In a 2G engine bay, there are three solenoids located on the firewall. These solenoids are somewhat scattered near the center-driver side area of the firewall. From left to right, as if standing in front of the car and looking at the engine bay:
- EGR Control Solenoid
- Purge Control Solenoid
- Fuel Pressure Solenoid
The left-most solenoid of the three is the EGR (Exhaust Gas Recirculation) Control Solenoid. This is part of the emissions system and it allows some unburned exhaust gases to flow through the EGR Valve and back into the intake system. The EGR valve is bolted to the bottom of the intake manifold, beneath the throttle body.
Both the EGR solenoid and the EGR valve can be removed from the vehicle along with any other part of the emissions system. The EGR solenoid can be easily removed from the firewall. Once you remove the solenoid, follow the vacuum lines and put rubber vacuum caps on the other ends where the vacuum lines once connected (ie. EGR valve, throttle body, etc.).
The next solenoid, to the right of the EGR solenoid, is the Purge Control Solenoid. The main function of the purge control solenoid is to link the charcoal canister to the intake system. The charcoal canister (located beneath the battery, near the fuel filter) is designed to absorb and trap any fuel vapors that comes from the fuel tank. The purge control solenoid then allows the vapors to travel from the charcoal canister and into the intake system where they are then burned off for emissions purposes.
You can remove this purge control solenoid from the firewall as well, applying caps where the vacuum lines once connected to. Generally, you will remove this when removing the charcoal canister.
The last of the three solenoids, shown in yellow, furthest to the right, is the Fuel Pressure Solenoid (FPS). The only function that the FPS has is to allow the ECU to temporarily raise the fuel pressure on hot starts by blocking off the vacuum to the fuel pressure regulator (FPR).
This can be removed as well and will not hurt your car any, other than possibly a fraction of a second difference in starting your engine when it is still hot. But, you won’t even notice a difference. This is also a common place to tap into for your boost gauge by cutting the correct vacuum line and adding a “T”, then reconnecting the cut vacuum line to the “T” and adding the extra hose to the new boost gauge.
If you want to remove your FPS, you would then run your aftermarket boost gauge by tapping into the vacuum hose between the intake manifold and FPR.