Parts Catalog Accessories Catalog How To Articles Tech Forums
Call Pelican Parts at 888-280-7799
Shopping Cart Cart | Project List | Order Status | Help



Go Back   PeachParts Mercedes-Benz Forum > Mercedes-Benz Tech Information and Support > Diesel Discussion

Reply
 
LinkBack Thread Tools Display Modes
  #1  
Old 08-05-2002, 11:54 PM
Ulf126
Guest
 
Posts: n/a
300SD no acceleration from a stop

Hi, I need some help. My 82 300SD with 255000 miles has NO acceleration/power off the line. It has been noticeable for about 6 months but has really gotten worse the last month or so. The valves are adjusted properly, air filter clean, fuel and oil filters are 3 months old and changed often. There is no fuel dripping out of the system. Only occasional light moisture, not enough to drip, at the #3 fuel line on the pump. I have light black smoke at startup and at cruise speed. It smokes real good when the rpm's go above ~4500 when shifting. It runs ok at cruise speed anything above ~2300 rpm, turbo kick-in speed. I have also been having a harder time starting in cold weather. The glow system works. Starts ok in warm weather. The acceleration problem only gets a little better after the engine warm-up. I checked the vacuum lines they look intact and all of the throttle linkages look good. The timing chain is original but appears in good condition. I have never messed with the pump timing. The factory or a dealer put an alignment mark on it and it stills linesup. The problem is accelerating from a stop. Full throttle, AC off and shift into low you would swear you could push the car faster the first two car lengths. Once it finally gets rolling it accelerates ok and even has the nerve to occasionally chirp the new tires as it shift into second gear. I hope I gave you enough info to help make a diagnosis that will graduate me out of the turtle drag racing category.

Any help greatly appreciated.

Thanks

Ulf

Reply With Quote
  #2  
Old 08-06-2002, 12:10 AM
Diesel Power
Guest
 
Posts: n/a
Negating any possible engine problem, have you looked into the trans. How is the fluid level? When was it last serviced? Does it sound like it's slipping? It sounds to me as if it is having trouble building enough fluid pressure to move the car.
Reply With Quote
  #3  
Old 08-06-2002, 12:41 AM
Ulf126
Guest
 
Posts: n/a
Trans seems ok

Thanks for the reply. The Trans is serviced about 1 to 2 times a year with new fluid including torque converter and filter. The fluid level is always near the upper make. Checked when the Trans is hot engine running on level ground after using all of the gears. It doesn’t sound like the Trans is slipping the motor just has no power until it builds up some rev’s. It takes about 30-40 yards to go from ~650 idle rpm to ~2300 rpm. The transmission is original and seems to shift ok. It makes no unusual noises.

The motor just doesn’t make the power needed.

Thanks

Ulf
Reply With Quote
  #4  
Old 08-06-2002, 12:28 PM
vwbuge's Avatar
Registered User
 
Join Date: Sep 2001
Location: Johnstown, Pennsylvania
Posts: 2,116
Ulf126,
I'm ready to put a years wage that I know what is wrong with your car. My '85 did the exact same thing. My mechanic and I learned of this from a post I put up about a year ago......There is a small round sleeve coming up from the top center of your injection pump. The inside part of this sleeve is a black rubber plug. Pry out the plug carefully and use a pair of cutters or something to gently tear away the sleeve. You'll find a set-screw with a lock nut. I will stop here because I can't remember if you turn the screw counter-clockwise or clockwise. I don't want to steer you in the wrong direction from here. I gradually turned this set screw and test drove after each adjustment. (1/4 turn at a time) My car came back to life!!!!!!!!!!!! I hope someone will chime in to tell you which way to turn. I don't really think it is your tranny or anything else.
__________________
'85 300SD (formerly california emissions)
'08 Chevy Tahoe
'93 Ducati 900 SS
'79 Kawasaki KZ 650
'86 Kawasaki KX 250
'88 Kawasaki KDX200
'71 Hodaka Ace 100
'72 Triumph T100R
Reply With Quote
  #5  
Old 08-06-2002, 03:04 PM
Old Deis
Guest
 
Posts: n/a
Before you mess with the ALDA, it would be much easier to first check the crossover valve. It is mounted on the cowl. There is a line coming from the rear of the intake manifold, around the back of the engine and into the crossover. Another line goes out from the crossover and leads into the ALDA.
This line and the crossover itself are susceptable to getting plugged up. Once plugged the ALDA will no longer increase fuel flow into the fuel injectors when the turbo winds up. Therefore no power at acceleration.
To clean I just removed the crossover and turned it upside down and sprayed carb cleaner into it until I could blow through the opening. You will have to get a 12 volt line to the crossover to get the thing to open up the waste gate. The purpose of the crossover to to limit the pressure coming through that line to something like 1.1 bars, or close. Anyway I had the same problem with my 81 SD and read the threads about the ALDA and found that to be the problem.
Just my .03 cents worth.
Reply With Quote
  #6  
Old 08-06-2002, 03:14 PM
vwbuge's Avatar
Registered User
 
Join Date: Sep 2001
Location: Johnstown, Pennsylvania
Posts: 2,116
sounds like a plan
__________________
'85 300SD (formerly california emissions)
'08 Chevy Tahoe
'93 Ducati 900 SS
'79 Kawasaki KZ 650
'86 Kawasaki KX 250
'88 Kawasaki KDX200
'71 Hodaka Ace 100
'72 Triumph T100R
Reply With Quote
  #7  
Old 08-06-2002, 07:12 PM
Registered User
 
Join Date: Aug 2001
Location: Evansville, Indiana
Posts: 8,150
Check the boost lines and the banjo bolt at the manifold, too, as they can all get plugged and cause a lack of added fuel.

It sounds, however, like you have adequate power once the turbo comes up, but not before.

It is time to check the chain for stretch -- it will look just fine until it gets so long it slaps on the highway and breaks a chain guide or get "overlapped" on a gear and breaks. A worn chain gives you both late injection timing and late valve timing, and late valve timing will give you very poor performance at low speeds. Smoke a high speed often indicates late injection timing.

If the chain is worn, replacing it will fix both timing problems with no other work!

The other thing to check is compression and leakdown -- you may be due for a valve job, or at worst, a rebuild.

Peter
__________________
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!
Reply With Quote
  #8  
Old 08-06-2002, 10:11 PM
mccan
Guest
 
Posts: n/a
The Banjo and attached line will not affect acceleration from a dead start. The ALDA adjustment is your best bet. It is a very easy and simple procedure (do a search). Jusy be VERY delicate when loosening the locknut and adjusting the screw. If the spring breaks or the screw snaps (both fairly common) you have to replace the entire unit.

The Banjo fitting and the attached hose allow the fuel pump to recognize the incresed pressure being supplied by the turbo and increase fuel flow accordingly. As the turbo is not contributing meaningful pressure below 2K, a clogged Banjo fitting or hose will not affect acceleration from a dead stop (as RPM is below 2K).
Reply With Quote
  #9  
Old 08-06-2002, 10:53 PM
Registered User
 
Join Date: Jan 2001
Location: California
Posts: 2,068
You could undo the banjo bolt from the ALDA unit and spray some carburetor cleaner inside. When I did, a whole bunch of black crud came out.
Reply With Quote
  #10  
Old 08-12-2002, 05:11 PM
Ulf126
Guest
 
Posts: n/a
Thanks for all the input. After trying all of the suggestions I think it is time for a new timing chain.

Thanks

Ulf
Reply With Quote
  #11  
Old 08-13-2002, 10:27 AM
mccan
Guest
 
Posts: n/a
No effect from ALDA adjust?

Reply With Quote
Reply

Bookmarks

Thread Tools
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is On
Trackbacks are On
Pingbacks are On
Refbacks are On




All times are GMT -4. The time now is 02:01 AM.


Powered by vBulletin® Version 3.8.7
Copyright ©2000 - 2024, vBulletin Solutions, Inc.
Search Engine Optimization by vBSEO 3.6.0
Copyright 2018 Pelican Parts, LLC - Posts may be archived for display on the Peach Parts or Pelican Parts Website -    DMCA Registered Agent Contact Page