Gents and Ladies,
My CSV has not worked at all in the seven years I have owned the car. I finally decided to get to the bottom of the problem. I'll try and keep this brief and consise.
Hook a test lamp up the the lug on the cold start valve and ground. If the lamp lights while the starter is engaged your CSV relay is working. In my case the lamp did not light. Therefore the cold start valve solenoid was not activated to enable the CSV jets to spray fuel into the intake manifold. I traced all of the wiring on the CSV relay connector and it all checked out. So the relay was the problem. If you suspect the relay there is a very simple test to perform to check out its functionality. Remove the relay from the car. Hook up a ohm meter to pins 87 and 30 of the relay. Apply 12 volts to pins 86 and 85. You should hear a click and the ohm meter should show 0 resistance. If the ohm meter does not show 0 you have a problem with the relay. I carefully bent back the 6 crimps on the bottom of the relay so that I could take the aluminum cover off. In my case the contacts were fouled.
Download Attachment: 
Cold Start Relay 1.jpg44.11 KB
The contacts are just like a set of ignition points. I used a piece of very fine emery paper to clean both contacts and then placed the ohm meter leads on pins 87 and 30 of the relay and applied 12 volts to pins 86 and 85. This time you should see the solonoid close and the points complete the circuit for pins 87 and 30 which now show 0 resistance.
I carefully reassembled the relay cover and bent the six sections of the cover over the relay base and installed the relay. I reconnected the relay to its connector and then connected the test lamp to the CSV valve lug and ground and started the car. While the starter was engaged the test lamp was on. As soon as the car started and the starter was disengaged the test lamp went out. I had previously disassembled and cleaned and checked out the CSV so I know it was working properly. The fix was simple for my problem and the car starts immediately. I can hardly believe it.
If anyone has questions please let me know. I hope the picture comes through, I've had problems posting them in the past and I don't know why.
Anyway best of luck.
Jeff
1970 280SL 4 speed
