mattRS

a few days ago my fuel system started to screw up. you know how when you are low on gas and turn, it starts boggin? it does that every once in a while now, when im goin straight. happens all the way from 1-80 mph. i have enough pressure in my tank that when i take off the gascap it gives a whoosh noise. also, i changed the filter and put in cleaner a few days ago. i was told i might need a pressure regulator rebuild kit. by the way, its TBI. what do yall think?

Vader

Matt,

The first thing I would do is to perform a fuel pressure test. The test can identify whether the problem is fuel related at all, and whether is is the pump or regulator. On a TBI engine, you'll need to install an adapter to provide a test fitting. Normal fuel pressure should be betewen 11-13 PSIG.

mattRS

i am guessing if the FP is fine before it hits the TB, its the regulator?

Vader

Matt,

If the fuel pressure is low, it will be low through the entire system. The only exception to that would be in the case of a clogged filter, where the pressure differential across the filter would cause lower pressure at the TB and regulator. The regulator is an integral part of the system, and if it doesn't control the pressure correctly, pressure will be low both at the pump and TB. Conversely, if the pump cannot produce adequate pressure, the regulator cannot raise or "regulate up" that pressure.

The first thing to do is get an accurate measurement of the pressure. If the pressure is lower than it should be, you then need to determine the cause. If the pressure is indeed low, you can crimp the fuel return line from the regulator to determine if the regulator is leaking through, or if the pump cannot produce adequate pressure. With the regulator return line crimped closed, the pump should be able to produce at least 30 PSIG. If the system pressure does not increase with the regulator return line closed, the pump is suspect.