I took one semester of Biblical Hebrew, I hated it. 
It was so difficult getting used to the root system and how the vowels would change. Greek was so much easier.
In Greek “Before Abraham was, I am” is πρὶν Ἀβραὰμ γενέσθαι ἐγὼ εἰμί (prin Abra’am genesthai egō eimi). The English translation here is misleading. γενέσθαι is not the past tense of εἰμί like it appears in English where “was” is the past tense of “am”. Instead γενέσθαι is a totally different verb altogether, it comes from γίγνομαι (gignomai) which in this context best means “to become” or “to be born”. It’s the aorist infinitive. Regardless though the tense is pretty clear here, the first verb is in the past tense, the second present. It’s not ambiguous like אֶהְיֶה. Though… Jesus would have originally spoken this in Aramaic which is also a semtic language like Hebrew, so maybe the tense would have been ambiguous as well in the original . Regardless though I think by the way they translated this saying they understood him to be making a radical statement about being outside of time.
It’s interesting that the Jews who translated the Septuagint (3rd century BCE) translated אֶהְיֶה אֲשֶׁר אֶהְיֶה as ἐγώ εἰμι ὁ ὤν (egō eimi ho ōn)- “I am (the) Being”. I think I personally prefer “I am Being”, we don’t have to translate the article ὁ because Greek puts the particle in front of almost every noun, in a lot of places where we wouldn’t use the article in English. Anyways, the present tense is used here. ὤν is the present participle of εἰμι- “Being”. Greek doesn’t allow for the ambiguity in tense that Hebrew does, so maybe that’s the best the translators could do, and they couldn’t convey the lack of a tense in the Hebrew. Still it could also be that they understood אֶהְיֶה אֲשֶׁר אֶהְיֶה to be present and not past or future. A later early translation- Aquila and Theodoton- actually translated it in the future: ἐσομαι ὁς ἐσομαι (esomai hos esomai), “I will be who I will be”. So there was a question about the proper tense to use to translate אֶהְיֶה, and different translators made different choices on which tense to use. Guess we’ll never know why the Septuagint translators used the present tense, unless they ever invent a time machine. Maybe we could incubate a dream about it and ask them. 
I am also interested in why they used a participle instead of using εἰμι again, such as in ἐγώ εἰμι τις εἰμι (egō eimi tis eimi)- which would literally be “I am who I am.” Seems they wanted to emphasize the ontology (Beingness) of God- God as Absolute Existence. Later in the verse they use ὁ ὤν again- “This is what you are to say to the Israelites: BEING has sent me to you.” It’s actually possible that this translation “I am Being” is closer to the original Hebrew. Maybe what the Septuagint translators had in front of them wasn’t אֶהְיֶה אֲשֶׁר אֶהְיֶה but something else (I don’t know Hebrew so I’m not even gonna guess what that might have been). The earliest manuscript of the Hebrew Scriptures we have is the Masoretic text which dates from the 7th century CE at the earliest (it could be as late at the 10th century), almost a millennium after the Septuagint was translated. They are the basis for our modern translations. The earliest extant Septuagint manuscripts are from the 4th century CE, 3 centuries earlier than the Masoretic text if the earlier date for the Masoretic text is the correct one. They include this translation ἐγώ εἰμι ὁ ὤν. The translation might be much older though. We have historical evidence that the Septuagint was a translation of the Hebrew Bible ordered by the king Ptolemy II in the 3rd century BCE. It’s probably only the Pentateuch, the first 5 books of the Hebrew Scriptures, were translated at this time, not all of what has come down to us as the Hebrew Scriptures. Exodus is in the Pentateuch though, so it’s very likely it was translated at this time. So yeah do with that what you want 
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I actually forgot before reading the article that you posted that tense in Biblical Hebrew is ambiguous (I think scholars are still debating whether it actually marked for tense or not). I like that… God is, was, and will be: a reality separate from our experience of time. 
Just like your translation: “I am he who is, was, and will be he who is was and will be.”
Sorry for geeking out about the translation there, this is what I was trained to do in seminary and the habit dies hard .That’s probably more than you ever wanted to know about these verses.
EDIT: Just remembered that the Dead Sea Scrolls contained fragments of the Pentateuch. Exodus 3:14 is contained on fragment 4Q1. The text follows the Masoretic closely here, though the first אֶהְיֶה is illegible. Couldn’t find a date for this scroll, but material found in the cave it was in is dated to around 197 BCE–46 CE. So that puts it much closer to the Septuagint than I was working with above. This kind of knocks me down a peg haha. Still I wonder about that Septuagint translation… it seems to depart in a major way from the Hebrew. 
Glad you found it helpful. If you have any other Bible verses you’re interested in, I’m happy to take a look. 
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