ncgoblin's Build Thread - 2005 SS/SC North Carolina

[ncgoblin]

Your wires are not lining up with the diagram I provided... from my 2006 Cobalt SS and maybe your 2005 has a different fuel pump. I think my diagram is wrong for your car.

View attachment 11309

I have the older 05 SS fuel pump which has a different larger plug. What is your take on re-routing the low reference wire to the BCM plug pin 66 show above?

 

[Ross]

The low reference should be the same. I would pull out an electrical meter, and measure voltages at Empty, Full, current low reference, and at the other low reference before I started re-wiring. I wonder how it got mixed up from stock wiring.

 

[Karter2026]

Here is the 05 2.0 diagram.

 

[Ross]

Here is the 05 2.0 diagram.

Ron, is there a diagrams for the fuel sender and gauge?
The first diagram only shows low reference going to the fuel sender, the second diagram shows the fuel pump.

 

[Karter2026]

Ron, is there a diagrams for the fuel sender and gauge?
The first diagram only shows low reference going to the fuel sender, the second diagram shows the fuel pump.

The powertrain management is the best one i could find its color too!

 

[ncgoblin]

The low reference should be the same. I would pull out an electrical meter, and measure voltages at Empty, Full, current low reference, and at the other low reference before I started re-wiring. I wonder how it got mixed up from stock wiring.

So...I was impatient and last evening swapped the wires before you gave me some great advice and...now when I plug in the float in it only reads full and does not adjust to motion. I pulled the float apart and seems very simplistic with a contact but I assume its defective. I did measure the fuel level sensor signal (ye/wh) at .014 and .005v at the Low Reference (pnk/red).

 

[ncgoblin]

The powertrain management is the best one i could find its color too!

This is awesome

 

[Ross]

It looks like the fuel sender is a variable resistor that goes from the Low Reference to the PCM. It shouldn't matter if you hook the variable resistor up backwards. I should pull my sender and measure it...

 

[ncgoblin]

It looks like the fuel sender is a variable resistor that goes from the Low Reference to the PCM. It shouldn't matter if you hook the variable resistor up backwards. I should pull my sender and measure it...

I do not believe this is fused based on the diagrams you posted either so its odd that it now just sits at full if I unplug it it goes to empty but does not adjust now that I swapped wires. I installed them back to normal and still sits at full.

 

[Ross]

Check for a stray wire causing a short on the sender, as it sounds like it is shorted.
Check the sender while hooked up to an electrical meter, and see if it will vary the resistance.
Put a variable resistor in place of the sender, and see if the gauge goes up and down. If so, it is a bad sender.

 

[ncgoblin]

Check for a stray wire causing a short on the sender, as it sounds like it is shorted.
Check the sender while hooked up to an electrical meter, and see if it will vary the resistance.
Put a variable resistor in place of the sender, and see if the gauge goes up and down. If so, it is a bad sender.

Thanks Ross I found the short it was on circuit 2759 to pin 29 on C1 plug. Now the sender adjusts when I lift the arm it goes to empty and when all the way down its full so its backwards correct? This is the wiring layout through the entire circuit to C1 PCM plug.

Below is how the sender unit is wired currently.

Sender Unit	Fuel Pump Plug	C1 to Fuel Pump Plug	C1 Pin / Circuit	Circuit Name
Grey Wire	Yellow/White	Purple	12 / 1589	Primary Fuel Level Senor Signal
Green Wire	Pink / Orange	Tan	29 / 2759	Fuel Tank Pressure Sensor Low Reference

 

[Vwsaabvt]

Thanks Ross I found the short it was on circuit 2759 to pin 29 on C1 plug. Now the sender adjusts when I lift the arm it goes to empty and when all the way down its full so its backwards correct? This is the wiring layout through the entire circuit to C1 PCM plug.

Below is how the sender unit is wired currently.

Sender Unit	Fuel Pump Plug	C1 to Fuel Pump Plug	C1 Pin / Circuit	Circuit Name
Grey Wire	Yellow/White	Purple	12 / 1589	Primary Fuel Level Senor Signal
Green Wire	Pink / Orange	Tan	29 / 2759	Fuel Tank Pressure Sensor Low Reference

Down is empty up is full, reverse the wires

 

[ncgoblin]

Down is empty up is full, reverse the wires

Correct it’s backwards trying to wrap my head around the problem when the circuits seem to align.

 

[ncgoblin]

Down is empty up is full, reverse the wires

Reversing the wires does not resolve the issue.

 

[Karter2026]

That pink and orange wire spliced in to a tan wire for fuel tank pressure sensor then splits to the pcm with that same tan wire. Is there a chance that wire is cut at that splice.

I haven't been following this real close other than posting those diagrams.

 

[ncgoblin]

That pink and orange wire spliced in to a tan wire for fuel tank pressure sensor then splits to the pcm with that same tan wire. Is there a chance that wire is cut at that splice.

I haven't been following this real close other than posting those diagrams.

I checked continuity from the pcm all the way back to green wire on the sender and get .3

 

[Ross]

So I pinned the back of my 2006 Cobalt's fuel connector, then plugged it in to the fuel pump so I can measure voltages.
The black and grey are both 0 volts = ground.
The purple was 0.711 volts when the tank is full,
0.810 volts when I "removed fuel" by tilting the car with the jack.
5.050 volts when not plugged into the fuel pump (reads empty on the fuel gauge)
The pinkish wire is .004 volts.

 

[ncgoblin]

So I pinned the back of my 2006 Cobalt's fuel connector, then plugged it in to the fuel pump so I can measure voltages.
The black and grey are both 0 volts = ground.
The purple was 0.711 volts when the tank is full,
0.810 volts when I "removed fuel" by tilting the car with the jack.
5.050 volts when not plugged into the fuel pump (reads empty on the fuel gauge)
The pinkish wire is .004 volts.
View attachment 11324View attachment 11325

My purple is .7 empty and 1.5 full so opposite

 

[Lonny]

Have you bent your float wire in a different direction?

 

[ncgoblin]

Have you bent your float wire in a different direction?

Here is the float. I will say this issue came up after I got my car tuned. The PCM was flashed with another customers Goblin code I wouldn’t think this would be programmed in the PCM but maybe?