so the last post in this thread on 11/19/2014. did you ever get it figured out? (reviving an old post but this is the problem i'm having.) i've got an 08 suburban w/LMM. i'm guessing my secondary tank is not working because my last 2 fill-ups have only taken 24-ish gallons (roughly the size of the primary tank only) AND gas won't run into the filler hole at anything but a painfully slow rate when i'm re-fueling so i'm guessing the secondary tank pump is not activating and the tank is staying full and also preventing normal filling.
