KN - Testing Notes

NOTE: You should enter this Pinpoint Test only when you have been directed here from Quick Test.


REMEMBER


To prevent the replacement of good components, be aware that the following non-EEC areas may be at fault.

- Damaged fuel pressure regulator

- Damaged Vacuum hoses

- Engine operating hoses

- Base Engine (valves, vacuum leaks, timing, etc.)


This Pinpoint Test is intended to diagnose only the following:

- FPRC solenoid

- Harness Circuits: FPRC, and VPWR

- Processor assembly


DESCRIPTION


The Fuel Pressure Regulator Control (FPRC) solenoid controls the vacuum applied to the fuel presure regulator. The FPRC solenoid contains a valve with two ports. One port is connected to manifold vacuum. The second port is connected to the fuel pressure regulator. The FPRC solenoid also has an air filter cap (vent) on it. If the solenoid is energized, then the solenoid valve closes the vacuum path to the second port which leads to the fuel pressure regulator. This results in a higher fuel pressure during crank, idle, neutral and wide open throttle drive modes for a predetermined time and engine temperature. If the solenoid is not energized, then the solenoid valve opens the vacuum path to the second port, allowing manifold vacuum signal to be applied an input to the fuel pressure regulator.