Hi guys I have an issue with only getting 8.5 volts to my fuel pump via the connector in the back next to the gas tank. I then tested the voltage going to the relay and had the full 12v so someone had mentioned to check the wiring from the bulkhead(C100) to the connector in the back. Thoughts ? Also which pin is it for the fuel pump in the bulkhead ? I have an 86 iroc with a 305

 

It's a tan/wht wire from engine bay, terminal G4. Not sure if it's still tan/wht on the interior side or just tan. Either way it runs down the driver side sill panel.

At the relay in the engine bay,

The two thin wires,
DK GRN / WHT: Relay Control
BLK / WHT: Chassis Ground for relay control

The two thick wires,
ORG: Fused power from Battery B+
TAN / WHT: Fuel pump

 

Hey thanks for the help, I got under the car yesterday day and ran 12v straight to the connector coming off the pump and I have 0 response, so looks like I have to drop the rear end and replace it 😅

Unless I powered it up wrong ? Do I need to ground the relay wire as well the ground ? And then run the 12v ?

 

You don't need to remove the rearend from the car, but you will need to disconnect the shocks and drop it down as far as possible without damaging the brake hose.
You will also need to drop the rear part of the exhaust and heat shield to get the fuel tank out...

 

Sorry I didn't clarify, I know what you mean I've been studying for a little while, with videos and the forums in here seems like a pretty big job !

 

Correct, pump is normally hard wired to ground (chassis) and the on/off function is done by switching of the high side (+12V). Although I don't know if your ground is still any good, that's something you should maybe determine before bothering to replace pump.