I have 96 suburban that won't start. We replaced the fuel pump 7 months ago. The fuel filter last week. Every few days it won't start, but now not at all. It tries to, but it won't engage, it acts like it's out of gas but I know there's at least 10 gallons in it. What do we try to replace next?
Spray some starting fluid into the engine with the throttle held open and see if it will start. If it starts it's a lack of fuel, if it doesn't it's something else.
If you don't have a fuel pressure tester, pull the schrader valve out of the test port on the fuel rail attach a hose to it and have someone crank the engine. If you're not getting fuel, pull the fuel pump relay and test for power key on engine off on terminals 30 and 85. ground on terminals 86 and 87.
If terminal 87 isn't grounded check the wiring from the relay to the pump. If that's OK, lower the fuel tank and check the ground wire to the pump. It should ground on the frame rail near the leaf spring.
If both wires check out, pull the pump and bench test it by applying power and ground to the respective terminals. IF it doesn't spin replace it.
If terminal 30 doesn't have power, check your fuses.
Terminals 85 and 86 are ignition voltage and computer controlled grounds.
Of course check spark as well. Pull a wire put an old spark plug in there and ground the ground body of the plug against the engine. If you don't have spark check power and ground to the ignition coil. If both those are OK you want to put a test light on whichever wire sends the firing signal to the coil.
Check for codes in the engine computer and if your truck has a security system make sure the anti theft light isn't flashing when you're cranking.