As I understand it, my 1983 240D has an ADA, not an ALDA, on top of the injection pump. I know a little about ALDAs, really nothing about ADAs, so I thought I might pose a few questions. (There are a few threads on topic, but not a lot.)

1. How does ADA function differ from ALDA function?

2. At the base of the ADA there is a fitting that looks like it should have a vacuum hose connected to it, but nothing is there. What should I make of this?

3. Is it advisable to attempt to adjust the ADA?

4. If so, can I turn the set screw with the ADA in place or do I need to remove it?

Thanks.

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14 E250 Bluetec 4Matic "Sinclair", Palladium Silver on Black, 160k miles
06 E320 CDI "Rutherford", Black on Tan, 180k mi, Stage 1 tune, tuned TCU
91 300D "Otis", Smoke Silver on Tan, 145k mi, wastegate conversion, ALDA delete

19 Honda CR-V EX 79k mi
Fourteen other MB's owned and sold
1961 Very Tolerant Wife