Originally Posted by
Neukam
Not being vacuum referenced shouldn't cause any problem under light loads or without a restriction in the intake. The job of the fuel pressure regulator in any fuel injection system is to maintain a constant differential between the pressure inside the fuel injector (fuel line, fuel rail, etc) and the pressure outside the fuel injector (throttle body, intake manifold, etc). Because the fuel injector nozzles are not subjected to manifold vacuum, the fuel pressure regulator should not be referenced to manifold vacuum. The factory fuel pressure regulator was located on the throttle body, within the air cleaner, and near the fuel injectors so that it can reference the pressure near the injectors and maintain that constant pressure differential. The aftermarket pressure regulator should be similarly referenced. By referencing the area near the injectors, the system will be able to compensate for any intake/air cleaner restriction, dirty air filter, atmospheric pressure changes, etc.
A 3 wire sensor still references to the exhaust pipe that it is installed to. These systems have a dedicated ground for the O2 sensor. It should be a tan wire. if I remember correctly, its usually attached to the back of the right cylinder head. If that ground wire is compromised, the ECM will not read the O2 sensor properly, will assume the engine is running lean, and will force the engine richer. Make sure that the O2 sensor heater (or anything else) is not grounded through this tan wire and that it is properly attached and making a good electrical connection.
I saw a guy install a fuel filter backwards once. The truck ran like dookie for about 2 weeks, before it stopped running altogether. Just something else to check.
Bookmarks