Question About EVAP System Smoke Test (612-specific)

Hello Gents. I posted this topic in the Tech Q&A section but thought I would drop it here also since my question is 612-specific and there might be more interest over here in this forum.

I'm troubleshooting a fuel smell on my 06' 612. There is no direct evidence of fluid leak that I can see, but there is a strong smell of fuel near the left-side fuel pump. The right-side pump does not smell at all. I'm planning to use my smoke machine to help troubleshoot and hopefully find the leak. I plan on injecting the smoke into the fuel filler, using a cone-adapter. My machine has a regulator that limits smoke flow to 1.5 psi, so I should be good there. Is there anything specific I need to do to the EVAP system in order to get a good test? I don't want to vent the smoke to the atmosphere, which will degrade the test. I know that the 612 runs an active self-test on the EVAP system during certain conditions...do I need to command any valves closed with my Launch X431? Also, I have read suggestions that nitrogen should be used, and not "shop air". Is there any danger with using shop air? Just trying to get a good, thorough test result before doing the fuel tank removal. I appreciate the help. Thanks in advance...
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