Scottladdy, I wanted to explain why I cycle my glow plugs the way I described earlier. When I bought my 1028, it only had the manual glow plug button. When I turn the key on I have no wait light or controller telling me when to start the truck. This being my first cucv, I am at the mercy of this valuable forum for info on my truck and tips and tricks to proper operation. I have done as much research as I can on the glow plugs and their operation. I don't know how long is too long to let them glow before they swell and fail. This is a big fear of mine. Not knowing any better I cycle the plugs for ten secs as to not over work them. I watched the excellent video of the theory of operation of the glow plugs sticky and see that the controller does keep them lit for awhile. I tried to count how long they stay lit before they go out then cycle the after glow( three sec on three off). I try to mimic what the controller should be doing if it worked. If anyone could explain what the glow plugs are capable of so the guys with manual buttons operate the system the way it should work without overworking the plugs or wasting time cycling them; it would be greatly welcomed.
Well, unfortunately part of the answer lies in what type of plug you are using. Older style non self regulating plugs need more care. Newer style self regulating plugs like the AC60g's actually reduce the current demand as they heat up in order to extend their useful life.
With AC60g's, my cold start wait light times range from 5 seconds in August to 18 seconds in 0F temps. But I do believe the GP controller behavior is different with self regulating plugs as the current draw reduces as these plugs heat up. As such, your mileage may vary.
From this article:
http://www.accuratediesel.com/gplugs.htm
"If your vehicle starts OK if you plug in the block heater overnight, but will not start if you do not, then you probably have a glowplug issue unless your engine has very low compression."
Apologies for not being more specific, but hopefully you understand why. My advice would be to start by trying to identify the type of plug installed. If they are a self regulating variety then I see no harm in keeping them energized for 18 seconds in below freezing temps. If they are not, you might consider installing a set to increase your peace of mind.
So glad you are able to find useful information on this site. I am still attempting (feebly) to repay the value I have received myself.
One last thing. I have many friends who have diesel powered power and farm equipment equipped with glow plugs. None of their equipment has a wait light. When they hitch a ride from me, every one of them has mentioned how nice it would be to have a wait light to tell them if the plugs have been energized long enough. None of their equipment has such a feature.