exhaust fumes during engine start - A320

[IFLY_INDIGO]

During engine starts, packs automatically turn off. Only cabin fan is working for recirculation.

I have experienced exhaust fumes many times during engine start.

I wish to know how exhaust fumes enter the cabin/cockpit and Is there any trick to avoid it?

[Goldenrivett]

I wish to know how exhaust fumes enter the cabin/cockpit
This was discussed at great length recently.
http://www.pprune.org/tech-log/563271-a320-exhaust-smell-cabin-area.html

Keep up Pike!

[safelife]

Avionics venting.