It’s my plow truck. 52 psi fuel pressure with key on and 55 in crank position. Replaced crank sensor.

It fires with ether.

any ideas???

tks
john

Fuel Injector fuse? Being a plow truck has it sat for a while where rodents could have got at some wires? You should be able to see 12 volts at the injectors
Have you checked for any codes? Really the only 2 sensors that won't make it start are crank, and coolant temp. It should still fire with all other sensors being faulty.

Does OBDII show RPM when cranking?

pull the fuse box under the hood up and look under it. mice love those trucks and I have seen at least a dozen of them with mouse houses and chewed up wires under there.

😂. Ain’t got not gas in it. It did sit all year (first year with plow attached) so I didn’t have to trouble shoot that dammm thing. But yes sat. Cked fuse box first and relay/fuse and all good. No signs of chewed up wires at all but will confirm in the not so visible areas. What psi do the injectors need to see?

I’ll confirm the 12 volts to injectors tomorrow.

So with that said and fires with ether? I’m stumped a bit. Regardless first year I leave plow hooked up and that functions just fine and now the cocsuker just decides not to start. The way it goes. 😂 lol

I haven’t confirmed that yet but good point

Also, my 5.3 would do the same when the air box was not hooked up. The mass air sensor did not see air flow so would not fire.
Also bad crank or cam sensor did the same thing.

I'm quite certain a 5.3 should start without the mass air flow, or cam sensor hooked up. I forgot to plug my cam sensor back in once and it would still run fine, just back fire once in a while on startup. With the Mass air flow disconnected, i thought the ECU had default parameters it just went to.

Ive got a 6.0 in my van that is giving me trouble starting. Thought it was the fuel pump again. If I turn the key to "start" right away it wont start very well if it starts at all. If i turn the key to "on" and wait 3 to 5 seconds it starts normally. Mine has about 330,000 miles on it.