 07:49 AM
Registered User
 
Join Date: Aug 2001
Location: Arkansas
Posts: 141
Thanks to all for your input!

I guess I was hoping to get more like 30 mpg with the manual transmission.

I have changed the filters, and will check the return line to the tank.

When I got back to town from picking it up in Dallas, I was determined to get the oil changed ASAP. My independent was golfing that day, so I took it to the Mercedes dealer. The service writer and several mechanics all crowded around to take a look at it! They could not believe that it was in such good condition. That made me feel good.

Thanks again.

George
Reply With Quote
  #14  
Old 05-27-2004, 08:10 AM
oldnavy's Avatar
Registered User
 
Join Date: Apr 2004
Location: SwampEast MO
Posts: 1,695
Quote:
When I got back to town from picking it up in Dallas, I was determined to get the oil changed ASAP. My independent was golfing that day, so I took it to the Mercedes dealer. The service writer and several mechanics all crowded around to take a look at it! They could not believe that it was in such good condition. That made me feel good.
Glad to hear that. That alone was probably worth $500 at the moment just for the peace of mind.
__________________
'10 Chrysler T&C Stow-N-Go White. Grandpa's ride.

'13 Chrysler 200 Touring Candy Red. Grandma's ride.

Age and cunning will always over come youth and vigor.
Reply With Quote
  #15  
Old 05-27-2004, 08:39 AM
Registered User
 
Join Date: Apr 2004
Location: Ojai CA
Posts: 181
For William Rogers, I was suprised too going from my 115 240 manual to the bigger, heavier SD that my mileage was better (once I fixed the return line that kept popping off) but did some reading and the turbo actually makes the engine more efficient with the better fuel burn...

__________________
'84 300SD veg-oil bliss
'83 300SD veg-oil beater
Reply With Quote
Reply

Bookmarks

Thread Tools
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is On
Trackbacks are On
Pingbacks are On
Refbacks are On




All times are GMT -4. The time now is 04:46 AM.


Powered by vBulletin® Version 3.8.7
Copyright ©2000 - 2024, vBulletin Solutions, Inc.
Search Engine Optimization by vBSEO 3.6.0
Copyright 2024 Pelican Parts, LLC - Posts may be archived for display on the Peach Parts or Pelican Parts Website -    DMCA Registered Agent Contact Page