85' 300D Turbo Power questions - PeachParts Mercedes-Benz Forum

first300D · #1 10-08-2008, 03:11 AM

Hi all,

I usually just drive around DFW. 50 miles here or 50 miles there.
But a couple of weeks ago I had the opportunity to drive my 85' 300D Turbo to Austin for the week on business. As I was there I was reminded how the Austin area has some HILLS

Well one evening on our way to dinner ( 4 adults ) we had to climb this rather large hill. For those of you that know Austin area we went to the Oasis on Lake Travis. Well I saw the hill so I speeded up on the flat preceding the hill thinking this would help. Well once we hit the hill and started up we started slowing and she started smoking. Once at the top we had slowed so much she down shifted to take us over the top finally. Although she made it I was beginning to wonder.

I've had the car for 2 years now but just never had that hill test.

So tell me does this seem normal or does this lead some of you to think I may have a problem exisitent or emerging ?

Let me know and ask what you must and I'll try to answer. I'm really curious of what you think.

TylerH860 · #2 10-08-2008, 03:25 AM

Depends on the hill (and the size of your passengers), but its probably not a big deal. If its not driven "spiritedly" every once in a while she'll belch smoke when you finally do. I assume the smoke was black?

Ol' Turbo has yet to leave a smokescreen anywhere, same goes for Norm, but I have driven many that do. One particular SD was owned since new by an elderly couple that probably never revved it above 3500 rpm or adjusted the valves in years.

#3 10-08-2008, 09:17 AM

Is it a Kalifornia model?

first300D · #4 10-08-2008, 11:20 AM

No its not a Kali Car.

I'm not so much worried about the smoke as I was the progressive loss of power. I am ok that it would not accelerate but guess I wasn't expecting it to just fall off as it did.

I've only driven this 300D and non other. So maybe I should have it looked at and evaluted by others whom have driven many more.

Also, I'm thinking its time to have the values adjusted again. Did it as I purchased and figure it would be worth it to have it done again.

BTW she has 236k miles.

winmutt · #5 10-08-2008, 11:55 AM

Clogged muffler, new air filter.

You silly flat landers.

rrgrassi · #6 10-08-2008, 12:01 PM

Also fuel Filters...

I live near Greenville, TX and there is a good hill on I-30 just west of Rockwall. Going up it, everything loses a bit of speed.

first300D · #7 10-08-2008, 05:28 PM

I drive I30 near Rockwall but don't recall much of a hill ,, unless you mean that small bump as your going east and have just gone past the Lake ?

This Lake Travic Hill in Austin was larger. But then again I don't have 4 passengers alot of the time. And one of them was a Salesman , I was hoping that his hot air would counter act his weight in the car

first300D · #8 10-08-2008, 05:30 PM

Ok I've heard of several potential Clogged items but not a Clogged Muffler ?

Can this really happen ?

winmutt · #9 10-08-2008, 05:34 PM

Quote:

Originally Posted by first300D

Ok I've heard of several potential Clogged items but not a Clogged Muffler ?

Can this really happen ?

Of course.

johnathan1 · #10 10-08-2008, 05:34 PM

Sounds pretty normal to me...

There is a pretty steep hill coming back to LA from the Ventura area, that my 300CD couldn't muster over 45MPH going up...had tons of power at all other times tho. These diesels have a fair bit of torque for chugging up the hills, but they are gonna do it slowly since they are so heavy and lacking some power. :\

curtludwig · #11 10-08-2008, 09:28 PM

I expect you've carboned up your engine with short runs and lacking in hills. On the two MB diesels I've put big miles on each has hit a point where it felt like it was losing power then belched a HUGE cloud of smoke and then ran like a new car.
On my 190D it was combined with a horrible shuddering, I though the car was going to explode. I drive a 55 mile (one way) highway commute so the engine gets good and hot and burns off any carbon. Short runs around town will build up carbon in the engine especially if you allow the car to shift into top gear and low speeds.
A friend has an '80 300SD and once a year he turns it over to me for a weekend. I flog the crap out of it (I live in the little mountains for central MA) for a couple days and give it back, he's always amazed by the power its got when I return it.

Cr from Texas · #12 10-08-2008, 09:58 PM

I've done that very same hill within the past year with the cruise control on.
It almost maintained the set speed.
Did smoke some but that was all.

Cr from Texas · #13 10-09-2008, 01:27 AM

Check out the accelerator linkage. I had a similar loss of power as I wore out the ball connection on the accelerator linkage. Mounts to the firewall. If it's worn enough, the linkage will not fully engage the full range of motion to the IP.

Brian Carlton · #14 10-09-2008, 01:45 AM

The '85 has 2.88 gears and can suffer a bit due to lack of available horsepower on hills.

It's imperative to hit the hill with an engine speed of at least 2800 rpm. This means that you've got to be moving 65 mph. That's a bit fast for climbing speed with the available horsepower, but, the alternative..........going 50 mph..........drops the engine speed to below the full available turbo boost and the vehicle doesn't have a prayer.

I've got a decent hill in CT that I can just barely hold 65 mph for the full 40 second climb. But, I'm the only one in the vehicle. If it had four people in it, it could never hold 65 mph and would lose speed rapidly once it fell below 60 mph.

Your solution should be to drop the transmission into third gear as soon as the engine speed falls to 2650 rpm.........about 60 mph. At that point, it will spin up to 4000 rpm and you'll have full HP for the hill. It will easily hold 60 mph for the remainder of the hill. Do not wait until it falls to 45 mph and finally does a 4-3 downshift itself.