Autosport and RaceFans have reported:

McLaren has changed auxiliary components, including parts of the fuel system, on Lando Norris’s Mercedes power unit ahead of the Singapore Grand Prix. The team is aiming to resolve an intermittent fuel injection problem that reduced Norris’s straight-line speed in recent races. The fuel system is managed on McLaren’s side rather than by Mercedes, which supplies the engine.

The issue was identified at the Azerbaijan Grand Prix in Baku, two weeks ago, where McLaren was notably slower than Mercedes on the long straights. Some of the gap was attributed to weaknesses in the car and the way McLaren operated the Mercedes unit, but Norris’s car had a particular loss of top speed during qualifying. The problem returned intermittently in the race and affected Oscar Piastri’s car to a lesser extent.

It also hindered McLaren at last weekend’s Bahrain Grand Prix in Malaysia. Norris said he was hopeful the changes would help, but wanted to assess them in practice. “I need to get on track first and see how much better it is,” he said on Thursday.

Norris said the past two weekends had been frustrating as the team tried to identify the cause of the continuing performance loss. “It’s been a frustrating two weekends trying to figure out what the issue’s been and why there’s just been a constant lack of straight-line speed and performance,” he said. “Especially in this kind of battle we’ve been in, the last two qualifying [sessions] it’s been two or three positions. So it’s cost me quite a lot.”

He won in Hungary and the Netherlands and came close to winning in Madrid, taking pole position at all three rounds. In the two most recent races, he qualified fifth on the grid, results he believes were partly affected by the fuel system problem. Norris also said he recognized there were areas where he could improve.

Singapore’s Marina Bay circuit has few long straights and is among the least power-sensitive tracks on the Formula 1 calendar, so any gain from the fix may be less apparent than at recent venues. Norris said straights were not as important there as they had been in the previous few weekends, but that he still expected the car to travel down them at its proper speed. “It’s always tough when you come out of corners better and end up going slower,” he said.

Norris said McLaren had put substantial work into diagnosing the issue and that he was confident in the team’s effort. He added that he would have to drive the car before knowing whether performance had improved. With a close contest expected among the top four teams, McLaren is using the first practice session, FP1, to check whether the changes have addressed the problem.

Singapore is also a test of whether McLaren’s poor showing in Malaysia was an isolated result. Sepang was expected to suit the strengths of the MCL40, but McLaren was only the fourth-fastest team there. The car’s aerodynamic behaviour on the circuit’s extremely rough surface was identified as a possible factor.