A while back my 92 W-250 began smoking (white) badly at start up in cold wheather. Seems to have begun somewhat abruptly.
Is it possible this is the cold start soleniod and if so is there an easy way to test it and a better (less expensive) place than the local dealer to buy one?
Thanks.

 

Check the solenoid by pulling the wire off while it is cold. The engine should slow down a little. If it doesn't and your wire connection is good and tight then you may need it changed. It is a bosch part but I don't know the number.

 

Check for power at the solenoid (test light is fine) when the intake temp is below 90 degrees. Key on, engine off. If you have power, do like Boatnik said and pull the wire off. If the truck doesn't run any different, the solenoid is bad. If there's no power (more likely), check to make sure that there are two wires plugged in at the shutdown solenoid. If that's good, check for power on both sides of the KSB switch (on top of the intake manifold close to the firewall). You should have power through that switch when the manifold temp is below 90 degrees.