I am now the proud(?) owner of a 82 300D. I say proud because I own it as a result of my daughter's accident in which I ended up purchasing the car rather than pay the shop cost to repair.

Interior is in excellent condition and the engine has only 170,000 miles. I plan on doing the majority of the necessry body work myself (with some assistance from a pro).

Everything in the car works very well with the exception of acceleration. I had my shop mechanic check it out and everything seems ok. However, the acceleration is extremely poor up to about 3, 000 rpms. He told me this is normal for this auto, but I have trouble with his statement.

MB would never build a car that was this slow off the mark. I don't expect gasoline acceleration, but something better than I have.

Anyone have ideas on what I can check/repair, etc.?

Is it a turbo or non-turbo?

Secondly, do a search under 'zoonholis' as to one of his threads on 'tune up' or 'increasing speed' or something like that.

If you can't find the thread, PM me and I'll cut and paste some stuff. Essentially the answer is "yes". You can improve the acceleration significantly through:

a. Valve adjustment
b. Banjo bolts cleaned as well as their lines
c. ALDA adjustment

etc, etc.

I had the stinkin slowest car off the mark. It had been taken to several places and given the 'thumbs down' ranking. But with the help of the forum, it is respectable now.

Don

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DAILY DRIVERS:
'84 300DT 298k (Aubrey's)
'99.5 Jetta TDI IV 251k (Julie's)
'97 Jetta TDI 127k (Amber's)
'97 Jetta TDI 186k (Matt's)
'96 Passat TDI 237k (Don's
'84 300D 211k Mint (Arne- Undergoing Greasecar Conversion)

SOLD:
'82 240D 229k (Matt's - Converted-300DT w/ 4 speed

guru,

Two things we need to know: Your 0 to 60 MPH time and you elevation.

Then we can compare your times to other comperable cars and conditions.

P E H

0-60 16 sec

700 ft. above sea level

0-60 is a slow 16 secs. (does all right after the turbo kicks in)

Elevation is 700 ft.

Speakin of diesel performance.... probably the most significant feature is the diesel's characteristic of sustaining constant speed without variation unless you come across hills or inclines.

Gotta ditch all gasoline driving habbits, jack rabbit starts and never being able to sustain constant vehicle speed without going through cycles of accelerating and slowing down - if you are going to start appreciating diesel performance.

For this reason alone, diesels are probably safer and less stressful to drive than are gasoline vehicles which always seem to waver in speeds while either braking or accelerating all the time.

I realize that diesel isn't gasoline and I don't expect gasoline type performance. However, something is wrong somewhere with ability of this auto to move off the starting line. Frankly, it is a safety hazard right now.

It takes full throttle just to move and it will NOT pull the hill to my home faster than a walking pace.

As I stated; Once the turbo kicks in there is not problem with acceleration or sustaining speed. My mechanic stated that the turbo in this model/year car does not kick in until you reach 3000 rpms. Again, I don't have a problem with that IF that is true.

The problem is at lower RPMs

I really would like some insight on what needs to be checked, replaced, or modified with the engine before I spend time/$$ on body repair.

OR

Should I just part it out and hope to recoup some of my money
(I really don't want to do this)

Diesel Don mention the banjo bolt and lines which INCLUDES the switchover valve and the lines going to the ALDA. You should be able to blow through the switchover valve, its normally OPEN. If it isn't, disconnect and clean out with carb or brake cleaner. Ocassionally they get so bad, you have to replace them, but not often.

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84 300DT Puke Yellow. Totalled after 438,000
84 300DT Orient Red. 169,000 (actual mileage may vary)
2002 Explorer EB (wife's)

I had/have the same problem with my SD. Dog slow from the start....better once the turbo kicks in.

Banjo Bolt made some difference, as did reterminating my vacuum lines to the proper places.

But still not there.

I'm not going to bad mouth the car till I do a valve adjust, diesel purge and if necessary, ALDA adjust. Highly recommend you take these inexpensive measures before you make any further plans for the car.

just my $.02

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1998 W202 C230 - The money pit of late.
1984 W126 300SD (356,800 miles) Gone to the wrenchapart
1984 W123 300D Gone to the wrenchapart
1972 W108 280SE 3.5 (sold but not forgotten)
1986 Buick Grand National 3.8l Turbo (86k miles)
1966 Glassic Model 'A' Replica http://www.glassicannex.org

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You have a CLASSIC case of low fuel delivery off idle. There should not be a "lag" until the turbo "kicks in". The car should pull strongly off idle (especially at 700ft!) and smoothly build power as the turbo boost increases from about 1500rpm up. The simple fix in most cases is an ALDA adjustment. Do a search on this forum, it has been covered ad nauseum. Be gentle, don't force the setscrew or you risk breaking the aneroid capsule. Usually 1.0-1.5 turns CCW is about right. You'll be amazed at the difference. Trust me.

BTW - when you get it fixed, and it will light the tires up from a standstill (well, on wet or dirty pavement anyway), go back and visit your "mechanic" and edumacate him on how a diesel SHOULD run! I am so sick of hearing that "it's a diesel, it's supposed to be slow" crap!

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Dave
Boise, ID
Check out my website photos, documents, and movies!

Many good suggestions here, and gsxr put it most succinctly. In addition to the above, you may want to do the following:

*Replace pre and main fuel filters
*Tighten up throttle linkage
*Adjust wastegate setting on the turbo. Do a search for this one; it's not for the faint of heart

As with others on the forum, my '84 300D was also sluggish off the line at one time. With a number of tweaks, she ran like a champ, and with little sacrifice to fuel economy

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Matt
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1995 E300 Diesel (Die Blau Frau)

I want to thank all of you who have chimed in here. I was doing a search for a miracle. Low and behold, I got reading this thread. It so happens I have a 1985 300SD with over 200K on the odometer. It was a gift from Dad, and I always thought the same things the mechanics say....Its a diesel...it has to be slow. But it got to a point where I also felt the low acceleration was a driving hazard and I was asking for a major accident if i did not look into what was going on. So, after reading your thread, i did as some of you suggested...I by passed the switchover valve and WOW!!!! my car is back to life. I started laughin when she took off. As I inspected further, I noticed the line comin from the manifold to the switchover valve is pretty cruddy, so I'll have to tackle that soon. My question, however, is...will it hurt my car to have the switchover valve bypassed for a while until I get around to replacing it??? I dont want to ruin anything and I'm kinda new at this. Please let me know

Well.... that depends. If your boost pressure is below the safety switch limit of 1.10 bar (+/- 0.15 bar), then you are probably safe. Hard to tell without hooking up a boost gauge and measuring your boost. You probably just need to clean the banjo fitting, lines, and switchover valve. When that's done, try adjusting the ALDA as well - that can make a big difference in off-idle power. Your SD should manage a 0-60 time in the 15 second range, near sea level anyway.

You have two distinct issues:

1) Acceleration up to the point where the boost kicks in.

2) Acceleration after boost kicks in.

Most of the aforementioned posts provide ample info as to obtain proper boost pressure to solve the issue under number 2 above. I would urge you to purchase a $30. gauge that will measure the boost in all operating ranges to determine if you have full boost (at least 9 psi) and at what RPM you are getting full boost (should be between 2200 and 2400 rpm). This gauge will be of infinite value in pointing you in the right direction. Personally, I was lost without this gauge. It is probably the best investment you can make.

Now, with regard to number 1 above, a properly working boost system and turbo will do nothing for this acceleration. The first consideration is whether you are expecting more than the SD can truly deliver. I would respectfully suggest that you measure the acceleration time on the SD from 0 to 2200 rpm in first gear and report back. If the time seems excessive I can certainly do a comparison with my SD to confirm if you truly have a mechanical problem, or, if your expectations of the acceleration are a bit too great.

If we confirm that the 300DD is too slow from 0 to 2200 rpm, then, and only then, should we begin to look for a mechanical problem. In this case, and before adjusting the ALDA, it is imperative to ensure that your valves are properly adjusted and that the timing for the fuel delivery is correct. You must be sure that your mechanic has checked both of these items and that he has sufficient knowledge to properly check these items. Once they are correct, then he must check for a stretched timing chain. If the valves are operating later than they should be, then the performance will suffer. After all of this has been completed, then, and only then, should an ALDA tweak be considered.

First; Thanks for all the helpful tips. I'm not really sure which suggested corrective action really did the trick, but the old eighty duce is back in fine style.

When we were checking all the items mentioned in the thread, we cracked open the lines from the injector pump to the injectors; 4 of 5 worked great. The 5th wasn't even dribbling !

We pulled all the lines, cleaned everything, and the rest, as they say, is history.

Now for the next challenge: Body work