Thanks for the suggestion.
Ironically I was just talking to someone about trying that exact test. I am going to try it.

That sounds exactly like my symptoms.

I have a Cascade overflow valve for it. I think that is one of the only serviceable items on the CP3. That and maybe pulling the high pressure connector with that ball and spring that wants to fall out and check it out.

 

That suggestion was DEAD ON!
Got home from work.
30 minutes later, tried a restart, got a really bad crank time.
I got the garden hose, and poured water over the CP3 for 60 seconds or more.
Immediately got a good start.

Couple hours later, I put in the last new part I had, a cascade overflow valve.
$39 or so.
Did a quick restart, and now (while cold) it seems like the shortest crank time i have had in years.

Nothing visibly wrong with the old one.
From research, this device meters return flow from the cp3, and also maintains pressure between the gear pump and the high pressure pistons. Makes sense that it could be a root cause device.

I will report back when after I have truly demonstrated if there is any fix.(need to get it hot on a hot day).

THANKS!
Chris,

 

Finally got the truck hot on Sunday.
Still has the problem.
Pretty sure i just need a new injection pump at this point, but I am going to do the injector return test first.

Anybody have a favorite place to order injection pumps from?

 

Ran 2 more tests today.

1st, got the truck hot, recreated the long crank symptoms, then disconnected the FCA and tried cranking again.
There was no change to starting performance.... did this to eliminate any possible electrical or computer problem.

Next,
i finally got the return flow test fitting 9012.
At idle:
Injectors return 75 mL/min.
Pump returns 780 mL/min.
Both at idle.
The specs I found are 160mL/min for the injectors and 1000 mL/min for the Injection pump.

More info, an online buddy at cummins forums just solved the identical symptoms with a new injection pump.

Looks like I am ordering an injection pump tomorrow.

Leaning towards a fleece CP3K from Diesel Power Products. (I just dont want to risk anything on remanufactured crap).

Any thoughts? Particularly on those return flows?

Thanks!

 

Replaced the injection pump on Saturday.
That fixed the problem.

I used a Fleece CP3K.