1987 Chevy pickup,5.0 engine,throttle body fuel injection…won’t start, if spray ether it will start and stop, when turn key on, can’t hear fuel pump come on…new fuel pump, new fuel filter, new fuel pump relay, new fuel switch for the 2 tanks…Please help any other ideas?
Verify that the pump is not running. As I recall, replacing the tank after changing the pump and getting the electrical connector hooked up is a tricky, arm twisting job on these…That is where I would start to look…If that checks out, hot-wire the pump through a dashboard switch…
Start with the relay, make sure the output side is hot with the key on, then go to the tank and see if you have a hot wire there. If not repair or replace wire from tank to relay. Check ground wire from tank with a continuity tester to frame. If everything tests ok pull fuel pump and take it back to where you bought it and see if they can get it to spin. If you don’t find any of those wrong I’m stumped.
Get mechanic’s stethoscope, place end on gas cap and have somebody turn the key to the run position.
You may also want to check if this vehicle has an inertia switch. That’s a switch that senses an accident and disables the fuel pump circuit to prevent fuel-fed fires.
One other possibility is if it has an oil pressure sensor that disables the fuel pump if the oil pressure is zero to prevent engine self-destruction. If that’s not functioning the fuel pump won’t turn on. My '72 Vega had one of these.
I don’t know if your vehicle has these systems. I’m just offering ideas to look into.
For some reason, GM fuel pumps are notorious. You have to use GM but I’ve got three bad ones in a row so don’t discount that you may have gotten a bad one out of the box. Also, you need to change the harness in the tank and also make sure the connectors have good contact with a good ground. On this one, can’t you pull the box off to get good access to the tank instead of dropping the tank?