2G Voltage Issue at Fuel Pump Plug

[NAS_T_2G]

Hey all, new here. Thanks for the add!

I have tried researching and looking on here, with no luck and am hoping somebody may be able to help.

I have a 97 GSX and am only getting 6 volts at the plug to the fuel pump. I have checked the voltage at the relay, at the dash and am getting 11.9 volts at both together, they are staying consistent when tested. That is with the relay unplugged and plugged in. I have replaced the relay twice with the same outcome. When I test at the plug where it plugs into the fuel pump, I am getting 6 volts with the relay plugged in and unplugged as well. I have also tried to use a new fuse(engine) at the fuse box under the hood to see if there was something I may have been missing with no luck. I have a new battery for it and had it double checked to make sure it's good and its tested good.

I am hoping somebody may have this issue before and can help me understand why the voltage is so low at the pump. The wiring in the car is 100 percent stock with no modifications to it. I pulled the transmission to have it rebuilt because it was bad when I bought the car. after installing everything it for some reason is now not working, the fuel gage on the dash is also not working along with this issue.

Any help would be much appreciated. I am open to any help and input to figure this out so I can get the car running again. Thank you!

 

[steve]

I have a 97 GSX and am only getting 6 volts at the plug to the fuel pump.

I have checked the voltage at the relay, at the dash and am getting 11.9 volts at both together, they are staying consistent when tested. That is with the relay unplugged and plugged in. I have replaced the relay twice with the same outcome.

When I test at the plug where it plugs into the fuel pump, I am getting 6 volts with the relay plugged in and unplugged as well. I have also tried to use a new fuse (engine) at the fuse box under the hood to see if there was something I may have been missing with no luck.
I have a new battery for it and had it double checked to make sure it's good and its tested good.

By relay I assume you mean the Fuel Pump relay next to the MFI relay on the late model 2G DSM.

I don't understand who you have have any voltage at the Fuel Pump if you have disconnected the Fuel Pump relay. The pump gets it's power from that relay.
You can have a low voltage from a bad ground, high resistance in the circuit, or a large current draw pulling the voltage down.

First we need to be more clear as to what you're doing and where exactly you're measuring. If you don't know the pin numbers at least provide the wire colors and locations.

 

[NAS_T_2G]

Hey Steve, thanks for the reply. I do apologize I mean voltage at the plug end prior to being connected to the pump assembly.

I will have to get the colors on the plug at the fuel pump when I return home. I do apologize about not including that.

With the battery in and connected with pos/neg, and voltage/power applied, with the relay unplugged I was able to test there with good voltage, however at the plug prior to plugging it in to the fuel pump assembly I’m only getting 6 volts.

I hope this helps clear up the confusion until I return home to get the wire colors for you.

Thank you

Again with the relay plugged in it’s the same voltage reading of 6 volts.

I only took out the transmission and replaced everything as it came out. I have no clue why all of a sudden I’m getting a voltage loss with the pump and gage working prior to uninstalling and reinstalling the transmission.

 

[steve]

The connector at the fuel pump has 2 pins. The AWD fuel pump uses pin 2 (Black/Blue) for it's power and pin 1 (Black) of the ground. There is also a connector for the senders for the gauges and warning lights.

The connector at the Fuel Pump relay has 4 pins. Two Black/White wires on pins 3 and 4 are the power feed to the relay. Pin 1 (Black/Blue) runs to the fuel pump connector and pin 2 (White/Red) to the ECU pin 8 to control the pump.