McLaren has successfully fired up its new Renault-powered MCL33 for the first time at its Woking factory.
Following a switch from Honda engines, McLaren had to play catch up late last year to accommodate the new concept of power unit in its car.
Ahead of an official launch next week, the team released a short video of the Renault fire-up on Friday.
However, with the team expected to reveal a dramatically different livery for 2018, the clip did not offer any clues about the car's new look.
McLaren is bullish about its switch of engine partners and the team said recently it had been encouraged by its initial working relationship with Renault.
Chief engineering officer Matt Morris said: "I think the big difference, speaking with all the guys at Renault, is they have got more experience.
"Those guys on the ground have been doing it for a lot longer than Honda, that is just a fact, and that is what allowed us to get the packaging done so quickly.
"It is just their experience and the same is true in their factory at Viry. It is more mature than Honda. It might not have as many fancy dynos, but they just have more experience."