failure to start after warmed up - ZR-1 Net Registry Forums

QB93Z · 04-09-2017

Fuel rail pressure is a variable. The system is designed for a constant pressure differential across the injector. The pressure in the Intake Plenum varies with throttle position, from high vacuum at idle to atmospheric pressure at full throttle. Therefore the Fuel Pressure Regulator is connected to plenum vacuum and adjusts fuel rail pressure to follow the changes.

As a rough check fuel pressure varies from 40 to 50 psi under normal conditions. The highest pressure you would see is with fuel pumps running, engine off, Ign ON/Engine OFF.

The Field Service Manual gives exact parameters for testing and evaluating the FPR.

Jim

04-09-2017	#11
QB93Z Join Date: May 2007 Location: Westminster, Maryland Posts: 3,689	Re: failure to start after warmed up Fuel rail pressure is a variable. The system is designed for a constant pressure differential across the injector. The pressure in the Intake Plenum varies with throttle position, from high vacuum at idle to atmospheric pressure at full throttle. Therefore the Fuel Pressure Regulator is connected to plenum vacuum and adjusts fuel rail pressure to follow the changes. As a rough check fuel pressure varies from 40 to 50 psi under normal conditions. The highest pressure you would see is with fuel pumps running, engine off, Ign ON/Engine OFF. The Field Service Manual gives exact parameters for testing and evaluating the FPR. Jim