Ken K
I'm Awesome
GM's specs show fuel pressure for the CSFI system as 56 - 62 PSI / 385 - 430 kPa. The poppet valve is mechanically un-seated with fuel pressure when the fuel injector valve is opened electrically at the fuel body, therefore the fuel line pressure is more important.
Also the accuracy of the fuel gauge being used. While the poppet injector opens at 58 PSI and sprays until pressure drops after the electric valve is seated, it stops spraying at 55 PSI.
This poppet system is "Central Sequential Fuel Injection" and pressure is very important. Each injector over time, will open or close at different pressure points. If they stick shut, high pressure procedures using GM equipment and nitrogen opens a stuck injector. If it can not open, it can not be cleaned.
The up-dated or 2nd design is multec high impedance injector which is not effected by actual line pressure, referred to as "MPFI". The disc design is located a distance from the directional spray plate and helps eliminate carbon build up.
Vacuum hold line pressure to 60, but increases to 62 PSI when absent during WOT as atmospheric pressure floods the intake. This simply increase the amount of fuel delivery during the same injector on-time. This increase of fuel works to keep lean conditions from occurring, just like a accelerator pump shot inside a carburetor. Injector on-time is increased at the same time due to TPS and MAP inputs. O2 sensors report what they see after the suck, squash bang, blow occurs. Look at them as hydrocarbon sensors, as they produce more voltages when expose to more hydrocarbons in the exhaust stream.
In short, a good gauge with 56 - 62 should put you in the green, running poppet style injectors.
Providing there is no line pressure drop at higher RPM's as volume is required, otherwise loss of power or starving for fuel. Loss of volume can come from a restricted fuel filter, marginal fuel pump, restricted sock type tank filter on pump or pinched line...or act like it with a potato in the tailpipe.
Also the accuracy of the fuel gauge being used. While the poppet injector opens at 58 PSI and sprays until pressure drops after the electric valve is seated, it stops spraying at 55 PSI.
This poppet system is "Central Sequential Fuel Injection" and pressure is very important. Each injector over time, will open or close at different pressure points. If they stick shut, high pressure procedures using GM equipment and nitrogen opens a stuck injector. If it can not open, it can not be cleaned.
The up-dated or 2nd design is multec high impedance injector which is not effected by actual line pressure, referred to as "MPFI". The disc design is located a distance from the directional spray plate and helps eliminate carbon build up.
Vacuum hold line pressure to 60, but increases to 62 PSI when absent during WOT as atmospheric pressure floods the intake. This simply increase the amount of fuel delivery during the same injector on-time. This increase of fuel works to keep lean conditions from occurring, just like a accelerator pump shot inside a carburetor. Injector on-time is increased at the same time due to TPS and MAP inputs. O2 sensors report what they see after the suck, squash bang, blow occurs. Look at them as hydrocarbon sensors, as they produce more voltages when expose to more hydrocarbons in the exhaust stream.
In short, a good gauge with 56 - 62 should put you in the green, running poppet style injectors.
Providing there is no line pressure drop at higher RPM's as volume is required, otherwise loss of power or starving for fuel. Loss of volume can come from a restricted fuel filter, marginal fuel pump, restricted sock type tank filter on pump or pinched line...or act like it with a potato in the tailpipe.
