300sdl boost adjustment

[AMGmercedes]

Hello,
I was curious if the boost is adjustable on a 1987 300sdl. I have read many posts about adjusting the ALDA and then the boost on the earlier 5-cyl diesls with good results and wonder if the 6-cyl would respond similarly. I looked at the instructions for the 5-cyl adjustment and the 6-cyl is a bit different. For one there does not appear to be an adjustment screw for the wastegate under the spring, it appears to just have a spring(mine had a yellow strip on it, maybe there are differnt tensions for differnt pressures). Im assuming that the values stated for the 5-cyl regarding max spec boost(0.9-1 bar under full load at 4000rpm, with overboost curcuit kicking in at 1.1 bar) apply to the 6-cyl as well. Also I take it that the ALDA unit is adjustable like in the 5-cyl as well. I will test boost as soon as I get my hands on a gauge. The car isnt too fast on the highway, almost 240d accelaration with pedal floored, but around town its not too bad, seems to have good pull from ~2500 to ~3100 then not much power, and this only in the first 2 gears. Timing chain was changed 20k ago and pump timing was checked, and all filters and fluids were changed, with car having ~230k now. No smoke upon "flooring" leads me to believe the car is running a bit lean and/or turbo is going. Im assuming its the lean situation since the turbo spools up fine and pulls well for a little bit. The trap oxidizer was replaced with the straight pipe fix at ~150 along with the turbo. Any comments or suggestions are welcome.

[Mark Herzig]

I have my '87 300SDL (118,000 miles) in the shop and they are addressing a similiar performance problem. I don't have all the details but there is a vacuum that was clogged with oil causing sub-par acceleration highly noticable in the 40+ mph range. I am having this replaced and will report back with more specifics and feedback on improvements.

Boost on the '86-'87 300SDL is not adjustable. The amount of boost is determined via an engine load sensor which, when activated, decreases the amount of fuel delivered to the engine, thereby reducing power.

[Benzmac]

The boost will not increase the performance of this engine, all you have to do is turn a little more fuel to it by shimming the anaroid valve. If you have to ask how, you should take it to a tech that knows how. Oh yeah be sure that the anaroid valve is getting the boost from the turbo/intake.

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Benzmac:
1981 280GE SWB
1987 16V
ASE CERTIFIED MASTER AUTO TECHNICIAN
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