GM 5.3 GDI Running Rich? Could Be A Leaking HPFP

Easy way to tell if there is gas getting into the crankcase from a leaking high pressure fuel pump seal. This applies to any GDI engine.

[@mohamedalabadi109]

Bro i need your help 🙏 i have a 2016 sierra 5.3 1500 4wd , it has a crazy fuel consumption , with no codes , also it has a slight misfire on low throttle , no one in my county knows the reason , not even the dealer 🫤

[@marelmaynard77]

2014 gmc Sierra 5.3 missing only after engine warms up. Nobody has been able to figure it out.

[@matthewstrickland310]

Had a HPFP changed for fuel in the oil a little over 1000 miles ago. How long will the smell of fuel stick around on the dipstick?

[@TechnicianRed]

Did you have the oil changed when that pump was changed? If not, you need to change that oil!

[@bosskopo15]

Is it possible to differentiate between a high pressure fuel pump leak like this and an injector leak on a GDI?

[@TechnicianRed]

Yes. A fuel pump leak can be isolated by capping the PCV line and watching fuel trims like in this video. If you have a leaking injector capping the PCV won't make any difference in fuel trims.
Also, a leaking GDI injector will cause the fuel rails to lose pressure quicker than normal when you shut off the engine. My fuel pressure gauge has a ball valve where I can isolate the fuel rails from the fuel line to see if pressure bleeds off to confirm an injector is leaking.
Also, every GDI engine I have worked on (mainly GM and Ford) allows you to do an injector flow test with a scan tool. If an injector is leaking it should fail that test.