Toro Rosso's Pierre Gasly was unable to take part in qualifying for the Mexican Grand Prix.
The Frenchman had already missed out on final practice. He was forced to park the car after a puff of smoke from his engine on his installation lap.
The team investigated the issue over lunch and found that the STR12 needed a new MGU-H fitted. Gasly initially joined the team members on the pit wall watching his team mate Brendon Hartly taking part in the session.
However he was called back to the garage and told to suit up in the hope that the engineers would complete the engine change in time to allow him to go out in Q1.
A few minutes later he was stood down again, as time ran out on the team's efforts to get the car track-ready.
Meanwhile Hartley made it through to Q2, only to then suffer a loss of power from his own Renault engine. It strongly suggests that there will more issues for the team to address overnight, and possibly grid penalties for Hartley as well.
Gasly had already incurred a five-place grid penalty for Sunday due to a change to his Control Electronics unit on Friday. The latest issue means he will be hit with a further 10 place drop.
As a result, Gasly will be starting at or near the back of the grid for the race. The two McLarens of Fernando Alonso and Stoffel Vandoorne also face hefty grid penalties this weekend.
Despite a near-brand new engine, Alonso reported a brief loss of power on his MCL32 in qualifying. However the car seemed to recover and Alonso later said that the car felt "great".