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Showing results for tags 'fueling'.
My new to me 2017 2500HD Denali Duramax would not accept fuel. I had to fill it ever so slowly to prevent backlash and spewing fuel all over the place. It was obvious to me that the vent was not venting. I shot compressed air into the vent line and determined that it was not clogged with a dirt dauber or anything like that. I traced the line to the top of the fuel tank....it does not appear to be kinked TOO badly at the top of the tank (but a 90 degree fitting sure would have been a nice touch GM). Best I can tell, when the truck is full of fuel, fuel can slosh up into the filler neck and back flow down in the vent hose which happens to be about 4" longer than it really needs to be. This allows fuel to get trapped in the sag and prevents air from entering the fuel tank. I shortened the vent hose 3.5", re connected it at the filller neck and zip tied it to the filler hose so that it will not be able to sag. Problem solved, It can take fuel at full pressure now. Hope this helps the next person that has this problem.