Yeah, I agree. But why does it start right up in the morning? Would the air bleed out overnight? And if so, why?

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Heat can play a big role when you're dealing with air in the system. The IP gets quite hot when the engine is running (which is why the fuel heater is kinda pointless unless you live in Siberia) and any air that's in there will expand and displace fuel. Air is lighter than diesel, so it tends to collect up at the top of the fuel rail and any high points in the system when the engine shuts off (the air tends to be in a foam when the engine is running). When it's hot and expanded, it displaces more fuel, you start trying to pump that through the system and you get temporarily air bound. Wait overnight and the air either burps out of the system, or contracts to the point that diesel largely fills the voids and voila - easy starting. Obviously if you have massive air leaks you'll simply air up the system and always have hard starting, but small leaks can cause weird issues.

K-Jet gas engines have a similar problem due to vapor-lock. They have a spring-loaded pressure accumulator in the fuel system to try to keep the fuel system under pressure to minimize hard starting from vapor lock. Different reasons and mechanics, but similar concept and issues.

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Current stable:
1995 E320 157K (Nancy)
1983 500SL 125K (SLoL)

Gone but not forgotten:
1986 300SDL (RIP)
1991 350SD
1991 560SEL
1990 560SEL
1986 500SEL Euro (Rusted to nothing at 47K!)

Gone and wanting to forget:
1985 524TD 167K (TotalDumpster™) [Definitely NOT a Benz]

When you install that IP make sure you have an intercooler. All that extra fuel and heat without more air is going to raise your EGTs and could kill your bottom end. I'm not sure of where to mount those either short of taking out the AC condenser.

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Only diesels in this driveway.
2005 E320 CDI 243k Black/Black
2008 Chevy 3500HD Duramax 340k
2004 Chevy 2500HD Duramax 220k

Plan is for more air and a pyrometer at a minimum.

An intercooler is tough, because as you say, there really isn't anyplace to put one (at least of a decent size), and also because I don't have the fabrication skills necessary to alter the intake manifold and everything else.

Anyway, my local geography affects my driving style quite a bit - we're on an island in the PNW with nothing larger than a 2-lane road. I don't regularly exceed 60mph (well, at least not in this car ) and there are no hills to speak of. So, in the beginning at least, the plan is to keep an eye on EGTs and see what my actual needs are in terms of intercooling.

Worst case scenario is it's too hot and I have to turn the fueling on the pump down.

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