Repairs

Fuel Pressure Regulator

The fuel pressure regulator (FPR) is the small metal can in front of the intake manifold on the centerline of the engine with a vacuum hose coming out the top. This vacuum signal is controlled by a vacuum solenoid located beside the ignition coil on the driver's side fender. The vacuum is on at all times except for hot starts, when the vacuum signal is removed from the FPR, raising fuel pressure and making hot starts easier. The regulator is nothing more than spring loaded diaphragm, the spring keeping the appropriate amount of pressure in the fuel system. The fuel flows from the fuel pump into the injector rail(from the rear) and the regulator bleeds pressure off the front of the rail and returns it back to the fuel tank. The only real way the regulator will fail is when the diaphragm gets old and cracks. The easiest way to check for this is to pull the vacuum hose off the top of the regulator and rev the engine. If the regulator is bad, fuel may squirt out the vacuum port, meaning the diaphragm is broken. When the diaphragm fails, fuel is sucked into the intake and the engine runs extremely rich, making a bluish smoke in the morning. Some of this leaking fuel will get sucked into the crankcase through the PCV system, making your oil smell like gas. Bad pressure regulators should be changed as soon as possible because the extra fuel can make the engine backfire through the intake, which can kill the air flow meter. To change the pressure regulator, simply remove and replace it by removing the two screws and disconnecting the fuel lines and temperature sensor wire. Make sure you de-pressurize the fuel system first or you'll spray gas everywhere when you remove the fuel lines.

 
repairs/fpr.txt · Last modified: 2014/09/08 18:05 (external edit)
 
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