"He had a funny feeling with the car," said team boss Eric Boullier, defending Alonso.
But Honda's Yusuke Hasegawa said: "We could not find anything wrong in the data."
It is a complex situation.
Auto Motor und Sport explained that if McLaren dumps Honda, it would be a simple breach of contract but with no consequences.
But if McLaren nudges Honda into quitting the deal, that would involve millions in compensation for the British team.
"In what world do they live?" Red Bull's Dr Helmut Marko wondered. "If you get rid of someone, you don't also get money."
So at the moment it appears to be a situation of stalemate, with McLaren waiting for Honda to make a decision -- and vice versa.
Alonso is now making clear what he thinks should happen, particularly as his best alternative for 2018 appears to be a move to Williams-Mercedes.
Boullier said: "With a Mercedes engine, we would be two seconds faster than Williams."
Alonso said of the McLaren situation: "There has to be a change.
"I think there are answers out there but we have to find them -- and they won't come from looking at the sky," he is quoted by Spain's El Mundo Deportivo.
"We have to sit down and work and hope to find the best solution for next year."