Fuel Is 11.08 VDC too low supply voltage for running fuel pump?

[vferrizz]

After tons of other troubleshooting, I am back to fuel supply questions. I have been dealing with a KOEO code 96 for a while now. With the key on and the inertia switch disconnected, I decided to measure the supply voltage to the green/yellow wire on the intertia switch and got full battery voltage (12.68 VDC). I did the same thing on the brown/pink wire out of the switch and also got 12.68 VDC. To me, that tells me I am getting good voltage from the battery, thru the fuel pump relay and through the intertia switch, unless my logic is hosed. I then jumpered the test connection so I could run the fuel pump continuously with the key on. With the pump running, I got 11.09 VDC on the inertia switch green/yellow wire and 11.08 VDC on the inertial switch brown/pink wire. Is this too low of a running voltage for the pump? If so, it would explain the code 96 and may be an indication that my fuel pump is tired and needs to be replaced? If it were a tired fuel pump, it would also explain why my car starts and idles fine but sputters under load.

 

[AeroCoupe]

Could also be a plugged fuel filter or strainer on the pump causing it to work harder than it should and not provide enough fuel. If you do not know the condition of those two items it’s hard to say it’s the pump. There is also a connector just above the fuel tank at the back of the car that connects the fuel pump and sending unit. There have been instances of a poor connection at this connector.

 

[vferrizz]

Thanks AeroCoupe for the suggestion. Time to bust out the jack and jack stands and see what is under there.

 

[90sickfox]

I second that fuel filter check. There was a good write up here on that code 96. It ended up being a bad connection at a wire behind the drivers kick panel. Worth checking. If I remember correctly the connection in the connector heated up and left a burn mark. I've helped a couple people with this pic. Wish I knew where to find that thread.

 

[Blown88GT]

After tons of other troubleshooting, I am back to fuel supply questions. I have been dealing with a KOEO code 96 for a while now. With the key on and the inertia switch disconnected, I decided to measure the supply voltage to the green/yellow wire on the intertia switch and got full battery voltage (12.68 VDC). I did the same thing on the brown/pink wire out of the switch and also got 12.68 VDC. To me, that tells me I am getting good voltage from the battery, thru the fuel pump relay and through the intertia switch, unless my logic is hosed. I then jumpered the test connection so I could run the fuel pump continuously with the key on. With the pump running, I got 11.09 VDC on the inertia switch green/yellow wire and 11.08 VDC on the inertial switch brown/pink wire. Is this too low of a running voltage for the pump? If so, it would explain the code 96 and may be an indication that my fuel pump is tired and needs to be replaced? If it were a tired fuel pump, it would also explain why my car starts and idles fine but sputters under load.

It's most likely the fuel pump. Engine off, pump running will drop the voltage to the pump.

 

[vferrizz]

Makes sense, thanks. Pump is wicked noisy and original so I figured may as well replace it. Pretty sure the original is tired.

 

[vferrizz]

I second that fuel filter check. There was a good write up here on that code 96. It ended up being a bad connection at a wire behind the drivers kick panel. Worth checking. If I remember correctly the connection in the connector heated up and left a burn mark. I've helped a couple people with this pic. Wish I knew where to find that thread.

Thanks I will take a peek at this. Still have my ECU out for troubleshooting purposes. I'll dig for that post as well.