Ford's F-Series and its EcoBoost engine are selling well. Photo Credit: Ford

When it comes down to profits for Detroit automakers, full-size pickup trucks are the key to mountains of cash. Analysts estimate that full-size pickups bring in the majority of Ford's (NYSE:F) and General Motors’ profits, so anything that helps sell pickups is huge. Here's good news for Ford investors: Its fuel-efficient EcoBoost engine seems to be doing just that.

Ford’s F-150 EcoBoost sales have reached 400,000 in the U.S. since its launch in February 2011, the company announced this week, and it continues to help F-Series sales surge, which are up 20% year to date. If F-Series sales top 50,000 in any given month, Ford considers it a solid month -- and sales have topped 60,000 for the last six consecutive months.

“Ford is delivering great fuel economy across our lineup, from EcoBoost in our F-150 and 15 other vehicles to our electrified vehicles,” said Doug Scott, Ford truck group marketing manager, in a press release. “Fuel economy is the No. 1 unmet need for truck customers, which is why the F-150 EcoBoost’s leading combination of fuel economy and capability is resonating so well.”

The F-150 and EcoBoost is resonating well with consumers, indeed. According to Ford, the F-Series is outselling its nearest competitor in the western U.S. market by 67%, where Ford says "housing and technology industries are driving truck sales"; the EcoBoost has proved a popular option, and has a take rate of 45%. Ford says that in the U.S. northwest, "F-150 customers choose EcoBoost 45% of the time compared to the national average of 38%."

Ford recently marked production of its 2 millionth EcoBoost engine. It was launched in 2009. Factory output averages more than 100,000 engines per month, up from 65,000 units in 2012, according to Ford.