One of the headaches I’ve been dealing with since I got the truck back from TX is the slow (re)fuel syndrome. I’m hoping it’s not a leaking carbon canister that’s left activated carbon pellets in the pollution control system lines.
I ordered a new vapor canister vent valve assembly and the harness adapter. GM made the NNBS harness obsolete, this the adapter is needed.
GM Genuine Parts 19257603 Vapor Canister Vent Valve Solenoid Jumper Wiring Harness
ACDelco 20995472 GM Original Equipment Vapor Canister Vent Valve
They were $35.98 & $19.94 with free shipping off Amazon. Both are OEM GM parts. I wasn’t up to doing the install with a raging cold and nose raining like a waterfall. The diesel indi tech did the job for $135.
The results. It didn’t cure the slow refuel issue but definitely helped. I’d say about 50-60% better when doing its 1st refuel yesterday. I’ll update after a few more e85 fill ups.