No, I don’t. Read Nava’s post. Read the IPA pronunciation of the Spanish pronunciation of jalapeno. American English speakers tend to pronounce the Spanish “e” as a diphthong. It is not a diphthong in Spanish. However, it’s not exactly the same as a short “eh” in English, either. If you know French, it’s the same vowel as the “é” in “clé.” Thinking about it some more, I suppose some will hear “AY” as a closer approximation. I hear “EH” is a closer approximation, and I’ve been corrected by Spanish speakers before on this, for example, not to pronounce “José” as “ho-ZAY,” but as “ho-SEH.” If you cut the American pronunciation of “AY” in half (that is, remove the second vowel in the diphthong), you’ve pretty much got the Spanish sound for “e.”
Not that I like about.com as a source, but read the explanation here.
Also, as I mentioned above, amongst Spanish speakers themselves the /e/ varies in openness, so it can range as allophones from something between [Ɛ] and [ei], depending on phonology (and regionalism, it seems to me).