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You should have a test port on the Fuel Supply rail, use a tool from a local auto parts "Tool Loaner program" where you can borrow tools for free,w/a deposit of course,then follow the steps provided;
MPI Fuel System Pressure Test
The MPI fuel system used in vehicles equipped with a 4.OL engine employs a vacuum balanced pressure regulator. Fuel pressure should be approximately 55-69 kPa (8-10 psi) lower with the vacuum line attached to the regulator than with the vacuum line disconnected. System fuel should be 214 kPa (31 psi) with the vacuum line connected to the regulator and 269 kPa (39 psi) with the vacuum line disconnected. CAUTION: Some fuel may be discharged when connecting fuel gauge to fuel rail.
Connect a 0-414 kPa (0-60 psi) fuel pressure gauge to test port pressure fitting on fuel rail (Fig. 7).
Remove vacuum line from pressure regulator.
Start the vehicle.
Note gauge reading. With vacuum line disconnected, fuel pressure should be approximately 269 kPa (39 psi).
Connect vacuum line to pressure regulator. Note gauge reading. Fuel pressure should be approximately 214 kPa (31 psi).
If fuel pressure is not approximately 55-69 kPa (8-10 psi) higher with vacuum line removed from regulator, inspect pressure regulator vacuum line for leaks, kinks or blockage. CAUTION: Fuel pressure will rise to as much as 655 kPa (95 psi) when the fuel return tine is pinched shut, shut engine down immediately after pinching oft fuel return line.
If fuel pressure is low, momentarily pinch shut the hose section of the fuel return line. If fuel pressure remains low, inspect the fuel supply line, fuel filter, and fuel rail inlet for blockage. If fuel pressure rises replace fuel pressure regulator.
If fuel pressure is above specifications, inspect the fuel return line for kinks and blockage.
Remove the cap from the pressure test port in the fuel rail.
Connect a 0-414 kPa (0-60 psi) fuel pressure gauge to the pressure fitting on the fuel rail (Fig. 7).
Start the vehicle. Pressure should be approxi- mately 214 kPa (31 psi) with the vacuum hose connected to the pressure regulator and 269 kPa (39 psi) with the vacuum hose removed from the pressure regulator.
If the pressure is not to specification, check the following before replacing the fuel pressure regulator:
4a - Inspect the fuel supply and return lines/hoses for kinks or restricting bends
4b - Check the fuel pump flow rate. A good fuel pump will deliver at least 1 liter of fuel per minute with the fuel return line pinched off. If the fuel pump does not pump adequately, then inspect the fuel system for a plugged fuel filter or fuel pump inlet filter (sock). Fuel pump flow rate can be done by connecting one end of an old A/C gauge hose to the fuel test port on the fuel rail and inserting the other end of the hose into a container of at least 1 liter capacity. Run the fuel pump by installing a jumper wire into diagnostic connector terminals D1-5 and D1-6. Be sure to pinch off the fuel return line or most of the fuel will be returned to the fuel tank.
If the fuel pump(s) run while the pressure is falling, replace the fuel pressure regulator and (although I'm sure you've already done this), replace the fuel filter. If the fuel pumps appear to be turning off by themselves, replace the inertia (fuel cutoff) switch.
It drops when it is turned off through the return the pump might be getting weak If you keep using the starting fluid you will blow the intake off of it or it will get hooked on it and won't start without it.
Check fuel pressure wit a guage at schrader valve on fuel rail with key on and engine not running. The pressure needs to be 55 to 61 PSI. If it is less than 55 PSI, replace the fuel pump in gas tank and fuel filter. If it is more than 61 PSI, replace fuel pressure regulator.
Hello , fuel pump relay location is in the relay box by the radiator. The fuel psi regulator is on the fuel rail itself. The regulator looks like a small disk about 1.5inchs in dia. It will have a vacuum line running to it.
First you need to have your fuel system tested. It sounds as though the relay and pump have gone out. When you turn the ignition to on the pump should energize for 2 seconds and stop. The pump will deliver fuel after startup. Poor performing pump equals poor performing vehicle. With the vehicle not staying running when it did start, I would check the fuel pressure and then replace the pump. You can check the fuel pressure regulator by pulling off the vacuum line and see if you have fuel in the line. If you do the regulator is shot. The fuel pump relay also needs to be checked for operation especially if the fuel pump is not working. Also check your rollover valve to be sure it has not tripped.
in the fuel tank , MIninum fuel pressure for the vehicle if it has a vortec engine is 60 PSI the vehicle will not run on less than 60PSI
If you have a non vortec engine the fuel pressure is around 9 PSI
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