no voltage to fuel pump

[kbeefy]

'02 astro with all the bells and whistles. Was Idleing a while back and died. Wouldn't start. Having had an astro before, I checked for fuel pressure on the rail. Nothing. Swapped Fuel and AC relays, Nothing. Put a jumper directly to the output terminal of the fuel pump relay, nothing. OK, I must need a fuel pump.

Tonight, I finally sneak this thing onto a lift. Drop the tank, look at all the plugs, they look fine. Put power to the pump, it runs. Dang it. Check for power at the big plug going to the pump, nothing. Tried with the key on, Tried jumpering the relay. Still nothing. My schematic doesn't show anything between the pump and the relay, fuel quantitiy still works, what am I missing?

[old_master]

The gray wire at the pump comes from the relay. It should show battery voltage for 2 to 3 seconds when the ignition is turned to the RUN position. It should show battery voltage constantly when the ignition is in the START position. There are two black wires in the fuel pump module electrical connector, both of them should be less than 5 ohms to ground.

[kbeefy]

Originally Posted by old_master

The gray wire at the pump comes from the relay. It should show battery voltage for 2 to 3 seconds when the ignition is turned to the RUN position. It should show battery voltage constantly when the ignition is in the START position. There are two black wires in the fuel pump module electrical connector, both of them should be less than 5 ohms to ground.

Theres no voltage on the grey wire, ever. Not for the first 2 seconds, not when I jumper 12v to the relay output in the power distribution block under the hood.
I didn't try 12v to the red prime wire, my schematic shows it going to the normally closed position of the Fuel Pump relay, theres no connection in that terminal in the relay box. I also failed to check the ECM 'B' fuse, it looks to power that circuit. I'm gonna try to get over to it tonight and check for power in a few more places.

[kbeefy]

Stupid ECM-B Fuse. It was blown. Replaced it and pump ran for a bit and blew the fuse. I shoulda installed that pump anyways, now I need to drop the tank again.

So, my harness forward of the tank didn't look melted or corroded, as a matter of fact all the plugs looked to be in near new condition. Aside from the aforementioned 5 ohm resistance check and burnt plugs is there anything else I should look for, wiring wise?

[old_master]

Disconnect the pump, connect a 15 amp fused jumper wire from battery positive to the fuel pump prime wire under the hood. If the fuse pops, locate and repair the short circuit. If it doesn't pop, replace the fuel pump.

You can also check resistance to ground on the gray wire at the pump connector. With the ECMB fused removed, and the pump disconnected, resistance to ground should show an open circuit, (infinite resistance).