Honda chief Yusuke Hasegawa says that reliability gains seen on the manufacturer’s dyno are not being replicated on-track, which is a new problem for 2017.
Relations between McLaren and power unit supplier Honda have been increasingly strained this season, its third campaign since reuniting, amid a lack of reliability and performance.
Honda had hoped to introduce an upgrade package at last weekend’s Canadian Grand Prix but this was delayed, and Hasegawa was unable to give assurances that it would be ready for upcoming rounds in Azerbaijan and Austria.
Hasegawa explained that Honda is struggling to transfer results seen on the dyno to the circuit, a situation it did not encounter in 2016.
“We can't create good conditions on the dyno," Hasegawa told Autosport.
"We need to create the same conditions from the track on the dyno.
"The operational conditions are different so we need to understand why that makes a difference to the reliability.
"Last year, we could prove engine reliability on the dyno so we need to understand why now there is some difference from dyno to the circuit running [and] it's not easy. We need to improve the accuracy.”
McLaren has yet to score a point this season, with its cars reaching the chequered flag only four times from 14 starts, taking a best result of 12th in Spain, courtesy of Fernando Alonso.
Alonso retired from 10th place during the closing stages of last weekend’s Canadian Grand Prix due to a loss in oil pressure, while Stoffel Vandoorne came home in 14th spot.