No start condition unless I ground the yellow and red wire coming into the Injection Pressure Regulator?

It sounds like the Injection Pressure Regulator went bad, but can I ask if you have run the codes? This guide can help, also how did you come to find this problem of grounding the wire to make it start?

https://www.2carpros.com/articles/checking-a-service-engine-soon-or-check-engine-light-on-or-flashing

If no codes are present here is how to change the valve out for a new one in the images below. You can find a new unit on Amazon for $49.00.

https://amzn.to/3IcYZzP

Please let me know how it goes.

Let's run the codes to see what codes up.

Here is a guide to help you:

https://www.2carpros.com/articles/checking-a-service-engine-soon-or-check-engine-light-on-or-flashing

Please go over this guide and report back.