1968 280sl cold start problem

[fmccaffr]

I have had a 1968 280 SL for 25+ years and have had the cold start problem as long as I can remember and have not discovered a satisfactory way around it. I do not used the car in the winter so it is not a serious problem but I feel that I may wear out the starter if I don't do something about it. I really don't know where to start but I do know that some of the related wires are not connected based on looking in the service manual. Any suggestion would helpful. I am also going to Germany Aug 4 and plan to buy some parts while I am there. Thanks

[ja17]

Hello,
There are several cold starting aids on this M130 engine. They vary depending on the year of manufacture.
The first item to check is the cold start solenoid valve on the intake manifold. The device is on the end of the intake manifold right above the shock absorber top. It has one wire going to it, a small metal fuel line and a large metal air line. Check its function with a test light. The wire should be hot during cold starting (below 35 deg. C), activating the valve and squirting extra fuel for starting into the engine. The duration of this depends on how cold the engine is.
In addition if your injection pump is the R19 version or before it has a solenoid on the back of the pump to assist in cold starting. If your injection pump has two solenoids, only the top one is used for cold starting. Use a test light to check it also. It should activate as long as the starter is engaged. Injection pumps R22Y or R24Y do not have the starting solenoid.
If you find one of these devices not functioning we can troubleshoot the cause. These starting mechanisms are controled by a temperature sensor, and time relays. Let us know what you find.

Joe Alexander

[Tom Hanson]

In addition to Joe's comments, if your cold start valve ends up being the culprit, you can replace just the electrical solenoid portion of it (contrary to popular belief). Keep us posted. Parts may not be any less expensive in Germany either.