rigid gear shift, accelaration

[biohead]

Greetings, everyone!!
i'm completely new to this website, and am very excited to join this legendary forum!!

i got my "new" 1987 300D Turbo sedan just recently, and i love it. it's my first mercedes, and first diesel, and driving on biodiesel "guilt free" is just fantastic. what a car!!
after fixing and replacing some components like alternator, s/w pump, bushy, tires, etc. (bought it for $3800, put on it additional 2 grand by now) it drives pretty nice.
the only two things that kind of bothering me, still, are:
it's pretty slow accelerating from 0 to 20 mph. above 20 it becomes a rocket. I know from reading many threads it's pretty normal, but after driving a friend's same year SDL i feel my car is somewhat heavy (SDL and D Turbo supposed to have similar engine, correct?)
other thing is that shifting from 1st to 2nd involves some traumatic jump, especially in slow acceleration. is it normal?

my mechanic, which i trust based on his knowledge and work, says regarding these two issues that that's as good as it gets with these old beutiful beasts...

Thank you all and keep it up!
Peace!

[t walgamuth]

on your new 300.

zero to 20 sluggish and big rush after that is normal.

sdl IS a lot heavier than the e class 300d... 3 to 400 pounds i estimate off top of my head.

on the shifting, i would think some adjustment by someone who really knows these trannys might do some good. it shifts good under heavy acceleration? if yes, then the clutches must be strong. then it is a control issue i suppose.

someone will chime in who knows more than me.

tom w

It is not normal for the 603 to be sluggish like a tortuous and then after 20 mph suddenly burst into building boost! Yes, the SDL has the exact same engine.

There are several items you need to check, boost may be delayed due to several causes. The alda fuel enrichment may, or may not be functioning properly and this needs to be checked, also are the vac hoses and switch over valve between the intake manifold and alda functioning properly? Are all your vac hoses routed properly? Have you installed a new secondary fuel filter? Biodiesel can and will loosen up years of sludge in your tank and fuel supply lines and clog even a new filter fast!

Your 87 300D should accelerate from 0 to 60 within 11 to 12 seconds! Acceleration should be pretty much uniform throughout with only a slight notice of the turbo boosting effect at or around 2500 rpm. Your fuel economy should average right around 30 mpg.

Also are other possible issues such as a need for a diesel purge, but that wouldn't help much with your sluggish starts. Read as much as you can in the archives here, as all of these symptoms have been discussed here.

[biohead]

i guess i need to get used to stand on the gas paddle. it does bring about a phenomenal acceleration, but i pay the price at the biodiesel fuel station
i found out that this monster goes about 20 mpg in the city and about 27 highway...which isn't that great. hopefully driving adjustment would help down the road.
all filters were replaced. fuel filters replaced twice in 2 months. vacuum lines are new as well...didn't check that valve you mentioned, but will - thanks!
how come the SDL is quicker with same engine but heavier body??
the turbo rattles when kicks in and my mechanic recommended to go easy on it so it doesn't burst...or overheat
peace, ya' all!

[TwitchKitty]

Originally Posted by biohead

my mechanic, which? i trust based on his knowledge and work, says regarding these two issues that that's as good as it gets with these old beutiful beasts...

Get a mechanic who is a person who knows MB diesels.

[Jim H]

Originally Posted by biohead

it's pretty slow accelerating from 0 to 20 mph. above 20 it becomes a rocket. I know from reading many threads it's pretty normal, but after driving a friend's same year SDL i feel my car is somewhat heavy (SDL and D Turbo supposed to have similar engine, correct?)
other thing is that shifting from 1st to 2nd involves some traumatic jump, especially in slow acceleration. is it normal?

No, the OM603 should make good torque right off the line, and get better at 2,500 rpm. In a W124 body, it is a rocket!

It is a sign that there may one, or more vacuum leaks. Search on MityVac for a tester, and check vacuum lines and the rubber fittings.

A vacuum leak can cause harder shifts.

A boost leak can delay engine torque.

Have a look around and let us know what you find.

[biohead]

Originally Posted by Jim H

No, the OM603 should make good torque right off the line, and get better at 2,500 rpm. In a W124 body, it is a rocket!

It is a sign that there may one, or more vacuum leaks. Search on MityVac for a tester, and check vacuum lines and the rubber fittings.

A vacuum leak can cause harder shifts.

A boost leak can delay engine torque.

Have a look around and let us know what you find.

as my mechanical knowledge's limited, where sholud i take my car for a vacuum/boost leak check?

[ecoshadow]

These forums helped me to clean out the pressure line from the back of the intake manifold to the little plastic turb overboost protection valve on the firewall and the plastic line from that valve to the ALDA. Very easy to do with a 12mm open end wrench, a can of brake parts cleaner and some air pressure. Took about 10min. Major improvement in low end acceleration. Lots of discussion of the problem in these forums under adjusting the ALDA.
Good luck!

[biohead]

Originally Posted by ecoshadow

These forums helped me to clean out the pressure line from the back of the intake manifold to the little plastic turb overboost protection valve on the firewall and the plastic line from that valve to the ALDA. Very easy to do with a 12mm open end wrench, a can of brake parts cleaner and some air pressure. Took about 10min. Major improvement in low end acceleration. Lots of discussion of the problem in these forums under adjusting the ALDA.
Good luck!

sounds like a great idea. i'll give it a try. thanks!!