I need some advice. I bought an '84 300D after doing a lot of research. This is my first diesel. The reason I wanted a MB diesel is because I was looking for safety, reliability, longevity, and fuel economy. Because I did my research, I expected it to have slower acceleration than a gas engine. Everyone says I drive like an old man anyway so I didn't think the slowness would be a problem. And this car is very, very pretty. But I'm about ready to take it back to the seller because it's driving me crazy. I'm looking for advice before I take it back.

It is slow. Very slow. I would say dangerously slow. It's a turbo too, so I expected that to help out a little. It doesn't seem to. I honestly don't know how I'm going to pull onto the highway under heavy traffic. I don't even have enough confidence in it to pull onto a major street unless it's at a traffic light. Is this me? Is this just something I have to get used to? Are there any adjustments I can make or things I need to look at to make sure it's not the car? Never having had a diesel, I'm not sure what is normal. How slow is too slow?

And the shifting. It's an automatic but I think it shifts very hard. Each and every shift to a higher gear is punctuated by a loud clunk. Again, is this normal for the car or do I have a major transmission problem?

I'm not even going to get into all the little things inside of the car that don't work. The passenger window just got stuck in the open position on me this morning (and it was cold out too). This little knob is missing, that little knob doesn't work.

I have never bought a car this old or with this many miles. I have wanted this car for a long time and now that I bought it, I wonder if I did the wrong thing. I don't know if I just need to find some patience or if I bought a lemon. I really feel like I'm in over my head here.

This morning I got so annoyed with it that I turned around, went home, and drove my Taurus wagon to work. How sad is that?

Anna:

I just bought a 300 turbo and love it. If yours is a turbo, get it checked. Mine is not fast, but it is not slow, except for the first 90 seconds in the morning. You have to push the pedal to the metal, stomp on the accelerator pedal. These cars need a heavy foot.

I assume your compression is okay, if it starts okay in the am. have your mechanic check valves, timing, boost pressure, maybe your fuel injection.

I too have some little things that need fixing (rear windows not working, some dash lights out) but these are 15-20 year old cars which may last another 15-20. They do need maintenance, but figure you are only going to fix most of these things once, and then you can forget about them. Every new owner of a used MB has to shell out some $$. Just find a good and reasonable mechanic if you don't have one. Check this site for some recommendations.

Don't give up yet.

Peter
1985 300TD

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Peter
1985 300TD 4-speed 212K
1992 400E 343K
2001 E320 72K

oh yeah, your transmission could just be a vacuum problem. Easy to check out and not a pricey fix, if that's what it is, and that does seem to be common fix.

Good luck
Peter
1985 3090TD

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Peter
1985 300TD 4-speed 212K
1992 400E 343K
2001 E320 72K

Explain that vacuum problem to me. It starts right up in the morning so I'm assuming the compression is ok. Is the vacuum the same thing that powers the locks. They are very sluggish and I was already wondering if I had a vacuum problem there.

Your car has a vacuum modulator, run off the vacuum system, that governs your transmission shifts. They fail, sometimes.
But if your locks are sluggish, you may have a leak somewhere, which is affecting your shifts. I am not an expert, but, unless you plan to do the work yourself, take it to someone who knows MBs and they'll know what to do.

Hope that helps.

Peter

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Peter
1985 300TD 4-speed 212K
1992 400E 343K
2001 E320 72K

Anna:

A 300 Turbo should be acceptably fast, unless the last car you had was a road rocket! You do need to get used to a couple oddities in these cars:

Initial acceleration will always be sluggish -- the first few feet will be slow. It's the nature of the engine, having to do with how the fuel gets into the combustion chamber. Gasoline engines are "throttled" -- strangled is more like it. Diesels suck down huge amounts of air all the time, and the fuel is injected into the combustion chamber and "lit" by the heat there. Takes more time to come up to speed.

Get used to having your foot on the floor, hard. You have to hold the electric kickdown switch down to get maximum engine speed for each gear.

The turbo doesn't do much until the engine speed is up to 1500 rpm or so, and if you let your foot up too soon, the turbo slows down, you lose horsepower, and the transmission will upshift, all at the same time. Takes 5 sec or so to get the tranny back down a gear and the turbo up to speed again after you floor it and downshift the tranny -- terrible lag.

I've found the best way to drive these things is to take off gently -- no more than half throttle -- until the turbo comes up, then give it more pedal.

These models also sit in second gear, only downshift into first when you open the throttle. I'm sure that if your locks aren't working correctly that the vaccuum to the transmission isn't correct, either. By the way, it takes a couple seconds for the locks to work, not like the 'snap' of electric locks.

If you are going to have someone work on the car for you, have them check the pressure lines from the intake manifold to the ALDA (it's on the injection pump, tells the pump to put more fuel in as the intake pressure goes up) -- if these lines are plugged, it's the same as not having a turbo. There is also an over-boost protection switch that vents this line in case the turbo runs away -- if it is bad, you don't get extra fuel and the engine only develops about 90 horsepower!

Good luck -- I suspect you will learn to love this car!

Peter

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1972 220D ?? miles
1988 300E 200,012
1987 300D Turbo killed 9/25/07, 275,000 miles
1985 Volvo 740 GLE Turobodiesel 218,000
1972 280 SE 4.5 165, 000 - It runs!

A change of heart?

http://cgi.ebay.com/ebaymotors/aw-cgi/eBayISAPI.dll?ViewItem&item=598210786

Gee. Vehicle has no problems.

Tilt steering? naaaah....really?

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Matt
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1995 E300 Diesel (Die Blau Frau)

I hate to see you give up the ghost so quick. I live in an area where the majority of the roads are two lane 55 mph. On my 18 mile drive to work I usually only see a handful of cars (I am usually at work at 5:30 am). More traffic on the way home but still I do not see where the 300D is so slow that it is dangerous. Granted I have modified a few things on mine to insure that the turbo contributes it's part. I just bring it up to 60 mph and set the cruise control. I am not anticipating any problems once the 240D is usable for commuting. I still can't find the "tilt" adjustment for my steering . If you can find someone in your area that has this same car you should let them drive it or drive theirs to compare.
If you want speed in a diesel look at a 1998/99 E300.

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Jim

My husband has a friend who is a MB mechanic. He looked at it and said that it runs the way it is supposed to. His advice to me - buy a gasoline car. I wanted diesel because of the fuel economy and longevity. I wasn't prepared for how it drove! I think you guys are right - it takes a certain kind of person to drive a diesel.

Darn, I forgot to ask about that tilt steering. I'll look at it tonight.

"If you want speed in a diesel look at a 1998/99 E300" - Ha, ha! If I could afford that then I wouldn't be in the pickle I'm in now!

Conversation with my husband's friend:
Me:"I think something is wrong with my 300D".
Mechanic: "Let me guess, it's too slow."
Me: "Yeah, exactly."
Mechanic: "That's how it is supposed to be."
Me: "Not this slow."
Mechanic: "Yes it is."
Me: "Let's go for a ride and tell me what you think."
Mechanic: "Anna, all of them are like this."
Me: "Really?"
Mechanic: "You're not a diesel driver. Why don't you just sell it to someone who is."

So now I feel like an idiot for buying something I didn't know enough about. And my husband "told me so". Rats.

My 1984 300SD isn't really that slow (it has the same engine as your 300D). Maybe you should buy some diesel fuel additive. Everyone here adds something to their fuel. Also, you could have a clogged fuel filter that is causing the engine to starve for fuel. That is a major source of sluggishness (or even stalling) in diesels. Another thing I do in the morning on a cold engine is rev the engine to about 1250 rpms for one minute. Diesels run much better after a short warm up than taking off immediately.

You need to adjust the way you accelerate. I usually has to push the pedal more to accelerate from a dead stop than a gas engine. But, when you can feel that engine is going to shift, back off the accelerator a tiny bit or else you'll get a hard shift. If you want to go fast, just floor it and expect the car to shift hard. This firm shift is common with Benzs (even gasoline Benzs) I noticed.

Also this car is not going to burn rubber to the next light (and beat Carmaros and Mustangs), the engine has sufficient power to keep up with reasonable traffic. I do mostly city driving.

Anna,

From your description, I don't think that this friend who is an "MB mechanic" is up on these cars. When these cars were new, every tech in the shop knew what to expect from them. A good friend of mine is a tech at an MB shop and a VERY GOOD ONE, but he admits that he sees very few of these 15 to 23 year old cars. So nothing against your friend, but he may have very little experience with them.

I expected when I read your original posts that you would get a flaming thread with people telling you all about the ALDA adjustment. psfred was the only one who pointed it out, but it was buried in his long post of very useful information.

Go back and read the last paragraph of his post, and find someone who is totally familiar with these cars and have him set this system up properly.

Don't give up that easily. My wife had a station wagon like yours that was slower than an automatic 240D until we figured this out. After that it felt like a dragster, relatively speaking. Unless you came out of a very fast car, this car should not feel like you describe.

FIND SOMEONE WHO IS VERY FAMILIAR WITH THESE CARS AND HAVE HIM CHECK THE ALDA ADUSTMENT!

Hang in there and stick to your guns,

Anna,

I hereby echo Larry's exhortation not to give up on this car. While I do not consider myself an expert on the ALDA adjustment, I was able (with the advice from more knowledgable folks on this site) to tweak its setting, along with a slight turbo boost adjustment. Now when I take off from a dead stop, this car (a 1984 300D-T) throws my head back. Admittedly, I may be cursed with a weak neck, but I really think it's because my car is now more than satisfactory in the "get up and go" department, and it's because of the following:

*ALDA tweak
*Turbo boost pressure adjustment
*Proper fuel and air filter changes
*Frequent inspection of the turbo boost line running from the intake to the switchover to the ALDA (it can get clogged)
*Removed play in throttle linkage
*Disabled the EGR

Go get 'em!

-Matt

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Matt
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1995 E300 Diesel (Die Blau Frau)

Anna,

I hereby echo Larry's exhortation not to give up on this car. While I do not consider myself an expert on the ALDA adjustment, I was able (with the advice from more knowledgable folks on this site) to tweak its setting, along with a slight turbo boost adjustment. Now when I take off from a dead stop, this car (a 1984 300D-T) throws my head back. Admittedly, I may be cursed with a weak neck, but I really think it's because my car is now more than satisfactory in the "get up and go" department, and it's because of the following:

*ALDA tweak
*Turbo boost pressure adjustment
*Proper fuel and air filter changes
*Frequent inspection of the turbo boost line running from the intake to the switchover to the ALDA (it can get clogged)
*Removed play in throttle linkage
*Disabled the EGR

Go get 'em!

-Matt

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Matt
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1995 E300 Diesel (Die Blau Frau)