Is it possible o have an alda leak vacuum?
I opened it added a ring and after closing it i still see a few bits of thread, like it didnt close all the way,i now have gone thru the entire diagram on the car and all is tight exept there, i do have clunks and hard shifting that i never had before.

1987 300d w124

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W123 1985 300TD naturally aspirated

The ALDA isn't linked to the vacuum system. You must have knocked loose another line.

There's a line from the ALDA to a VSV by the transmission vacuum amp. Above engine temp of 50*C, the VSV directs boost to the vacuum amp to modulate shifts. Below 50*C the VSV directs vacuum to the vacuum amp to soften cold shifts.

Sixto
87 300D

my sd has a vac modulator on the ip pump.it was leaking at the top making buzzing sound. i carefully painted it with silicone,works better.

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1999 w140, quit voting to old, and to old to fight, a god damned veteran

But there is a vacuum line going to the top of the alda.

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W123 1985 300TD naturally aspirated

That is a manifold pressure line. If you trace that line back, it will go to your overboost protection valve, then continue on to the banjo bolt on your intake manifold. That line carries pressure from the manifold to the ALDA, which reduces its fuel restriction with increased pressure.

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On some nights I still believe that a car with the fuel gauge on empty can run about fifty more miles if you have the right music very loud on the radio. - HST

1983 300SD - 305000
1984 Toyota Landcruiser - 190000
1994 GMC Jimmy - 203000

https://media.giphy.com/media/X3nnss8PAj5aU/giphy.gif

For clarification:

The vacuum that operates all of the ACC, shifting, shutoff, etc. functions in the 124 is from an engine-driven vacuum pump.

The line to the alda, is not connected to that system, only to the intake.

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Gone to the dark side

- Jeff

By altering the ALDA setting you also alter the normal throttle position required to accelerate.

Adding a ring (reducing off-boost fueling) takes more throttle to accelerate so the VCV sends a lower vacuum signal to the transmission which makes it shift harder.

But is it possible to add a ring and have smooth shifting? Is there a tutorial?
Thanks

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W123 1985 300TD naturally aspirated

Adding/subtracting shims is only necessary if adjustment is necessary beyond the adjustment of the screw. Further, if the adjustment (whether shims or screw) is to compensate for wear, it should restore proper shifting from hard-shifting (such is my experience) as the pedal will be down less for the same power output.

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Gone to the dark side

- Jeff

How much vacuum do you get out of the VCV while idling? I had hard shifts that turned out to be a bad VCV.

Sixto
87 300D

Hey this thread is good info for me. Where the heck is this VCV?

Any pictures or good explanations?



Edit: Ok located the VCV. During one of my car's strage shifting episodes. I popped the hood and i could hear a whining sound coming from the VCV box.


The car does ok other than the slightly rough 2-3 shift. But recently it's started dragging the 3-4 shift out to almost 3,500 RPM sometimes higher. It doesn't want to shift past 3rd unless i've noticed i pop the gear shifter up into neutral for a few seconds then engage drive again and the problems seem to go away.

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93 300 D 2.5 turbo

Bad Vac Control Valve?
http://www.peachparts.com/shopforum/diesel-discussion/117168-bad-vac-control-valve.html#post834716

Vacuum Control Valve
http://www.peachparts.com/shopforum/diesel-discussion/121418-vacuum-control-valve.html#post869411

What does the vacuum control valve actually do?
http://www.peachparts.com/shopforum/diesel-discussion/195783-what-does-vacuum-control-valve-actually-do.html#post1578883