Honda is sticking by its decision not to employ outside help from rival engine manufacturers to help rectify the issues it faced with its power unit on its return to F1 last year.

Honda struggled throughout 2015 with poor reliability and a lack of power, leaving McLaren struggling at the back of the grid throughout the season. Honda motorsport boss Yasuhisa Arai admits his team struggled to cope with the amount of issues it faced, but says it now understands the problems.

"Up until the Spanish Grand Prix in May, it was like playing whack-a-mole," Arai told Nikkei Asian Review. "As soon as we resolved one problem, another popped up. Though we don't disclose the number of people involved in our F1 team, about half of them are new to the field.

"The biggest challenge involved technologies for the system to recycle heat energy and convert it into electricity for use to assist motors. At the summer Belgian and Italian Grand Prix events, called 'power circuits' because they involve long straight runs, we recognized we could not catch up with other teams.

"Even if we increased the power output of our engine, it would lose some 160 horsepower on straightaways due to the shortage of heat energy. We needed to carry out a complete review of the basic hardware design, but we couldn't do that during the season.

"In the second half of the season, we tried other approaches to improve our performance as much as possible. But we had a tough time. Honda faced the same problems that other teams did after F1 rules were changed in 2014."

Despite its struggles, Honda refused to recruit experienced engineers from other teams, even when it was advised to do so by McLaren.

"We thoroughly discuss problems [with McLaren] until we see eye to eye," Arai explained. "The talks are neither cosy nor confrontational. Sometime around last summer, they asked if we had sufficient [development] resources and wanted to know why we were doing things exclusively on our own. They also asked us to use outside personnel, which from their perspective is natural given the high job mobility in Europe.

"But we explained that Honda has a different philosophy. It's important to nurture manpower. It isn't acceptable to us to have an outside engineer stay for just three months or half a year."

Arai is confident Honda will not see a repeat of its 2015 problems this year.

"We're keen to meet everyone's expectations and reach the podium as soon as possible. We will resolve the technological problems we failed to address in 2015 and will head into the opening race with confidence."