Daniel Ricciardo says his lack of running during Friday practice for the Spanish Grand Prix was to be expected.
The Australian managed just nine laps in the morning before his Red Bull team had to change the Renault engine, which was at the end of its cycle as it had already been used.
Red Bull spent much of the afternoon session fitting the fourth engine Ricciardo will use this year, and he completed just four laps.
With the team trying to avoid using a fifth engine before Monaco - where the penalty for starting from the back would be bigger - Ricciardo knew today he would not get much done.
"We expected today to be limited with mileage," said Ricciardo. "Obviously we had to put in the fourth engine, which I guess was on the plan.
"As I said, we knew we wouldn't do much today. With the laps we did I think we have a lot to learn. It would have been nice to get more running.
"We had quite a few updates today, so I think trying to get them working in the correct window is something that we have to discover."
Ricciardo admitted it was frustrating to be in his situation after four races.
"We all know it's not quite acceptable," he said of his engine situation.
"It's out of my control. I'm doing what I can with what I've got."