Why won't my Gmc Yukon not start after running out of gas?

Answer 1

Fuel injected cars have an electric fuel pump that's powered by a switch that's activated by engine oil pressure. I'll explain later... Consequently, they won't pump fuel if the engine's not running.

Make sure the ignition switch is off. Under the hood, find the fuel log (tube or casting) that lays across the tops of the injectors. One end should have a fitting that looks very much like a tire valve. Remove the cap, place a small screwdriver or other suitable object against the valve core, cover the whole mess with a rag, and depress the core. Usually, they spit fuel in your eyes. Turn the ignition key to the "run" position, and you should here the fuel pump run for about 1 second. Turn the key off. If you have either a V-6 or a V-8, you should do the same for both banks of injectors. Run the whole "valve depress/ignition toggle" drill until you get more fuel than air coming out of the valve. At this point, try starting the engine. If it does start, it'll probably die and/or stumble until all the air is purged. If it does die, try purging some more air from the valves.

The reason for the pressure-activated fuel pump is safety: unlike the older, engine driven pumps that would run only with the engine running, the electric fuel pump would continue to run as long as there's power to it. Picture the outcome of a wreck where a fuel line is ruptured, the engine dies, but the fuel pump just keeps pumping.