Honda engine chief Yusuke Hasegawa has expressed his regret with how the first winter test in Barcelona has started for McLaren.
The MCL32 required two power unit changes in the first couple of days at the Circuit de Catalunya, which lead to rumours on Wednesday that McLaren were considering a split from their engine suppliers after years of unreliability.
Those rumours were quickly quashed by both parties, but Hasegawa did say he can understand McLaren's frustration.
"Obviously we are not happy to have trouble, but this is a test – and we are feeling sorry for both drivers," said Hasegawa. "So, we need to find out what has happened in the day two engine especially."
"We didn't know the exact cause of the problem of [Tuesday's] engine, but so far we didn't change anything.
"Because we don't know the cause of the problem we can't tell [what progress will be like] but I believe we can of course solve the issue before Melbourne."
Hasegawa was also asked what engine spec Honda were hoping to run at the second test next week.
He added: "It depends on what was the problem of yesterday's one was, but we are supposed to introduce the same spec engine for Melbourne [that we will run] next week of course."
McLaren were out of the blocks early on the final day of the first test in Barcelona, with the morning dedicated to wet weather simulation.
— McLaren (@McLarenF1) March 2, 2017