Ojalá el proyector no fallara justo cuando me tocara empezar la presentación.

Ojalá is a very common way to express a strong wish, similar to I wish or hopefully.

In this sentence, Ojalá sounds especially natural because the speaker is expressing a hoped-for situation that is uncertain and outside their control.

Compare:

• Ojalá el proyector no fallara... = I wish / If only the projector wouldn’t fail...
• Espero que el proyector no falle... = I hope the projector doesn’t fail...

Both can work, but ojalá often sounds more emotional or more like a wish.

Because ojalá is followed by the subjunctive when it expresses a wish.

Here, the speaker is not describing a fact. They are talking about something uncertain: whether the projector will fail or not. That uncertainty triggers the subjunctive.

So:

• Ojalá ... no fallara = wishing that it would not fail

This is a standard pattern in Spanish:

• Ojalá llueva. = Hopefully it rains.
• Ojalá viniera. = I wish he/she would come.

Both are possible, but they create a slightly different feel.

• Ojalá el proyector no falle...
  This sounds like a present/future wish: I hope the projector doesn’t fail / won’t fail.

• Ojalá el proyector no fallara...
  This sounds more like I wish the projector wouldn’t fail, often a bit more hypothetical, cautious, or emotionally distant.

In your sentence, the imperfect subjunctive gives the whole statement a more hypothetical tone, especially because the next verb is also in the imperfect subjunctive: tocara.

Cuando can take either the indicative or the subjunctive, depending on meaning.

Use the subjunctive after cuando when you are referring to a future or not-yet-realised event.

Here, justo cuando me tocara empezar la presentación refers to the moment when it would be the speaker’s turn to begin — a future or hypothetical moment from the speaker’s point of view.

So:

• cuando me toca = when it is my turn / when it usually happens
• cuando me tocó = when it was my turn
• cuando me toque = when it is my turn (in the future)
• cuando me tocara = when it would be my turn / when it were my turn

In this sentence, tocara matches the hypothetical wish introduced by ojalá.

Here, tocar means to be someone’s turn.

So:

• me tocara empezar = it would be my turn to start
• more naturally in English: right when I was supposed to start or right when it was my turn to start

This is a very common use of tocar in Spanish:

• Me toca hablar ahora. = It’s my turn to speak now.
• Nos toca pagar. = It’s our turn to pay.
• Le tocó conducir. = He/She had to drive / It was his/her turn to drive.

Because the speaker is wishing for the projector not to fail.

• fallar = to fail / to malfunction
• no fallara = would not fail / wouldn’t malfunction

This is simple negation:

• Ojalá llueva. = Hopefully it rains.
• Ojalá no llueva. = Hopefully it doesn’t rain.

Yes, but in this context fallar means to malfunction, to stop working properly, or to let someone down.

With machines and devices, it is very common in Spanish:

• El ordenador falla. = The computer is acting up / malfunctioning.
• El micrófono falló. = The microphone failed / stopped working.
• El proyector no fallara = the projector wouldn’t fail / wouldn’t stop working

So this is very natural Spanish for equipment problems.

In Spanish, articles are used more often than in English. So where English might say the projector or even just projector in some contexts, Spanish usually wants the article.

Here el proyector is the natural way to refer to the specific projector involved.

Similarly:

• La presentación
• El micrófono
• La pantalla

Using the article here sounds normal and expected in Spanish.

For the same reason: Spanish generally prefers the article when referring to a specific thing already understood from context.

• empezar la presentación = start the presentation

If you said just empezar presentación, it would sound incomplete or unnatural in standard Spanish.

Justo cuando means just when or right when. It adds emphasis and often suggests bad timing.

So:

• cuando me tocara empezar = when it would be my turn to start
• justo cuando me tocara empezar = right when it would be my turn to start

It gives the sentence a stronger sense of of all moments, that one.

Grammatically, it uses the imperfect subjunctive, but that does not automatically mean past time.

In this sentence, the idea is mainly hypothetical: the speaker is imagining or wishing about a possible situation.

A natural English translation might be:

• I wished the projector wouldn’t fail right when I had to start the presentation.
• or I wish the projector wouldn’t fail right when I’m supposed to start the presentation.

The exact time depends on context, but the Spanish is focused more on wish/hypothesis than on a simple time reference.

Yes. In Spain, both forms are correct:

• fallara / tocara
• fallase / tocase

So you could also say:

Ojalá el proyector no fallase justo cuando me tocase empezar la presentación.

Both are grammatical. The -ra forms are generally more common in everyday speech.

A Spaniard could definitely say this, and it is perfectly natural. However, in everyday conversation, many speakers might choose a slightly simpler version depending on context, such as:

• Ojalá el proyector no falle justo cuando me toque empezar la presentación.
• A ver si el proyector no falla justo cuando me toca empezar.

Your original sentence sounds natural, but a little more reflective or stylistically careful because of the two imperfect subjunctives: fallara and tocara.

They match because the whole sentence is framed as a wish about a hypothetical situation.

• Main wish: Ojalá ... no fallara
• Time clause linked to that wish: cuando me tocara empezar

Using the imperfect subjunctive in both places creates a consistent tone: the projector failing and the moment of starting are both presented as part of the same imagined scenario.

If you changed one tense, the sentence would feel less balanced or could shift meaning.

For example:

• Ojalá el proyector no falle justo cuando me toque empezar...
  More straightforward future wish.
• Ojalá el proyector no fallara justo cuando me tocara empezar...
  More hypothetical or emotionally distanced wish.