Hi-I have an 1985 300D turbo. The door locks went first, but the car would still shut off OK. Then the car started to take longer to shut off and then would only shut off by pushing the mechanical stop linkage under the hood. Then the car started to shift hard and had loss of power at times. I rebuilt the vacuum pump condersiding its age, but it did not help any. I used the search and did the following. I replaced the four way and the three way conntectors and all of the small rubber connectors. Here is what I found. There is a white vacuum valve I think it is called the vacuum control valve. It is mounted to the IP right above the shut off valve. It has two vac. lines the one on top has a green vac. damper valve and the line on the bottom had oil on the connector and a small black diam. hard vac. line that was not connected to anything and did not appear that it would of have gone through the firewall. Also I found a larger black diam. hard line at the same connector for the door locks and the HVAC broken. I believe that line goes to the reseroir tank. When replacing all the connectors the only oily one was the bottom conntector on the white vacuum control valve (?). Here are the tests that I performed. I isolated the large blk. vac. line from the pump to the brake boster connected a gauge and got a good steady 22 Hg. reading. I connected a vac. pump to the shutoff valve and the car shut right off. I also performed the same test at the ignition sw. and the car shut off OK. I isolated the yellow door lock lines & valve the green HVAC line the broken black line to the reseroir tank and the line going to the trans. mod. valve. Also isolated the white vacuum control valve (?) and the car would not shut off. Need some help please.
Thanks in advance.
Mike

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Mike