OK. Firstly, there are two cold start systems on your Injection Pump. One is the cold idle, this bumps the throttle up, and causes the truck to idle higher. The solinoid is not strong enough to overcome the return spring, so you should always pump your pedal once while your WTS light is on, to let it engage. The second system, is the cold start advance. This advances the timing on the IP while the engine is cold. There is a dramatic difference in the sound of the engine while this is engaged (provided it is timed close to correctly)
You should be able to see if the cold idle solenoid is working. Next time your truck is cold, before you start it. Turn the key on, and pop the hood. (do not pump the pedal) Then once under the hood, cycle the throttle by hand. You should see the plunger pop up on the solenoid when you do that.
As far as the cold advance. You need a meter to test for that. So let us assume it works for a moment. First, you need a pump wrench. You can make one out of a tight space wrench with a grinder (use the search button, there are many posts on that) Next, there are two connectors on the top of your IP, IIRC the once closest to the front of the engine is the cold advance. First, with a dog clip wire, make that hot. Then bump your IP towards the passenger side of the truck one dimes width at a time. (there should be marks on the IP and IP housing you will be able to use for reference) Tighten down and start the truck between each move (NEVER START THE TRUCK IF THE IP IS NOT TIGHTENED DOWN, YOU WILL DESTROY IT) You are listening for a pronounced rattle, it literally sounds "like a powerstroke." Personally it almost sets my teeth on edge. Once you get that sound, pull of the advance wire while it is running. It should settle down into that IDI rumble. If it does not, go back, you've advanced too far.
Honestly, timing it that way is a B!%@H, just rent a timing meter from Gary (icanfixall) He runs a timing meter rental program. Trust me, a meter takes ALL the headache out of timing.