96 s10 2.2l ???

im having problems with fuel pump, im only getting 5 volts at the fuel pump. traced the wire all the way back to the ecm and cheked it there and still am only reading 5 volts. when i turn the key on i hear the relay in the glove box kicking on/off but the fuel pump does nothing. i checked the fuse on the side of the dash and thats good.
what could be causing me to only get 5 volts coming out of the ecm, does that mean i have a bad ecm. could this be an issue with the oil pressure sending unit that i see alot of people talking about.
thanks for any help anyone can give me
1996 s10 2.2l automatic

has anyone checked the voltage in the grey wire going to the fuel pump? did you get 5 or 12 volts. in the back of the haynes manual in the wiring schematic drawing section, it shows a section showing some wires with 5 volts but now going to fuel pump. appreciate any help anyone can give me