"Timing Advance Mechanism" on IP: What is this?

[Couper]

Hi Guys,

I have been trying to get my 1984 300TD running for weeks. Please help me recover from another painful self inflected wound......

I just broke what I think is called the "Timing Advance Mechanism" on the Injection Pump on my '84 300TD. It's the square box that is attached to side of the IP with an attached wire that goes to the firewall. As I just found out, it is found only on the OM617 in 1984 and 1985.

Please help me with the following:

1. What does it do?

2. Can I get one at the junk yard without having to remove the IP?

3. Will an 1983 IP without a Timing Advance Mechanism work with on my 1984 w123? What needs to be done?

Thanks in advance. Any information is greatly appreciated as I'm really beating myself up for ripping out the wire from the box("TAM").