That thingie on my manifold

[Mark52]

Several of us autocrossers were looking at my engine at the ER event Sunday. I pointed to a thingie mounted on my intake manifold and asked what it is/does since I've apparantly been running most of the year with one of the vacuum tubes disconnected. The Enthusiasts Manual says it is a PRC or Presure Regulator Control solenoid valve. "This device monitors manifold vacuum and controls the operation of the fuel pressure regulator so that fuel pressure is kept within desirable confines for the operating conditions prevailing. To prevent the percolation of fuel when a hot engine (coolant at 194 F or above) is restarted in a hot climate(158 F +) and allowed to idle, the PCM (or ECU) operates thr PCR valve for 150 seconds. During this time, manifold vacuum is shut off, allowing fuel pressure to rise to 41 psi." So, up until Sunday I've been running around with slightly higher fuel pressure (41 vs. 32-3. Would the slightly higher pressure help or hinder the performance of the engine?

[altiain]

Unless it also alters the injector pulsewidth to account for the higher fuel pressure, it is probably just making you run pig rich.

[POS Racing]

.....To prevent the percolation of fuel when a hot engine (coolant at 194 F or above) is restarted in a hot climate(158 F +) and allowed to idle, the PCM (or ECU) operates thr PCR valve for 150 seconds.

Us Classic Cadillac guys call that percolation Vapor Lock! My 'lac has done this trick, you can actually watch the fuel boil out of the fuel filter (which is housed in a glass bowl). And the car will not start up until she cools off or you give it some ether.

I'd leave it hooked up if I were you it sounds like a good thingie.