300sd ? - PeachParts Mercedes-Benz Forum

audiboi2 · #1 11-09-2006, 05:21 PM

Hello, i'm pretty new to the form and just picked up my 1st Diesel Mercedes. I just have a few things that i was unsure about. I have a 1984 300SD and the car is in very good shape and runs well. However i wanted to know if it is normal for it to be very very slow from about 0 to 20? I've heard from others that it is normal, but mine is so slow off the line that it feels dangeres. If this is normal is there anything i can do to improve it, once it hits about 20mph the turbo kicks in and it feel pretty decent. Another thing i wanted to know was if it was ok to cruise at higher speeds, 75-80 mph. When i do this car drives just fine but it rpms are at about 3500ish rpms, is this normal? One more thing when i floor it the engine only rev's to about 3500 rpm's in 1st gear but it rev's to about 4600 rpm's in every other gear. Should it rev to 4600 in 1st also. Thanks for you help.

sixto · #2 11-09-2006, 05:53 PM

I don't know what it feels sluggish in comparison to so it's hard to say. Best bet is to find someone with a good 300SD and compare. You can time a pedal-to-the-floor 0-60 mph run if you can find a place where it's safe and legal to do so. Should be about 15 seconds.

That engine in a good state of tune will run at 75-80 mph longer than you'd care for it to. You won't do it a lick of damage. 3500rpm seems about right.

Are you saying it shifts to second at 3500rpm even with the pedal to the floor? Do you have the pedal down to the kickdown switch at the far end of the pedal travel?

Sixto
93 300SD

winmutt · #3 11-09-2006, 06:02 PM

Quote:

Originally Posted by audiboi2

Hello, i'm pretty new to the form and just picked up my 1st Diesel Mercedes. I just have a few things that i was unsure about. I have a 1984 300SD and the car is in very good shape and runs well. However i wanted to know if it is normal for it to be very very slow from about 0 to 20? I've heard from others that it is normal, but mine is so slow off the line that it feels dangeres. If this is normal is there anything i can do to improve it, once it hits about 20mph the turbo kicks in and it feel pretty decent. Another thing i wanted to know was if it was ok to cruise at higher speeds, 75-80 mph. When i do this car drives just fine but it rpms are at about 3500ish rpms, is this normal? One more thing when i floor it the engine only rev's to about 3500 rpm's in 1st gear but it rev's to about 4600 rpm's in every other gear. Should it rev to 4600 in 1st also. Thanks for you help.

Car starts in 2nd gear. Its called luxury by some.

audiboi2 · #4 11-09-2006, 06:34 PM

Quote:

Originally Posted by sixto

I don't know what it feels sluggish in comparison to so it's hard to say. Best bet is to find someone with a good 300SD and compare. You can time a pedal-to-the-floor 0-60 mph run if you can find a place where it's safe and legal to do so. Should be about 15 seconds.

That engine in a good state of tune will run at 75-80 mph longer than you'd care for it to. You won't do it a lick of damage. 3500rpm seems about right.

Are you saying it shifts to second at 3500rpm even with the pedal to the floor? Do you have the pedal down to the kickdown switch at the far end of the pedal travel?

Sixto
93 300SD

Thanks for the info, I'm glade to hear the 80mph wont hurt it. The car runs very well at that speed, i've even had it over 100mph and it seemed fine (I won't make a habbit of that tho). I did time it from 0 to 60 and its about 13.5 sec. Once its hits about 20mph its pretty fast. If i floor it and push it to the kickdown position is shifts at about 3500 rpm's from 1st to 2nd, but if i floor it and don't push it to the kickdown position it will rev to about 4600 rpms, is that normal? Another thing i wanted to ask is if it is normal for the the transmission to have a firm shift when it is cold, once its run for a few min its smooth.

pawoSD · #5 11-09-2006, 06:46 PM

I'm guessing your ALDA could use some adjustment or shimming. Are you framiliar with working on vehicles? (Before attempting this) If so it can be explained what needs to be done to get some extra umph from a standing start. Even with this adjustment they are not tire-shredders however.

Yours is pretty close to the 0-60 for these cars....so it may be running perfectly fine. If you're used to the lunge-ability of gas cars, it will not be present on the 300sd. For that you'd want a 380se.

MTUpower · #6 11-09-2006, 07:00 PM

Remember when you drive these diesels that you floor it until you reach the speed you'd like and then ease up- you dont slowly accelerate and then when you want more speed lead foot it. Next you ought to do a search on ALDA and how to adjust it. After that do an Italian tune-up and perform all "I just bought the car" maintainence.

audiboi2 · #7 11-09-2006, 07:16 PM

thanks guys, ill see what i can find out about the ALDA. I've done allot of work on gas cars but very little on diesels. Can anyone give me a bit of info on what this does and where it is located? Thanks

MTUpower · #8 11-09-2006, 07:21 PM

Go up the search feature and type in "ALDA"= you'll find umpteen million thread that will answer your questions.

Stevo · #9 11-09-2006, 07:29 PM

Have you changed the air filter, both fuel filters and adjusted the valves?

audiboi2 · #10 11-09-2006, 07:47 PM

thanks, not yet but its something im planing to do asap. The car does have 361k miles on it, is there anything else i need to look out for? Should i be worried about those miles?

Stevo · #11 11-09-2006, 10:29 PM

Quote:

Originally Posted by audiboi2

thanks, not yet but its something im planing to do asap. The car does have 361k miles on it, is there anything else i need to look out for? Should i be worried about those miles?

There are plenty of things too look out for but i would start with those filters, valve adjustment, and Alda check and see if that helps your present problem. While doing your valves check chain stretch. Then crawl under the rear of the car and see if your fuel hoses are leaking at the tank. also check the fuel hoses in the engine compartment. These are just a couple of things that often need attention.