8.5v to the fuel pump???

[1.8laser90]

After i had my burnt up ecu rebuilt and put back in my fuel pump doesn't want to come on. It worked before i had the ecu rebuilt which is weird but i know the ecu isn't causing it to come on... But i did check the voltage back at the pump and when cranking the engine over it gave me 8.5-9 volts. i was told that the pump should have at least 12v. Any idea what would cause this, i tried using the jumper to pass the relay but it still didn't come on but, i saw 2 jumpers behind the battery so i might of used the wrong one... any tips or ideas would be great..

 

[funniegus]

You should rewire the fuel pump using at least 10awg wire. Did you check youre connections making sure theyre not corroded or dirty or loose?

 

[TotalEclipse112]

The pump should defenatly have at least 12 volts when cranking and running. The the other post said check your wiring and possibly rewire the pump. Other than that the only other thing that could effect fuel pump voltage is possible a bad connection in the fuel pump relay in the center consol below the radio.

 

[1.8laser90]

well i took a 12v car battery and hooked it up to the pump from the connector and nothing.. I'm guessing the pump is bad ? should i turn the key when send voltage to it, is the pump ground to the frame ?

 

[funniegus]

If you had it hard wired it should of turned on.

 

[TotalEclipse112]

Yes the pump is grounded to the frame but to activate it without energizing the relay it must be hard wired. 12 volts from the battery positive terminal and the ground has to go the the battery negative. Just supplying 12 volts from another battery wont work it has to have the same ground plane as the test battery or its an incomplete circut.