Hi:
The regulator is actuated via engine vacuum. If you look at the attached pic, engine vacuum is supplied via letter A. What to do is first, remove the vacuum hose and check to see if there is any evidence of fuel in it. If there isn't, inspect the vacuum hose to make sure it is in good condition and not cracked, or disconnected.
Since the engine won't run, you have to connect a fuel pressure gauge to the system the same as if you are checking pressure. Then, using a vacuum pump, apply vacuum to the regulator. If it is working, pressure will drop. If there is no change, the regulator isn't working.
Since you told me that pressure is low, I assume you already know how to check pressure. However, and just in case, here is a link that explains how it is done:
https://www.2carpros.com/articles/how-to-check-fuel-system-pressure-and-regulator
Let me know what you find.
Joe
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Monday, November 11th, 2019 AT 6:53 PM