89 1500 will turn but won't fire

sounds like a bad fuel pump. open the gas cap and listen when you turn the key to the on position, not all the way to engage the starter, you should hear a buzzing for 5 or so secands that is the fuel pump in your gas tank. if you dont hear that buzzing the intank fuel pump is probley not working.

Almost fires? Do you mean it does fire some, that you know the plugs are getting spark? If so, then you probably need to have your fuel pressure tested to see if pump is working properly. Can you hear the pump buzz on briefly when you turn key to on? It should come on for a couple of seconds to pressurize the lines. If you don't hear it, then your pump may be bad, or something not turning pump on. Good luck.

It sure could be. But, first...by "won't turn over" you do mean it cranks at normal speed but won't start?
A simple test of the fuel pump is to stand by tank and listen as someone turns key to on. When first turned to on, your pump will activate for 2 or 3 seconds, pressurizing the fuel system, and then shut off if the engine computer doesn't get a cranking signal. Do you hear it come on? If not, then something's not turning your pump on. If you can hear it buzz on briefly, then maybe it's your filter. Another test: Spray a little starting fluid into your intake manifold (remove the big hose going into intake manifold) while someone tries starting it.If it doesn't fire and try to stay running, then it's probably an ignition problem. But if it does fire off, then you know it's a fuel problem-likely your pump or filter. good luck.

It can either be the fuel pump or the ignition module. Have someone listen by the fuel tank or take the gas cap off and use a screwdriver to open the metal door under the cap, as you turn the ke foreward, not far enough to crank the engine over but so all the dash lights come on. You should hear the fuel pump turn on for a few seconds. Fuel pumps work then not work then work right before the go out for good.

Ignition modules start to work only while the engine is cold, then eventually the won't work at all.

Good Luck

do you mean the truck won`t start and run or do you mean it won`t turn over with the key.if it won`t turn over with the key the you may have a starter problem.if you mean won`t start then it could be the fuel pump not working.with someone cranking the motor you should hear the fuel pump running with the gas cap off and listening at the filler neck.or hear it running listening under the truck at the gas tank.if you don`t hear it then you can hit the tack sharply with your hand or a rubber hammer,it hear the pump start to run then the fuel pump needs replacing.if not check the fuses under the dash and under the hood.if they are good then it may be the pump relay in the relay box under the hood and it should be marked on the box or lid.

turn key on and listen for fuel pump in the tank, it should go on for a few seconds then turn off. if you cant hear it try to listen at the fill cap when someone else turns the key on. if you cant hear it , check the safety shutdown relay under hood, it shuts down fuel pump and ignition

your crankshaft position sensor or its connector is bad

You first have to determine if its fire or fuel. To do this listen when you turn on the ignition switch, You should hear a buzzing sound from the fuel tank to indicate your fuel pump is working. If no sound check pump fuse and relay. If you hear the sound spray quick start into the intake manifold and try to start. If it starts or try's to start its a problem with fuel pressure or fuel filter. If you get nothing it's likely fire.

fuel filter or fuel pump needs replaced

thurn the key to the on position with out starting it and you should hear the fuel pump engage if not thats your problem