I just bought a used 2000 Ram 2500 CTD. The previous owner was an elderly man who pulled a camper some with it. It's got 191k miles on it now. At 180k miles he replaced the tank fuel pump as well as a lift pump. Both were dealer installs with receipts with mileage etc. The truck has every single thing he's ever had done to it. So I feel comfortable about the work being honest work. Anyway. I pulled my 24' trailer and Cuda home from SC where I got the truck. It was cooler that day and I left it running mostly. So I guess I didn't notice it. But after driving it here the last week or so, I've noticed hard hot starts. In the morning, be it 30 or 80 degrees, it jumps right to life. Extremely fast cold starts. If I drive it, get it up to temp, stop and go in a store, fuel , etc... I'm on the starter maybe 2-3 seconds and it fires. It doesn't stumble to life, it comes to life pretty snappy. It just takes an embarrassing 2-4 seconds of cranking. I've tried touching the throttle to wide open just trying to diagnose it. Of course it's never fired wide open, I have more mechanic sympathy than that. But during that long cranking processi tried various throttle position. It has never NOT cranked hot, just takes a few seconds.
I read all kinds of " oh your VP-44 pump is out, get ready to drop $1500" all over various searches. Could it be something simpler?
Also, please note, if it's been running a while, and I shut it off.... It will fire right back up. Seems the hard to starts are after it has sat for 5 minutes up to even 1 hour tonight at dinner. Thoughts? Thanks!!!!

Do you have a fuel pressure gauge? Could be an issue with the return line and losing fuel pressure, maybe the check valve that's in the return banjo on the vp44. It could also be the o-rings in the tubes that go to the injectors... to me it sounds like a fuel pressure problem and loses pressure when it sits.

Usually hot hard start/rough idle are pump related. Pump wear (from use)opens the clearances in the pump resulting in internal leaking. premature wear has been attributed to the Low Sulfur fuels we are using.

Fuel pressure how much? Codes?

I had a 2002 CTD and did all the maintenace after I got it from the PO including the VP44 replacement. You can get the codes from the computer without a code reader. Check the Cummins turbo web sites for how to do it and a list of the codes. Basically it involves turning the ignition key to the on position, then off, them on again a few times w/o starting. Codes are displayed in the odometer window. You can't clear them only display them. Good luck, I wish I still had that truck.

I have been seeing this issue more and more with vp44 equipped trucks as of late. The problem seems to be the fuel itself that is the culprit. If you had a fuel drain back problem the engine would not start easily cold either. You would also have a long crank time and most likely run rough for a few seconds and possibly some smoke. I have been suggesting to my customers to add a pint or so of 2 cycle oil to a tank of fuel to help with this issue.

I've seen a crank or cam sensor do this after "hot soak". It usually sets a code....but I had a crank sensor that didn't. I've also seen vp 44's do it. I had a customer that used a trans fluid funnel and would dump a gallon of water on his pump to get the truck to started in the heat of the summer out here. Finally had the pump replaced and all was good.