Question about Acceleration - PeachParts Mercedes-Benz Forum

Razz · #1 02-13-2015, 09:29 AM

Hello, I'm new to the forum but I didn't see any posts on this subject. A lot of other posts have been a big help.
I just bought a 1983 300D non turbo as a fixer upper. I've driven a lot of diesel school buses but never a diesel car; always wanted one.
I know that the non turbos are really slow when starting out, but it seems like I have to really push the accelerator all the time. Even at highway speeds, it is pretty stiff, and if I let my foot off the pedal it immediately slows down, like it's dragging weight behind it.
Is this normal or is it something that probably can be fixed? Thanks for input.

shertex · #2 02-13-2015, 09:33 AM

First thing that comes to mind is perhaps you have some sort of fuel or air restriction. Have you changed the air and fuel filters yet? That would be the first thing I would do.

Maxbumpo · #3 02-13-2015, 09:36 AM

How fast is the 0-60 mph time?

More than 16-17 seconds, and you've got a problem to diagnose and fix.

These cars were built to be very comfortable to drive at high speed for extended periods of time, without cruise control! If the accelerator pedal is stiff and requires excessive force, and you would be pretty miserably if you had to keep your foot on it at highway speed all day long, then something is wrong in the linkage.

southofantarctica · #4 02-13-2015, 10:26 AM

Check to see if the rubber ball looking part of your throttle linkage good. Mine had disintegrated and caused poor power because I wasn't getting full movement. It also caused my linkage to slightly bind making it hard to move. Just something easy to check.

shertex · #5 02-13-2015, 10:29 AM

In any case I would certainly lube the throttle linkage....ATF works fine.

rscurtis · #6 02-13-2015, 10:30 AM

Quote:

Originally Posted by Razz

Hello, I'm new to the forum but I didn't see any posts on this subject. A lot of other posts have been a big help.
I just bought a 1983 300D non turbo as a fixer upper. I've driven a lot of diesel school buses but never a diesel car; always wanted one.
I know that the non turbos are really slow when starting out, but it seems like I have to really push the accelerator all the time. Even at highway speeds, it is pretty stiff, and if I let my foot off the pedal it immediately slows down, like it's dragging weight behind it.
Is this normal or is it something that probably can be fixed? Thanks for input.

Look for dragging brakes, or worse, a locked stator in the torque converter. Verify that it's actually shifting into 4th gear.

bricktron · #7 02-13-2015, 10:46 AM

another thing common on automatic transmission cars is that the accelerator pedal wears a piece of its hardware loose, which eats up a chunk of movement. (i'm paraphrasing because i have a manual.)

t walgamuth · #8 02-13-2015, 10:48 AM

If it actually is a non turbo it is a Euro engine most likely. The 300 euro non turbos are pretty peppy especially with a stick. (compared to a 240).

Phillytwotank · #9 02-13-2015, 10:52 AM

brakes could be dragging. Check for a hot wheel

vstech · #10 02-13-2015, 11:27 AM

Quote:

Originally Posted by Razz

Hello, I'm new to the forum but I didn't see any posts on this subject. A lot of other posts have been a big help.
I just bought a 1983 300D non turbo as a fixer upper. I've driven a lot of diesel school buses but never a diesel car; always wanted one.
I know that the non turbos are really slow when starting out, but it seems like I have to really push the accelerator all the time. Even at highway speeds, it is pretty stiff, and if I let my foot off the pedal it immediately slows down, like it's dragging weight behind it.
Is this normal or is it something that probably can be fixed? Thanks for input.

Welcome to the forum.
It would be great to meet you and your car, so can you post up some pictures of the car, showing the engine, the body, the interior, and the dash?
Like mentioned above, by 83, the 300D was a turbo vehicle in the US, so if yours is not, it has had a transplant, or it's from Europe.
The euro 300NA's had the peppy M pump, and it's a bit different from the U.S. version IP.
Lots of good suggestions on here so far, let us know what works or not!
John

Razz · #11 02-13-2015, 11:28 PM

Thank you for the responses. It is a transplant from Germany from what I understand. I bought it from a mechanic shop where it was sitting out and not being driven. They told me the previous owner brought it from Germany and then got to where he only drove it while in country. Only has 175,000 miles on it so I believe them.
I'm trying to figure out how to post pics without website URLs. I'll try to post some later.

vstech · #12 02-13-2015, 11:45 PM

you can upload the images directly to out server by using the go advanced button.

Razz · #13 03-20-2015, 04:13 PM

Today I removed the spring from the throttle and now the car accelerates great. No longer have to push hard on the pedal.
Prior to that, i followed your advice and lubed the linkage, etc. But the spring is what was causing the trouble.