Hey there!

Bought a L4 fuel system from Fore and the install was going okay. Bypass plug, new o rings, the works.

Then I got to the OEM fuel pump plug and now I’m fighting some issues. I cut and spliced the power wire to the FC3 controller, but where does the OEM plug ground go? (That would originally go to the plug on top of fuel pump). Fore said to tape it off and don’t ground it, which I did. Then I spliced the level sensor wires to the new sending unit, attempting to verify they worked with the new fuel hat within the tank. With no fuel in it and the level sensor at the bottom, it reads “OL”, but if I tip the tank to where the float is moving, I can get it to ohm out. No worries here, I never run the car less than a quarter tank anyway. (I bought a new sensor to be safe and it did the same exact thing so I think the sensors good).

But when I tip it, I still get a “Low Fuel” alarm on the display and the tank reads dead empty. I’m scared to continue to put the car together, as I have the whole drivetrain and subframe out of the car, and because the fuel level sensor doesn’t work I’m afraid the car will not start if I reassemble everything if it can’t read fuel level. I can live without a fuel gauge(don’t really want to) but I don’t want to tear the whole car down again.

So my questions are, what else can I check?
Is the fuel pump wiring harness wired correctly(meaning is that OEM ground just taped off because the new fuel pumps are grounded through the FC3?

The cars stuck until I get this figured out and I was hoping to close it all up before winter hits but I’m running out of time. Please let me know anything else I can check, I’ve ran out of options from what I could find.

Thanks,
Dylan

 

The sensors should have valid resistance through their full range of motion.

Remember at a quarter tank indicated, your right tank may be empty.

Measure the resistance across the wires from each sensor. What is the value of each with the tanks right side up, the value of each with the tanks upside down, and the model year of your C6?

 

On the Fore system the float has a lot more opportunities to get caught on wiring and in tank fuel lines. Also check the clocking on the whole hat assembly. Mine was about 10* off from where the front facing arrow should be which caused the float to hit something.

 

Short post guys, this was resolved. It was multiple wiring issues car-side which made it hard to trace in addition to the weird resistance issue with the floats, I just installed and reinstalled the fore hanger 8 times for fun, hahaha. Thanks for the tips though guys!

 

What exactly was your fix for this? Installed fore dual pump with fc3 controller about to send it to get tuned and getting a service fuel system error and no fuel level. I tried swapping the level sensor wires just incase I got them backwards with no luck. P0463 is the code that keeps coming up, car has at least 10 gallons if fuel so I know both tanks have fuel just don't want this to delay my tuning. Fuel pressure reads grood and have no issues other than the warning and code.