You said you jumped the wires for the pump? Was that at the pump relay?
If you have a voltmeter or test light, keep the jumper wire in place and check for voltage at the fuel tank connector. The pump wire will be gray. With relay out and jumpered there, you should have battery voltage at the fuel tank connector. The key doesn't even have to be on, cause the relay has voltage to it at all times. If you jumpered it right (terminals 87 and 30 on the relay), and no voltage at the tank connector, you have a broken fuel wire somewhere between the relay and the fuel tank.
If you do have voltage at the tank, but the pump still won't work, only two possibilities, a bad pump or the ground for the pump is lost. Check the pump ground first.
SOURCE: '88 chevy truck, no spray from injectors
Not sure on that model what controls the injector pulse, but most vehicles either use the signal from the crankshaft position sensor or a cam position sensor. You should use a LED testlight, (NOT A BULB TESTLIGHT!!) and backprobe the injector terminals (with the other lead of the testlight to ground) while cranking the engine over. If the light flashes on one of the terminals, then you are getting injector pulse, and the fault lies elsewhere. If not, then you will need to replace whatver sensor is used to provide engine position signal on that model. Also, check the wiring to that sensor. Some vehicles have problems with the crankshaft pulley harmonic balancer failing and damaging either the body of the crank position sensor or its wiring.
SOURCE: 1987 chevy s10 2.5l tbi will not start. changed
That eliminates the crankshaft and camshaft position sensors. Have you checked the fuel injector itself for an open winding or stuck valve plunger? There should not be a steady 12 volts to the injector--if good injector, it would be spraying fuel steadily into the throttle body. But at least the engine should try to run if poorly. Take the injector out, dry it off with air, and intermittently apply 12 volts to one terminal while grounding the other. You should hear a click from inside every time you touch 12 volts. If not, replace it. If it does, it may be plugged with debris. Try blowing through it in reverse with compressed air.
SOURCE: have replaced fuel pump, relay & fuel filter.
have you checked to see if you have a bad came or lifter. that would make it backfire. if it kind of spits fuel it maybe cam. if it throws fire than it could be timing like a bad chain.
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