99 Suburban

If it cranks good but won't start, have a helper crank it while you check for spark at the plugs. If you have spark everywhere, use a gage and check fuel pressure. Some of the national brand autostores used to loan out a fuel pressure gage.

Battery has a full charge and all connections are good?

I wouldn't suspect the pump without testing fuel pressure, even then, I'd have to check for voltage and ground at the fuel pump connector. When you first turn on the key, no crank, can you hear the pump run for a few seconds?

How about spark at the plugs? You can pull spark plug wire loose from spark plug. Use known good spark plug or spark tester in the plug wire boot, Ground/touch metal part of tester to metal part of engine, engine cranking watch for spark.

I asked if you could hear the pump run for a few seconds, key on, no crank? Fuel filter ok? Don't take any fuel lines loose, unless your sure there is no pressure on the system.

At the fuel pump connector, gray wire is voltage, black is ground, engine cranking, if good voltage and ground with no pump action, suspect the pump.

Voltage and ground.

How about fuel pressure test?

Voltage and ground at the pump connector, engine cranking.

Besides using a fuel pressure gage, also use a noid lite and check for injector pulse. Engine cranking, if the injector has voltage and ground, the lite will pulse.

If we can rule out the fuel pressure issue, we can move on.