Fuel pressure regulator had no vacuum line connected

If you are getting Fuel in the vacuum line, it sounds like you could have a bad fuel pressure regulator. Check the line that comes off the Fuel pressure regulator. use a hand vacuum pump see if fuel is being pulled out of the regulator.Replace regulator if you find fuel
coming from that vacuum port.

Thinking fuel pressure regulator,it has a vacuum line connected to it,if the regulator diaphram ruptures it vacuum pulls raw fuel into the line.

Too much gas. Maybe the fuel pressure regulator has failed. Pull off the vacuum hose to the regulator-if any evidence of gas in the vacuum line, regulator is bad-diaphragm has ruptured and letting in extra gas to engine through the vacuum line.
If that is good, no gas in vacuum line, have the fuel pressure checked. Still possible the regulator is not right.
Watch the pattern of gas out the bottom of injectors while the engine is cranked. Should see a fine mist cone pattern spraying out from the injectors. If it is just dripping, injectors may be clogged.

If it's vacuum operated, the regulator would be on your fuel rail. It would have a fitting/nipple for the vacuum line to connect to. The line would come from the intake manifold, somewhere, but a vac. line specific for the regulator. Some cars use means other than vacuum to regulate fuel pressure. Some even have the pressure regulator in the tank with the pump. Not exactly sure about your '97 blazer.I hope somebody else here knows.

First check your fuel pressure regulator by pulling the vacuum line off and check for fuel there should not be any.Then start the car and with a pressure gauge hooked up to fuel rail pull the vacuum line off the pressure should rise 5-10 psi if it does'nt replace regulator.Next check the fuel pressure it should be 41-47 with key on and engine off if not within specs replace fuel pump.

usually caused by busted diaphram in fuel pressure regulator allowing fuel to be drawn thru regulator directly to intake manifold. Pull vacuum line off regulator, plug line with golf tee, start car and watch to see if gas comes out of regulator. If yes, turn off car, replace regulator. The regulator sits near the fuel rail on the top of the engine as shown below. I will paste replacement instructions below from autozone.com in case you need to replace the regulator. Please let me know if you have any questions.

Removal & Installation

4.2L Engine

1. Relieve the fuel system pressure.
2. Remove the air cleaner outlet resonator.
3. Disconnect the engine wiring harness from the retaining clips at the front of the engine.
4. Disconnect the fuel pressure regulator vacuum line.
5. Clean any dirt from the fuel pressure regulator and the surrounding area.
6. Disconnect the fuel return pipe.
7. Remove the fuel return pipe retainer.
8. Remove the fuel pressure regulator retainer.
9. Remove the fuel pressure regulator.
10. Inspect the regulator filter screen for contamination. If contaminated, replace the fuel pressure regulator.

To install:

1. Install the regulator filter.
2. Install the new O-ring on the fuel pressure regulator.
3. Lubricate the fuel pressure regulator O-ring with clean engine oil.
4. Push the fuel pressure regulator into the regulator housing on the fuel rail.
5. Install the fuel pressure regulator retainer. Tighten the regulator retainer screw to 71 inch lbs. (8 Nm).
6. Install the fuel return pipe retainer. Tighten the return pipe retainer screw to 71 inch lbs. (8 Nm).
7. Connect the fuel return pipe.
8. Connect the fuel pressure regulator vacuum line.
9. Connect the negative battery cable.
10. Inspect for leaks:
    1. Turn ON the ignition for 2 seconds.
    2. Turn OFF the ignition for 10 seconds.
    3. Turn ON the ignition.
    4. Inspect for fuel leaks.
    
    
11. Install the engine wiring harness into the retaining clips at the front of the engine.
12. Install the air intake resonator.

Removal & Installation of fuel Regulators on
4.8L, 5.3L & 6.0L Engine To Remove:
CAUTION
Three styles of fuel pressure regulators and fuel rails will be used in this model year. Each regulator has a different "footprint" that consequently changes the size of the receiving port in the fuel rail. The regulator retaining clips are specific to each rail-regulator design and cannot be interchanged.

1. Remove the engine sight shield.
2. Relieve the fuel system pressure. Refer to Fuel Pressure Relief Procedure.
3. Clean the fuel pressure regulator retainer and the surrounding area.
4. Remove or disconnect the following:
   • Fuel pressure regulator vacuum line.
   • Fuel pressure regulator retainer.
   • Fuel pressure regulator.
5. Remove the following parts from the fuel rail:
   • Backup ring (10)
   • Regulator Seal O-ring (11)
   • Regulator filter (12)
   • Regulator seal O-ring (13)

To Install:

1. Make sure the NEW fuel pressure regulator retainer is the right one.
2. The tabs (1) are used on the straight vacuum port retainer (2), and the E85-straight vacuum port retainer (3).
3. The angle vacuum port retainer (4) has no tabs.
   
   
4. Install the following parts onto the fuel pressure regulator (9).
   • Backup ring (10)
   • Regulator seal O-ring (11)
   • Regulator filter (12)
   • Regulator seal O-ring (13)
5. Lubricate the fuel pressure regulator O-rings with clean oil.
6. Install the fuel pressure regulator and retainer. CAUTION
   Whenever the fuel pressure regulator is removed from the fuel rail NEW O-rings and a NEW retaining clip should be used on reinstallation.
   
7. Connect the vacuum line.
8. Tighten the fuel filler cap.
9. Use the following to inspect for leaks:
   • Turn ON the ignition, with the engine OFF, for 2 seconds.
   • Turn OFF the ignition for 10 seconds.
   • Turn ON the ignition, with the engine OFF.
   • Install the engine sight shield.

8.1L Engine To Remove:
Fuel pressure regulator vacuum line

1. Before servicing the vehicle refer to the precautions at the beginning of thjs section
2. Remove the fuel injector sight shield as needed
3. Relieve fuel system pressure (See: Fuel Pressure Relieving)
4. Disconnect the fuel pressure regulator vacuum line (A) 8.1L Fuel pressure regulator retainers
   
   
5. Clean any dirt from the fuel pressure regulator retainer and the surrounding area
6. Remove the fuel pressure regulator retainer (I)
7. Remove the fuel pressure regulator (H) from the fuel pressure regulator housing

To Install:
8.1L Fuel pressure regulator retainers

1. Install or connect the following:
   • Backup ring (J) on the fuel pressure regulator (H)
   • New large O-Ring (K) on the fuel pressure regulator
   • Regulator filter (L) on the fuel pressure regulator
   • New small O-Ring (M) on the fuel pressure regulator
2. Lubricate the fuel pressure regulator large O-Ring and the small O-Ring with clean engine oil
3. Push the fuel pressure regulator onto the regulator housing on the fuel rail
4. Install a new fuel pressure regulator retainer (I)
5. Install or connect the following:
   • Fuel pressure regulator vacuum line
   • Negative battery cable
6. Tighten the fuel filler cap
7. Inspect for leaks using the following procedure:
   • Turn on the ignition with the engine off for two seconds
   • Turn off the ignition for 10 seconds
   • Turn on the ignition with the engine off
   • Inspect for fuel leaks
8. Install the fuel injector sight shield
9. Road test the vehicle to check performance

Release fuel pressure by removing fuel pump relay and turning engine over to release pressure. Place a rag to catch any fuel under regulator Fuel pressure regulator has a locking clip pry clip off remove vacuum line pull regulator out with twisting motion,replace fuel pressure regulator install clip connect vacuum line install relay. Check for leaks,your done.

GM Century/Lumina/Grand Prix/Intrigue 1997-2000
Fuel Pressure Regulator - Removal & Installing
The fuel pressure regulator is a diaphragm-operated relief valve with fuel pump pressure on one side and regulator spring pressure and intake manifold vacuum on the other side. The regulator's function is to maintain a constant fuel pressure across the injectors at all times. The pressure regulator compensates for engine load by increasing fuel pressure as engine vacuum drops.

The fuel pressure regulator is serviced as a separate component. When servicing the pressure regulator, make sure that the O-ring back-up, large O-ring, filter screen and small O-ring are properly positioned on the pressure regulator.


Fig. Cutaway view of a typical fuel pressure regulator


REMOVAL & INSTALLATION
The need to work as cleanly as possible cannot be over-emphasized. Even the smallest amount of dirt, if allowed into the fuel pressure regulator and/or the fuel rail, will find its way to the fuel injectors. The nozzle openings of the injectors are very small. Keep hands and tools clean. Clean the areas to be disconnected with a suitable solvent. Carefully cover open fittings and connections to keep out foreign material. Dirt in the injectors almost guarantees a clogged fuel injector and engine performance problems.
3.1L and 3.4L (VIN E) Engines

1. Disconnect the negative battery cable.
2. Relieve the fuel system pressure using the procedures found in this section.
3. Remove the upper intake manifold assembly. Please see .
4. Disconnect the vacuum line from the pressure regulator.
5. Remove the regulator retaining screw and remove the retainer bracket. Using a clean shop cloth to catch fuel spillage, carefully pull the regulator from the fuel rail. Twist the regulator slightly while removing to ease removal. Discard the O-ring.

Fig. Exploded view of the fuel pressure regulator mounting-3.1L and 3.4L (VIN E) engines
To install:

1. Clean all parts well. DO NOT use shop compressed air to test or clean a fuel pressure regulator. Clean the fuel pressure regulator screen, if necessary. DO NOT immerse the fuel pressure regulator in a solvent bath or it will be damaged.
2. If the filter screen has been contaminated, it should be removed and the pressure regulator replaced.
3. Lubricate a new pressure regulator O-ring with clean engine oil and install on the regulator inlet.
4. Install the fuel return pipe to the regulator.
5. Install a new retainer and spacer bracket into the slot on the fuel rail and install the pressure regulator to the fuel rail. Tighten the fuel return line nut to 13 ft. lbs. (17 Nm).
6. Connect the vacuum line to the pressure regulator and install the retainer screw. Tighten to 76 inch lbs. (8.5 Nm).
7. Inspect and verify that the retainer and spacer bracket is engaged in the slots in the fuel rail. Grasp and pull on the regulator to ensure that it is properly seated.
8. Install the upper intake manifold. Please see .
9. Connect the negative battery cable.
10. Inspect for leaks using the following procedure:
    • Turn the ignition switch to the ON position for 2 seconds.
    • Turn the ignition switch to the OFF position for 10 seconds.
    • Turn the ignition switch to the ON position again.
    • Inspect all areas for fuel leaks.

Other size engine can find in autozone.com (free register).

Hope this help (remember rated this).

Bad fuel pressure regulator. Located on drivers side of engine on fuel rail. Cost of part is around $70. Easy to replace. Buy the part, look at it, find the old one on the engine in the area described above. Pull the vacuum line off of it, if you see any fuel in the vacuum line it's bad. The vacuum line sucks up the fuel flooding the engine. Classic symptoms. Make sure to relieve the fuel pressure prior to removing or let it sit for a couple of hours, or over night. The leak will relieve the pressure over time. Simple clip holds it on, easy to get at. Make sure to remove both "O" rings prior to putting new unit on. Should solve the problem.