Poor visibility, however, meant that Hulkenberg completed just one installation lap in the Toyota-powered car before the session had to be suspended. The team are hoping to be able to continue work later in the day, assuming conditions improve.
Renault are also expected to debut their 2008 car, the R28, on Monday. Again, though, the weather is likely to dictate whether Fernando Alonso gets the opportunity to try out his new machine.
Williams and Renault will be joined at Valencia by the rest of the Formula One teams from Tuesday, with testing scheduled to continue until the end of Thursday.
