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#1
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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 |
#2
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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.
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#3
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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 |
#4
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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.
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'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 |
#5
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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. |
#6
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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 |
#7
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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
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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! |
#8
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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). |
#9
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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.
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#10
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Thanks for all the input. After trying all of the suggestions I think it is time for a new timing chain.
Thanks Ulf |
#11
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No effect from ALDA adjust?
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