Speed Relay Problem with 123 Distributor

[sbarouch]

I’m hoping someone here can help me figure out why my speed relay is not responding to rpm data via the negative terminal connection to the coil.

Here’s the background: I have a 1971 280SL automatic; removed the transistor ignition components and replaced the original distributor with a 123 distributor. Connections to the new distributor is with red lead to the + coil and black lead to – coil. The original ballast resistors have been bypassed.  I removed the green wire that was originally coming from the 7 terminal on the transistorized component under the battery and going to the 4 pin on the speed relay.  I made a new connection from the – coil terminal to the 4 pin on the speed relay for the rpm data.  The rpm data on this connection has been verified with a tach meter.  It was suggested that a resistor is needed in this connection to reduce voltage to the speed relay so I installed a 38.5 ohm resistor in the wire.  The speed relay has been repaired and tested by Beckmann Technologies. The only emission component that has been disabled is the Stop Solenoid.
 
The problem is the two-way valve is not closing off the vacuum once rpm reaches 2400 and beyond thereby keeping the distributor retarded.  I have tested the both 100 deg and 17 deg switches and they do operate the two way valve so it appears the Relay Box (33) is working.  I haven’t tested the Transmission solenoid input to the Relay Box as I don’t see how this would affect the Speed Relay and besides I was getting the full timing advance out of the original distributor before replacing with the 123 distributor.

Any thoughts or suggestions would be appreciated.

[WRe]

Hi,
did you recognize this: https://www.sl113.org/wiki/Electrical/123Ignition
"Using the "123" with later W113's with Emission Control
The Emission System and all of its components must function to factory specs and the timing set to accordingly to those values. With the Emission System fully funtional, use "123" Curve setting "E".
If the Emission System is not functioning to factory specs, you need to change over to a different Throttle Body Vacuum pick up and change to a TDC Timing setting. With the elimination of all the Emission components, use "123" Curve setting "8"."
I would remove the whole Emission Control System.
...WRe

[sbarouch]

Thanks WRe, I did read that section and I do have the 123 distributor set accordingly.  The only emission item not connected is the fuel shutoff solenoid.  I'm not hopeful that will solve the problem but it's worth a try.