300D is VERY slow from a standing start!

[edge]

I just purchased a 1984 300D and am dissapointed how slow it is from a standing stop. Especially on an incline, I have to floor it and patiently wait for the turbo to kick in. On-ramps on highwyas are scarry. On the highway it's fine at speed. Am I losing compression? Do this NOT affect highway speeds? I knew they were slow but this seems ridiculous! Help!

[william rogers]

Have you been used to driving a gasoline powered car? My 81 Sd take off in second gear and I have adjusted to it .My tired old 74 240 D is a slow match for a bicycle at a stop light.last summer I built an 81 Chevy 2wd Blazer with a warmed up 454 talk about contrast! would not trade my diesels for anything.
William Rogers.........

[Zoonhollis]

Edge,

I was also dissatisfied when I first got my '84 300D. With some care and patience, I think there are some things you can do to speed this car up a bit. Once tweaked, the turbo-diesel model should do a respectable 13 or 14 seconds from 0 to 60 mph. Try the following:

1) Disable the EGR

2) Remove play in the various throttle linkage

3) Change pre and main fuel filters

4) Make sure hollow bolt at intake is free of crud. Ditto for switchover valve

5) Carefully adjust wastegate spring tension

6) Carefully adjust ALDA to enrich fuel/air mixture if running too lean, especially after adjusting wastegate for more boost

This site has excellent sources for the details to the above suggestions. Additionally, Easley and Ritter's MB site has procedures for the wastegate adjustment. Proceed with extreme caution when attempting numbers 5 and 6 above.

How do I know this stuff works? I've done every one of them, and my 300D now performs ALMOST like a gas model!

[edge]

I will try all the things that you mentioned including testing the turbo. I've got to get this car faster! Thanks...

As William indicated, they start off in second gear for the most part. I've found that from a stop, if you need or want the fastest acceleration possible, select L and once you have started to accelerate shift to D and you will go through all four gears. The L position, according to the owners manual, starts the trans in first and will shift to 2nd only. This is for pulling a trailer. The S position is for slopes/grades and limits the trans to 2nd and 3rd gear only, i.e. start in 2nd from a stop and up-shift to 3rd only.

You can try this until you get all the rest of it adjusted and tweeked. Good luck!

[Zoonhollis]

There always seems to be debate over the topic of which gear these diesels start in. My 300D starts in 1st gear 90 percent of the time, and the 10 percent when it starts in 2nd, it downshifts immediately to 1st when I give it a little throttle. I once had a 240D that started in 2nd (as if 1st would have yielded too much acceleration...hah!), but if I put it into L, then into D at a stop, it would start from 1st.

...so the debate continues.

[william rogers]

when I start in L my sd takes off much faster ,but you sure got to keep an eye on the tach.........
William Rogers........

Your problem sounds normal.

My 84 300D turbo drives like that too. My solution, park it in the garage and drive the other cars. It gets on my nerve when its so darn slow!

[edge]

Apparently the previous owner had this 300D sitting aroung for 6 months before I bought it. After runnig it this past week it's much better. It must be a combination of filling up with new deisel, running it on 5000 rpm on the highway and getting use to driving a deisel. Whether I start of in L or S, it always starts out in 1st, so I start in L generally. I love the way the transmission shifts sportlike (later) when I am accelerating...it shifts to a higher gear when I back off the accelerator. Next week I am having a mechanic add a new A/C compressor and converting it to the new RF-134(?) refrigerant for around $500-550, otherwise my wife won't drive it. This car is a replacement for the 1998 C230 I have coming off lease this month. I went to Costco this weak and fit 9 cases of gatorate, arizona ice tea, etc in the trunk! They don't make trunks this large anymore in a mid-size. I love the car now and hope to keep it forever! Mercedes-Benz aren't made like they used to make them. My ML320 is getting a ring job at only 32K miles! Thank goodness it is under warranty and is leased. When it comes off lease next April, I'm replacing it with a used wagon.

5000 rpm? how did ya get that? mine wont go above 3500 in drive and thats doing 90 mph my car is only a year older than yours... 80 cars always did suck but these benzs seem like a real prize to own
cant ask for a more reliable car

[edge]

5000 rpm's when I am accelerating in S, I keep it there for a little while to flush through the system...oh, the engine has to be warm.

[Robby Ackerman]

Edge

Zoonhollis said it all. Bypass the overboast protection relay and see if you pickup 10 seconds or so on your 0 to 50/60 time. It is on the firewall behind the brake booster and inline between the intake manifold and the aneroid compensator on the injection pump. When they go bad 0 to 20 takes about 9 seconds. Once you get it up to speed it runs okay but then runs out of steam at about 65/70. This car can run easily at 80+ with a top speed of around 105. My 83 300 D does a 0 to 50 in about 10.4 secs which is about as good as you can get. I've adjusted the boost from .6A up to .9A.