93 gmc sierra 5.7 liter engine, injection carb, will turn over won't start, replaced fuel pump fuse, replaced fuel pump relay, replaced fuel pump inside gas tank, no gas flow to carb , gas gauge has always read improper gas levels, so i tend to run on empty alot, one week prior to trouble "check engine" light came on, but truck was running normal, no sluggestness in engine, all fluid levels were normal, everything was fine...thanx in advance "

Sounds like your injectors are not metering fuel. If I remember correctly, your system is fired off of the ignition module. This would at least be a good place to start.

if your carb is a tbi (throttle body injector) then the carb is clogged

The first thing I would check is fuel pressure. This type of fuel injection requires a minimum fuel pressure in order to operate. If fuel pressure is as little as one psi below minimum the vehicle will not start. You can try squirting a couple of shots of carb spray into the air snorkel while somebody cranks the engine over. If the engine starts and then dies you now you fpdeffinetely have a fuel issue. If the engine still won't start check for spark. Let me know what you find. Let me know if you have any questions and I'll do my best to answer them. Thank you for using FixYa.com!

I’m happy to assist further over the phone at https://www.6ya.com/expert/jeremy_d728a59f986299fa

If you are at or near the 100,000 mile mark then your fuel pump may have failed. If you remove the fuel filler cap and listen carefully at the filler neck while someone turns the ignition key to "run" [don't actually crank the engine] you should be able to hear the fuel pump buzz for about a second and a half as the key is turned On. If you don't hear the pump buzz then odds are your pump is dead. Your pump may have actually failed making it appear as though you ran out of fuel. Not to uncommon. Hope this helps and good luck!

install a fuel pump guage and check pressure at key on and start, it should hardly vary, it the pressure is constant check the injector signal with a noid light, while you are at it check spark(no spark no injector signal) you won't find a relay fuse

This year does not have a carburator,it is fuel injected.The filter is on the inner frame rail on the left side.Make sure and relieve the fuel pressure before removing the filter or it will spray fuel all over.You can do this by removing the fuel pump fuse or relay and start the vehicle and let it run tilit dies.Then turn off the key and replace the filter.You will still get some fuel coming out but it won`t be pressurized.Hope this helps.Good luck.

even though parts are new they also come with defects so it sounds as if when you turn the key you hear it working and other times not at all hmmm connections are tight ? could be faulty fuel pump or relay .

HI,WHAT I WOULD IS GET SOMEONE TO LIE DOWN WHERE THE FUEL TANK IS AND WHEN YOU TURN THE KEY ON YOU SHOULD HERE THE FUEL PUMP KICK IN. IF YOU DON,T, GRAB A TEST LIGHT AND GO UNDER THE TRUCK AND FIND THE WIRES THAT GO TO YOUR TANK, THERE SHOULD BE 3 OR 4 OF THEM AND THERE SHOULD BE A PLACE WHERE THEY UNPLUG. FIND THE WIRE THAT GOES TO YOUR PUMP BY TURNING THE KEY ON AND OFF. YOU MAY ONLY HAVE A WIRE OFF OR BROKE OR THE PUMP MAY BE BAD. I HOPE THIS HELPS. JIMBO

Yes it has a rubber cover over it in the engine compartment.i would change the relay.good luck.

The inline fuel pump fuse on the passenger side firewall is good? Are you jumping it with 12 volts at the test lead or the fuse?