GP controller normal operation

[Angelo]

Having trouble with cold starts, but starts easy if block heater plugged in a couple hours(I had a couple other posts around this same issue but returning to testing today).

I realized the GP are not staying on for the whole WTS cycle, I test with ammeter on battery cable and it's 40a on and off a few times before end of WTS, I can hear the controller going on/off and it correlates to ammeter reading 40a/2a. Is that how the controller is supposed to work? I would think the GP should stay on the whole time in order to heat the block enough but I'm relatively new to diesel engines.

 

[smdk2500]

how long does you WTS light stay on? I don't think it is supposted to cycle like that it should stay on 10-15 seconds then off. Ive never checked mine while it does its thing. Almost sounds like a ground or power problem the the GP controller.
A suggestion you might check out this fourm https://www.dieselplace.com/forums/6-5l-diesel-engine.21/ There are some very knowledgeable people over there. Not to say anything bad about the people here but over there they are more specialized so to say on the 6.5

 

[Schurkey]

Don't you already have two previous threads on this exact same topic?

https://www.gmt400.com/threads/hard...s-when-measuring-with-clamp-on-ammeter.51376/

https://www.gmt400.com/threads/hard-start-when-cold.51433/

 

[Angelo]

Well, this issue was more exaggerated by the colder temps we just had, it was not starting at all, only crank. When it'd start 1/20 tries randomly, it'd be smokey and no response from pedal for much longer than before. So I posted this at dieselplace finally.

Someone said to try bypassing the PMD extension harness. That made the difference! It'd start easy by connecting the PMD directly without extension. And I'd try with the ext. harness and no start. Tried a few different times and concluded it's the ext. harness. Started this morning first try with plenty of pedal response which hasn't been the case in a while.. Anyone reading this in the future, try w/o PMD ext. harness