Doesn't matter. 19psi is too much for anything the stock injection pump can supply. 15psi max is all the engine needs without an intercooler, 12psi with.
More boost than absolutely necessary increases exhaust pressure, especially above 4000rpm when the torque capsule is taking away fuel. The wastegate stays closed more to make the turbo spin faster.

Don't forget to post the year/model of your car. The original poster did neither. The OM61x (MW) pumps tend to be a lot lower on fuel delivery after 25+ years than the OM60x (M) pumps, for whatever reason. Measure boost pressure and clock the 0-60 performance with a stop watch, those will give you solid data to work with. If the car is significantly slower than factory spec, you should be able to get it back to spec with some tweaking.

:zorro:

The ALDA on my 85 CD is shot. IT's been turned up all the way (by PO) and the car will not even go 5 mph if you try and adjust it down. If anyone has a good one I could use it.

Can you remove the alda on the 85? I did on my 87, but not sure about the 85 and how you would go about it if you can.....

yes you can remove the alda on an 85. Large nut under it, turn it while holding the body to remove. think the nut is around an inch or so.

No, sorry, I meant remove it completely from the car, and alter the vac lines.

Sure, but you are just putting a band-aid over the real problem... your IP is too low on fuel delivery. But as a cheap/easy fix, it will help for a while. BTW, it's not likely your ALDA is defective; unless something is broken internally and jamming the capsules all the way down. Would be interesting to take it apart and see.

Actually, "the PO adjusted it and now the car won't go over 5 mph" sounds like exactly what happened when I turned the screw too far on mine. The screw shears off and then you have the slowest car in the world. I bet it's been broken internally by ham-fisted screwdriver work...just like I did to mine.

the large nut under it does remove it from the car. plug lines. In a perfect world you fix alda and any problems related to it. Must say just removing it works too. At least this will give you an idea of how it performs with out it. Then you can decide what to do next. I do think you should check fuel pressure if you have not already.

I filmed my 300CD after doing some IP tweaks. I still can't get much smoke if any...

• 14psi MAX w/ wastegate fully tightened
• ~1100F MAX temps on a LONG pull
• ALDA Removed
• Rack Limiter Removed
• Horizontal Throttle Stop turned in 1/2 turn

Mercedes 300CD Exhaust - YouTube

I read on another site, about removing banjo bolt and cleaning it with carb cleaner if its gunked up

my 1987 300 sdl, I cannot find the alda boost system. any help or thought sure would be appreciated

Intake plenum, small air hose about above the Cruise Control actuator, hose runs out to a valve (switchover valve) bottom fitting, back out of the middle fitting and over to the ALDA. No banjo bolt on this engine.