I'm going nuts trying to figure out how to hook up the vacuum lines going to the transmission. The car shifts alright, but it's rough. I think I can get it better, though I'm pretty confused by all the modulators, orifices and switchover valves.

The car is an '81 240D with a 5 cylinder motor from an older '79 300D non-turbo. The transmission is an automatic from the 240. The transmission doesn't have any linkages going to it, only a single vacuum line that goes to the modulator. The vacuum pump pulls a solid 20" of vacuum. My current setup is this:

Booster Line -> White Piston Duder on The valve Cover -> Transmission

It drops the vacuum from 20" to 0" when I push on the accelerator. I believe it should start out more at 15", but I'm not sure how to make it do that. Do I need restrictive orifices for that?

Also, what's the bell housing thing on the top of my injection pump? It has a hose barb on there, but it doesn't seem to do anything. I think this should be an ALDA if this was a turbo motor, but it isn't. What's the deal?


Vacuum Modulator by Christian Bryan, on Flickr


Mystery Component by Christian Bryan, on Flickr

the bell is an ADA, take the vacuum line off of it. it's supposed to be open to sense atmospheric pressure.

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John HAUL AWAY, OR CRUSHED CARS!!! HELP ME keep the cars out of the crusher! A/C Thread
"as I ride with my a/c on... I have fond memories of sweaty oily saturdays and spewing R12 into the air. THANKS for all you do!

My drivers:
1987 190D 2.5Turbo
1987 190D 2.5Turbo
1987 190D 2.5-5SPEED!!!

1987 300TD
1987 300TD
1994GMC 2500 6.5Turbo truck... I had to put the ladder somewhere!

Ah, good to know. I suppose the ADA varies the fuel mixture for different altitudes then?