so I was talking to a buddy, told me if I run out of diesel in my 4230 it will do massive amounts of damage, is this true? am no terrified of running out of diesel. also how hard is it to replace fuel guage and fuel guage sending unit?
Although I don't recommend running inj pump out of fuel doing so will not normally damage anything unless maybe inj pump is ready to fail. I've accidentally ran my 4240 I once owned & my 4255 out of fuel just put fuel in tank,bleed the air out then started engine. Changing fuel gauge requires disassembly of dash & changing fuel sender requires one to be sure fuel level is below tank opening for fuel sender. Have you grounded sender wire with ign switch in on position to see if gauge moved? I'd suggest to check wiring bulkhead on firewall behind engine for corrosion before R&R of any components.
As we all know, running out of fuel isn't a good thing but IT WILL HAPPEN. It doesn't not cause catastrophic damage.
Most, if any damage occurs when the crud at the bottom of your tank gets pumped thru to the injection pump, hence a big reason to keep your filters clean/changed & in top condition.