2005 6.0, injectors do not buzz with key on, but starts... WTH..

[rocksalt]

in 2020, the truck stopped starting. I checked so many things. FICM had 48V on the FICM terminals, low pressure fuel side good, RPM for start good(700+), no start.. Then 3 years later I put some new batteries and after some long cranking it started. Still no injector buzz at key on.. but starts right up. How do I get the injector buzz at key on?

 

[DEEZUZ]

That's an old software flash. It's not needed.

 

[Dieseldreamer23]

in 2020, the truck stopped starting. I checked so many things. FICM had 48V on the FICM terminals, low pressure fuel side good, RPM for start good(700+), no start.. Then 3 years later I put some new batteries and after some long cranking it started. Still no injector buzz at key on.. but starts right up. How do I get the injector buzz at key on?

I think Deezuz is probably on the right track. Some versions of the FICM software (of which there were numerous revisions) did not have a key on injector buzz. Some did, some didn't, and some even had key off injector buzz. In the end, the final Ford version for all models years DOES have key on injector buzz. The feature was added to precycle/test the injectors and improve cold starting. If you're going to keep the truck, do yourself a favor and get a PHP FICM tune on there and ditch the OEM garbage software you have on there now. You'll be very glad you did. FICMrepair rents the tuners and does FICM tuning in house. --
I will say that I did once have a guy with all 8 injectors not buzzing. He DID have the latest Ford software so they should have been buzzing. In the end, the guy was found to have an entire set (all 8) of dead injecters. I know that sounds crazy, and it's odd as heck, but it's what happened. New sticks made the truck buzz again and run again.