Quadruple champion Sebastian Vettel's team completed just 14 laps in the first three days in Jerez after recurring problems. Other Renault-powered teams have also struggled to do much mileage.
The 26-year-old German left southern Spain on Wednesday with just 11 laps under his belt, having spent much of his time watching engineers working on the car.
"I am disappointed. I hate saying 'I told you so', but I'm disappointed because I did say I told you so and this is what's happened," Ecclestone told Reuters of a situation dubbed farcical by some.
Ecclestone has long been an opponent of the new and highly complex 1.6 litre power units, with energy recovery systems, which have replaced the old V8s.
The new units are more expensive, and in a bid to be greener and more road car relevant the emphasis is on fuel economy with drivers limited to 100kg of fuel compared to around 150kg previously. They also sound very different.
Ecclestone said Vettel, with whom he has a warm relationship, was no fan of the new era either.
"I know Sebastian is disappointed too because he's a racer. He likes to race," said the 83-year-old, who felt the new engine was better suited to endurance or the world touring car championship.
"I am upset because last year's championship, apart from the obvious that Sebastian ran away with things, was still a very good championship. This year I'm quite sure if we'd have left things as they were would have been an even better one."
Vettel won 13 grands prix last season, including a record nine in a row at the end as he wrapped up the title with three races to spare, but the most dominant team of recent years faces a real challenge now.
"We had an engine that was perfect, everybody liked the sound, it was reliable, didn't cause anybody trouble and was much, much more cheap than what they currently have to use," said Ecclestone.
"People loved the excitement of the noise we'd got before. And now I think that's all disappeared so I'm disappointed."
Red Bull principal Christian Horner said before the start of testing that the new power units could be so unreliable that half the field may fail to finish in the Australian season-opener in March.
Ecclestone said he would wait and see, with the Mercedes and Ferrari-powered teams putting in a more consistent amount of mileage.
"I'm hoping it's going to be like a wet race so we're not going to know who's going to win. That's the only thing that's good," he said of Melbourne.
"I think the cars will be unreliable. So you won't be able to go to a race and say 'My God, this guy's going to win easily', because you don't know. And even if somebody is leading a race you can't guarantee they are going to continue."
The quick-wearing Pirelli tyres drew considerable flak last year with the Italian company ultimately forced to make changes after a spate of blowouts and it could be the engine manufacturers' turn in the spotlight in 2014.
"We try to be positive," said Ecclestone. "In some ways, anything that's a little bit not too predictable is good."
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