My shop did not ever experience a ECM or CEM making a car not run. (after about 1998, plenty before then)

I understand your frustration - but I think you are barking up the wrong tree. Replacing modules can get very expensive using the just guessing diagnostic method. However places such as xemodex can test modules (for most functions) and advise whether they think there is anything wrong. There was a time or two when my techs would insist a module was needed - and I shipped it to xemodex, then we found the real problem when the module came back (after xemodex declared it ok)

There have been times (have read on forums, and not personally found this) that foreign material in a gas tank has damaged new fuel pumps or prevented the pumps from working.

 

Welp, I took out the Delphi fuel pump, and replaced it with a used Volvo OEM fuel pump. The car crunk right up, and ran for 25 mins before it shut off . I'm not sure what's going on. I do find it weird that the ECM relay fuse gets hot.

 

Shorted Circuit in the CEM to the fuel pump relay.

 

I had a similar issue and ended up finding corrosion on the CEM connector pins, especially where the blue wire connects.Cleaning those and applying some contact cleaner made a big difference. I know it’s weird, but I once had wiring issues on a work rig and found a broken ground near the fuel system—looked it up while ordering Komatsu parts, and sure enough, same root problem. Worth checking grounds too.