Lotus's difficult 2014 season continued on Tuesday as they suffered a disrupted day of running during testing in Bahrain.
The E22 suffered two power unit related failures which restricted Pastor Maldonado to just 16 laps.
Lotus has failed to score a point so far in 2014, although both drivers finished last weekend's Bahrain Grand Prix.
"This morning our programme was focused on aerodynamic work and we achieved a lot, even with a limited amount of laps," said Maldonado.
"This afternoon the plan was to work on performance, evaluating parts and set-ups, however we have not been able to run though the programme due to power unit issues. We need to check and understand what has happened.
"This is what testing is for even though we would have preferred to have been able to complete more laps today."
Maldonado's Lotus team-mate, Romain Grosjean, will take over testing duties on Wednesday.