Mercedes-Benz Forum banner

1 - 20 of 25 Posts

·
Registered
1979 240D
Joined
·
8 Posts
Discussion Starter #1 (Edited)
I am 17 and have just recently purchased my first car. It is a 1979 240d. The body is near perfect, and the intereior is pretty clean. i picked it up for $2000, seemed like a good deal. It currently has 174,000 miles on it. But the one issue i have with it is it is so SLOW. It almost doesnt seem normal. I struggle going up my drive way. What are somethings i can check too maybe increase the performance? i am new too all this and could use all the advice possible.
 

Attachments

·
CH4S Admin , Outstanding Contributor
1985 500SEC, 1991 190E 2.6.
Joined
·
40,685 Posts
Convert to 300 turbo diesel?

Please click 'User CP' on the top toolbar to complete your profile with car mod and location, to make it easier for members to reply.
Moved to the W123 (your chassis) sub forum.
Welcome
 

·
Registered
1984 300D
Joined
·
5,070 Posts
Well, I bought a 84 300D Turbodiesel. It was scary slow on the low end. Once it was going it drove normal.
In my case the throttle linkages were extremely sloppy so when I put my Foot on the Accelerator the Throttle Lever at the Fuel Injection pump simply was not moving enough.
Tightening it up fix it.
Note: In the Factory Service Manual there are specific lengths for the various Throttle rods and there also is more than one linkage setup; even for 300Ds.

Also the Throttle Linkage Bell Crank on the Fire wall can be worn out. Again there is different ones. On mine unseen is a Plastic Ball that can just crumble away and in the front there is a Rubber Part that can fail.

If you were to go to an interview to get a job as a Diesel Mechanic one of the questions they are going to ask is something like this: "The Truck Driver complains of low plower; what do you think the most likely cause is".
The answer is the most likely cause is restricted Fuel Filter/s (this includes the Fuel Tank Screen). The next part of the Answer would be the same but for the Air Filter except that is not the Best answer because they did not say the Driver complained of low power and smoke.

The of trying to regain lost power is trying to get the Engine back to being as close to new specs as is resonably possible.
Valves need adjusting (no Hydraulic Valve Lifters on your Car), Valve Timing has to do with the Timing Chain and Timing Gear Wear, Fuel Injection Pump Timing and if the Fuel Injectors are within spec (if you have the original Injectors unless they were extremely well cared for are over due to be rebuilt).
I guess you get the picture.

Also get under the Car and check the Transmission and Engine Oil Cooler hoses, you have 2 rubber Flex Discs on the Drive Shaft, a Rubber Driveshaft Support Mount and 4 Rubber Boots on your Rear Axles. All should be checked for the rubber going bad.

If a Flex Disc goes it has been know to tear the end of a Transmission off, People have lost Engines due to the Oil Cooler Hoses going while driving and the Mercedes Fills the rear Axles with Oil so if the Boots go the Oil leaks out.
 

·
Registered
1979 240D
Joined
·
8 Posts
Discussion Starter #4
Thank you!

Thanks guys, a lot of helpful information, ill make sure to check on those things. sorry i am still new to the sit
 

·
Registered
1983 300SD, 2013 C250
Joined
·
374 Posts
Sweet car! I want a w123, trying to get money. Hopefully I will have enough next summer when I come back from college. Welcome, and awesome car! You will stand out from all the other teen drivers in that you have a sweet car.
 

·
Registered
1999 E320, 1975 450SEL, 1979 280SE
Joined
·
377 Posts
Just a quick note... If you don't know it, the car normally starts off in second gear. (automatic trans.) If you mash the gas pedal to the floor (from a stop), the car will start out in first gear and have some more pep. Hold the pedal down hard and it will wind out pretty good and then, it hits second. (The throttle linkage should be in good shape for this.) Another way to start out in first gear is to put the shifter in L and go from a stop. Give it gas and then shift up manually. Have you tried this? Let us know if this helps!
 

·
Registered
1981 W123 300D non turbo, 1992 190E 1.8 <=> 2.0
Joined
·
6,561 Posts
Hello and welcome! That's a nice car, great find. I'm glad to see the younger generation appreciating these fine cars.
You make yourself sound like an old man - we all know that's not the case!
 

·
Registered
1979 240D
Joined
·
8 Posts
Discussion Starter #9
Just a quick note... If you don't know it, the car normally starts off in second gear. (automatic trans.) If you mash the gas pedal to the floor (from a stop), the car will start out in first gear and have some more pep. Hold the pedal down hard and it will wind out pretty good and then, it hits second. (The throttle linkage should be in good shape for this.) Another way to start out in first gear is to put the shifter in L and go from a stop. Give it gas and then shift up manually. Have you tried this? Let us know if this helps!
Yes! When we test drove the car we did try to manually shift, it did seem to help, wasn't sure if it was good for the car or not.


Sent from my iPhone using AG Free
 

·
Registered
1999 E320, 1975 450SEL, 1979 280SE
Joined
·
377 Posts
If your Benz is in good shape, and it appears to be, shifting the gears manually should not harm it. I can only tell you that I had a '78 300D with the same trans set up (starting off in second). I used to either floor the gas pedal from a standing start or start off in L very often. That car had over 300,000 mi on it when I sold it! I would do some of the maintenance items that others have suggested, as your budget and time allow. Did you get an owners manual with your car? There should be a maintenance booklet, as well. The owners manual tells about getting the car to start off in the lowest gear. Great looking car! Have fun with it.
 

·
Registered
1999 CL500
Joined
·
677 Posts
hope u did basic research before buying

these cars were slow from the factory, they're slow now and they always will be slow....unless u throw on a different motor and do some un-necessary work, it'll always be slow and you'll always be the dude cruising in the right lane with people passing you all the time

and you'll always have the car with nice lines, an ageless design that is hard not to appreciate, and a tank whose build quality is yet to be rivaled


any 17 year old can have daddy get them a used Civic or Maxima...but your car is unique, and people will appreciate it

all you need is a headunit and some decent speakers....your car looks great! :)
 

·
Registered
1981 Mercedes-Benz 300TD
Joined
·
871 Posts
... you'll always be the dude cruising in the right lane with people passing you all the time...
Unless your like me where your gas petal virtually lives on the floor during highway cruises; I still pass people while in the 300TD at full throttle. After all it is a diesel. Keep in mind I'm also very diligent about proper mechanical maintenance which supports my style. :D



If you had a turbo diesel you would have a few more power options, but at this point the things you can do is:
-Add a low boost turbo (less than 5psi)
-Modify the injection pump(IP) for more fuel flow
-Make sure the valves and the timing are all in spec
-Maybe modify the intake and exhaust to be less restrictive while increasing fuel flow


As a slight remedy, don't be afraid to drive with a heavy foot. Again, because its a diesel and has the forged internals, it will be just fine running at 90% load regularly with good engine oil, at the proper running temp. and with the valves and IP properly adjusted and timed. All things considered, the work and money involved in heavily modifying is not worth it in my opinion. Even if you managed to double the engines power output, you would still have a relatively slow car. Of all vehicles in the world, modifying a 240d is probably the least rewarding so just enjoy it for what it is, make sure its running right and you'll be just fine.
 

·
Registered
'86 W123 200, OM617 non-turbo, bastard 5-speed; '95 W202 C250 Diesel, OM605 non-turbo, 5-spd man
Joined
·
4,273 Posts
Whatever you do, don't keep the revs too low. People have this misgiving that because it's a diesel engine, it is a tractor engine; it's not.
 

·
Registered
1979 & 1985 300D's
Joined
·
2,537 Posts
Yeah, they like to be wound out a bit and driven a bit hard. Just get a heavier boot!
 

·
Registered
1979 240D
Joined
·
8 Posts
Discussion Starter #15
SHE LIVVESSS!!! Just had to swap out the air filter. Runs like a champ. Just need to change the oil tomorrow and she should be perfect. Thanks guys!


Sent from my iPhone using AG Free
 

·
Registered
Joined
·
588 Posts
If your Benz is in good shape, and it appears to be, shifting the gears manually should not harm it. I can only tell you that I had a '78 300D with the same trans set up (starting off in second). I used to either floor the gas pedal from a standing start or start off in L very often.
You could also briefly select L (or 1) and go back to D whilst standing still. This should also result in a 1st gear take-off :)

And yes, those gearboxes are meant to be manually shiftable, for engine-braking in a down-hill situation p.e.
 

·
Registered
Joined
·
21 Posts
That is a beautiful first car.
Once in a while I think my 300 CD is SLOW then I get on the Highway and cruise at 70 and it's like riding in my livingroom.
Good luck with it. An improvement might be had using Diesel Purge (2 Cans) and get the pump timed. Pretty Much what everyone else said. On my 300 if it was P.M. i just did it anyway as i had no REAL service record and service was spotty at best (Family Car).

Also check tire pressure often until you can be sure they are holding pressure. Low tires = Slow accelleration.
 

·
Premium Member
W-1-2-3 Go!
Joined
·
16,161 Posts
You could also briefly select L (or 1) and go back to D whilst standing still. This should also result in a 1st gear take-off :)

And yes, those gearboxes are meant to be manually shiftable, for engine-braking in a down-hill situation p.e.
There are marks on the speedometer telling you the maximum shift points per gear. The marks are laid out as I, II, and III. Be careful when manually shifting the gears on an automatic, especially for a car this old. There are no computers telling you it's too low of a gear and will disallow the action. New cars have this which is great, but these old MB's don't.

Only downshift when you are sure the vehicle speed is within the range of the gear you're selecting.
 

·
Registered
'86 W123 200, OM617 non-turbo, bastard 5-speed; '95 W202 C250 Diesel, OM605 non-turbo, 5-spd man
Joined
·
4,273 Posts
According to magazines of day, Zero to Sixty mph should be 22 to 24 seconds.
Maybe at the coast, with a very basic spec. A magazine in South Africa tested 47 sec for a 240D auto... one of the slowest cars ever tested.
 
1 - 20 of 25 Posts
Top