Evoguy!123

hello.

i want to know what exactly this is also had a code p0090 Fuel Pressure Solenoid Circuit i just got a evo 8 like 3 months ago and so i found a broken solenoid believe its EGR vacuum replaced it and still did the same low RPM idle. i want to know whats a Fuel Pressure Solenoid Circuit i don't really know about evo so i am learning little by little. help me out guys. thank you

barneyb

The fuel pressure solenoid, when operated by the ECU, vents the fuel pressure regulator to atmosphere. The fuel pressure solenoid is actuated at hot start. At start, since the manifold, with throttle closed, will contain vacuum, this vacuum normally lowers fuel pressure. Venting the fuel pressure regulator to atmosphere raises the fuel pressure, preventing vapor lock. Without looking at a diagram I'd guess the ECU provides a ground to activate the fuel pressure solenoid and looks at that ground to see if current is flowing. If no current it sets a code.

During normal use the solenoid is not activated so look for the cause of your idle problem elsewhere.