Originally Posted by
Throbbinhood
My LRA tank act's as a sub. I wired it into the original gauge with a switch, idea being to switch between the tanks, but it's never been accurate. I just wait until I'm at 1/4 on the main tank and then start the transfer, not that that helps you much. From what I've read, and I could be wrong, the sender works off an ohm reading or resistance or something. Since modifying my wiring (adding the switch), my main tank reads slightly lower than normal. If what I've read is correct, I'm guessing I've added more resistance using the switch and crimps/joins. At a guess, yours may suffer from the same inaccuracy if your wiring has been cut/joined etc. Hope someone that knows a bit more about the fuel gauges in these could advise further as I'm honestly not 100%.