My guess? Fuel pump wiring. Check the connectors for the fuel pump back at the tank. I'd wager your old pump was fine as well. Check fuses? There are 2 fuses for the fuel pump. One under the hood, and one under the dash.

Isolate the fuel pump as a problem first. Pull out the fuel pump relay and jumper the two connectors so that the pump runs while the key is on. This bypasses the fuel pump circuit through the "start" position and the charge relay / alternator issues.

Truck off, key on, make sure you can hear the pump running when you put the jumper in. Wiggle the connector back there. It should not cut in and out.

If pump is running with the jumper and appears solid, try starting.

Jumper:




BTW, it appears the fuel pump relay has moved around depending on year and engine. The jumper is the same. Just make sure your jumpering the correct relay.

If the truck starts up and runs, try isolating the alternator. Put the fuel pump relay back in and pull and jumper the Charge relay. If truck still starts and runs, you've got a wiring issue in the alternator circuit.


--Dan

I would rule out the O2 sensor as a problem as being a '90 it is probably a single wire and will only put the vehicle in "limp-in" mode but will not create the type of problem you are describing.

I highly agree with Dan regarding the fuel pump wiring....been there/done that too many times to even tell you. And I've heard very similar stories from many here on the wire about the same type of situation. Those harnesses are very prone to rotting and sometimes what appears to be a sound connection can actually be hanging on by a thread. Living here in the North Country with more road salt in the winter months than actual paved road.......my connections are now a product of my own "yankee ingenuity".....I've had them rot at every possible connection from the top of the tank out.....even tried a "trailer hitch harness" as an alternative then got smart and came up with my own solution.

HTH...

dawn...

Good pictures, thanks.

I used the jumper and I can now hear the fuel pump. Unhooking the line at the rail results in the spewing of fuel. It still won't start though even if I hit it with starting fluid. My buddy didn't come through with the fuel gauge, so I haven't been able to actually check the pressure.

It still won't start though even if I hit it with starting fluid.

Then you do not have a fuel issue. You have an ignition or compression issue. The later can probably be ruled out. You need to look at the distributor, ECU, wires, coil. Coil is probably your best bet and the wiring associated with it, as you are not getting spark to any of the cylinders. A bad wire or bad cap would most likely cause one or two holes to drop, not all of them.

Good Luck,
Michael

BETER QUITE USING STARTING FLUID IN THAT ENG OR THE TOPS OF THE PISTONS WILL BE HITTING THE BOTTOM OF THE OIL PAN, DO LIKE MIKE SAID START ON THE BASICS , IF YOU HAVE AND IT WON,T START , TAKE A LOOK AT THE DIST, PULL THE CAP AND MAKE SURE IT IS SPINNIG WHEN THE ENG IS CRANKING OVER ,IF NOT GO AHEAD AND PULL THE HEAD YOU HAVE BROKEN BELT OR AT THE WORSE A BROKEN CAM, BUT FIRST TURN THE KEY TO THE RUN POSITION AND SEE IF THE CHECK ENG LIGHT IS ON , IF IT IS NOT ON THE ENG WILL NOT START , IF NOT ON CHECK THE MAIN RELAY MAYBE BE LABLED ENG RELAY , THIS IS THE MAIN PWR TO THE ECM, IF IT IS ON, NOW MOVE TO THE COIL AND THEN TO THE DIST AND ON TO THE IGN MODULE UNDER THE MANIFOLD , JUST REMEMBER THESE PARTICULAR PARTS ARE PRETTY DARN DURABLE AND THEY DON,T FAIL VERY OFTEN BUT ANY ONE OF THEM AND YOU ARE STUCK.JERRY