Jenson Button may have to wait for Honda's upgraded engine for at least another race as the manufacturer investigates Fernando Alonso's engine problems from Austin.
Alonso was running the new spec Honda engine at the U.S. Grand Prix and looked to be on for a top-six finish before he suffered a sudden loss of power in the final stages. Though he finished the race Alonso later revealed the loss of power cost him 30 seconds in the final 12 laps, with Daniel Ricciardo beating him to the final points-scoring position on the final lap.
After the race Honda revealed it is launching an investigation into Alonso's power unit. A limit on manufacturing time meant Honda could only introduce the new power unit on one car, with Button's originally due for this weekend's Mexican Grand Prix.
However, McLaren racing director Eric Boullier admits this is far from a certainty now.
"We need the investigation on the engine before we decide because we need the engine to last longer than this," he said. "Fernando lost power, but we don't know exactly why yet. We understand that there was an issue with some sensors maybe, so we had to tell him to reprogram differently the car, but the damage was done."
Alonso also believed the problem had been caused by an electrical issue and said it had cost him a good finish in "one of the best races" of his life. Honda chief Yasuhisa Arai said that the upgrade "performed to our expectations" throughout the weekend before Alonso's late problems.