Temp sender to cold start valve, any way to test?
 

72 450 SL OK the two pole sender on top of the engine, any way to test to tell if it os working> I would just replace but it is pricy. I am in the process of renewing all rubber and senders, but this one is high.
I suspect it is fine, how would I know?

This is actually a Thermo-time switch rather than just a temperature sensor, so it turns on the CSV for a longer period if the engine temp is colder. To test it remove the CSV connected and put it on a voltmeter, pull the HT lead and connect it to ground. Now crank the engine for 10 seconds while watching the meter. It should show voltage for a few seconds, the duration gets longer the colder the engine is.

Thanks Gary, but what is the "HT" lead you refer to?
And I am pulling off the CSV connection and testing for voltage from the timer correct?

Hi,

HT - High Tension, its the high voltage lead that runs from the centre of the coil to the distibutor. Unplug it from the distributor and connect it to earth to stop the car starting. Alternatively you can disconnect the connector from the trigger points for the same result, its a big connector block on the left of the distributor with a wire that goes down to the lower part of the distributor.
Yes, if the CSV is turned on for a short time after start a cold engine then the thermo-time switch is working.