Had this new shape Picanto in for hard starting once the vehicle had ran for 5 minutes (or more) but then left to stand for 10 minutes. The longer it stood, the longer it took to start whilst cranking.

No fault codes present, nothing amiss with the electronics or sensors so I turned my attention to the fuel system, which in this case is returnless.

According to Kia it should run 46-52psi and hold after key-off for 5 minutes. This one didn't hold for 10 seconds, and dropped off to 0.5BAR (sorry for swopping between psi and BAR it was how I remember the figures). However it would start at just on 1.5BAR when priming, then run up to 4BAR.

The one factor I noticed is, on de-pressurising the system (unplugging the tank unit) the vehicle would not start at all.
After fitting the replacement pump and priming, the vehicle ran for over a minute unplugged!

Note: the fuel gauge takes 2-3 minutes to register the fuel quantity, so don't panic if it shows empty.

Fuel pump units (the whole tank unit inc fuel sender) is only £88+vat from Kia....