Replaced bad fuel pump, installed new relay and fuel filter, engine turns over but is not firing on..... positive the fuel pump is pumping gas and checked to see if gas was going thru fuel filter. Tried small amount of gas and start fluid to engine to start. It still wont "fire" on. Not sure what to check next? changed distributor cap and spark plugs less than ten thousand miles ago?

disconnect the fuel line near the engine (usually at the throttle body assembly) and turn the key to ..run..position..listen for a buzzing of the pump..if you dont hear it or see liquid shooting out of the fuel line..theres no power to the pump or it may be bad..if it comes on but no fuel..be looking at the filter under the car by the front of the gas tank.. it may be plugged up..you can also check the pump for operation by powering it up manually at the pumps connector near the gas tank..if it works there..there is an auto shutoff relay that controlls the pump and the ignition.. it may be bad also..

NEED HAVE VECHICLE CODE SCANNED FIRST LOOK FOR FAULT CODES MANY THINGS WILL CAUSE NO STARTING,LIKE BAD CRANKSHAFT POSITION SENSOR.FAULTY CAMSHAFT POSITION SENSOR,BAD SPARK PLUGS FOULED OUT BY FLOODING ENGINE DUE TO LEAKING FUEL INJECTORS,BAD ENGINE COOLANT TEMPERATURE SENSOR,BAD MASS AIR FLOW SENSOR.FAULTY ECM. CODE SCAN VECHICLE FIRST.IF NO FAULT CODES CAME UP YOU COULD HAVE FAULT IN FUEL SYSTEM, COULD HAVE STOPPED UP FUEL FILTER,BAD FUEL PUMP RELAY OR FUSE THE FUEL PUMP COULD BE FAULTY. TURN IGNITION SWITCH TO ON POSITION LISTEN FOR FUEL PUMP OPERATION IN FUEL TANK, YOU SHOULD HEAR FUEL PUMP RUN FOR FEW SECONDS THEN TURN OFF.IF NO FUEL PUMP BAD MORE LIKELY BUT CHECK FUSE AND RELAY FIRST BEFORE BUYING NEW FUEL PUMP.DONT BUY NEW PARTS HAVE VECHICLE CODE SCANNED FIRST USING DIAGNOSTIC SCANNER YOU COULD HAVE BAD CONTAMINATED FUEL.

Several months could be a tank of bad gas. When turning the ignition to on position the pump runs for 3 to 5 seconds to pressurize the system, next find the valve on fuel rail and press it, Shield with a rag while doing this. You should get fuel. Check the way it smells, bad gas has an awful smell that can make you hurl! Attach a fuel pressure tester, it should be around 50lbs. If it's bad empty the tank by pressing the needle and relieving the pressure. Next disconnect fuel line before the filter get a container to catch the gas. IN the engine conpartment disconnect the fuel pump relay and put a jumper wire to run the pump until tank is drained. Instal new filter and pump if needed and add a can of "Seafoam" to the tank with fresh gas. Run pump until there's fuel at the fuel rail then put relay back in. now we should have ignition and constant running. Hope this helped.

If you change the fuel filter and still not getting fuel to the engine, then the other possible problems are:
- Clogged fuel lines due to 'dirty' fuel.
- Defective Fuel Pump which may not provide enough pressure to 'push' the fuel pass your new filter.

Hope it helps.

Keep in mind that you have several components there:
- Fuel Pump Sender Assembly,
- Fuel Pressure Regulator,
- Fuel Rail Assembly, and
- Fuel Injectors.

1.- Fuel Pump (Sender Assembly) - TESTING
Refer to the accompanying charts for fuel pump diagnosis and testing.

The fuel injection system remains under pressure, even after the engine has been turned OFF. The fuel system pressure must be relieved before disconnecting any fuel lines. Failure to do so may result in fire and/or personal injury.



Fig. 3.1L engine OBD system check to be done before fuel pump relay circuit diagnosis




Fig. 3.1L engine fuel pump relay circuit diagnosis (1 of 2)




Fig. 3.1L engine fuel pump relay circuit diagnosis (2 of 2)




Fig. View of the fuel pressure test port (Schrader valve)-3.1L engine

A - 3.1L engine fuel system pressure test (1 of 4)
B - 3.1L engine fuel system pressure test (2 of 4)
C - 3.1L engine fuel system pressure test (3 of 4)
D - 3.1L engine fuel system pressure test (4 of 4)



Fig. The fuel pump/fuel sender module assembly is mounted in the fuel tank


2.- Fuel Pressure Regulator - REMOVAL & INSTALLATION

(the fuel pressure regulator, which is located on the fuel rail assembly)

NOTE: Before removing the fuel regulator assembly, place a clean shop towel under the regulator to catch any fuel drips

1. Properly relieve the fuel system pressure.
2. If not done already, disconnect the negative battery cable.
3. On the 3.1L engine, remove the intake manifold plenum, as outlined in .
4. On the 2.4L engine, remove the fuel rail. Refer to procedure earlier in this section.
5. Detach the vacuum line from the regulator.
6. Place a shop towel under the regulator to catch any fuel that may drip out. Unfasten the fuel pressure regulator retaining screw, then remove the regulator by twisting and pulling it from the fuel rail.
7. Remove and discard the O-ring seal. Inspect the filter screen for contamination and replace if necessary.
   

To install:

1. Prior to assembling the pressure regulator to the fuel rail, lubricate the new rail-to-regulator O-ring seal with clean engine oil.
2. Place the O-ring on the pressure regulator and install the pressure regulator to the fuel rail.
3. Install the retainer or coat the regulator mounting screws with an approved thread locking compound and secure the pressure regulator in place. Tighten the mounting screw to 76 inch lbs. (8.5 Nm).
4. If removed, install the fuel rail assembly to the engine.

WARNING The fuel return pipe must be connected before tightening the regulator retaining screw to prevent the regulator from rotating. Rotation of the regulator could damage the retainer and spacer bracket and lead to a fuel leak at the regulator inlet.

1. Connect the fuel feed line and return line to the fuel rail assembly, use a backup wrench on the fittings to prevent turning.
2. Attach the vacuum line to the regulator.
3. On the 3.1L engine, install the intake manifold plenum.
4. Connect the negative battery cable. Turn the ignition to the ON position for two seconds, then turn it to the OFF position for ten seconds. Turn again to the ON position and check for fuel leaks.

continue...

the fuel pump doesnt set off the check light recheck the connections at the fuel pump check for power to the connector also check the pump new doesnt mean not defective

There is not fuse for pump but a relay in the relay block. I do suggest jumping to see if pump turns on. Test voltage from ECM if needed. If voltage is to pump, then pump is shot. If not voltage, relay may be bad

Check the fuel pressure at the shredder valve. You should have 60psi to 65psi with the fuel pump primed and engine not running. Once the engine has been started, there should be a 5psi drop. Make sure the fuel filter has been replaced and that the fuel pump is making at least 60psi. Anything less or more then 65psi will not activate the fuel injectors, the other thing to is that the spider injection system on the vortec are know to go bad and you may have to replace the system. Good luck and keep me posted, be glad to help you get your S-10 running 100% again. 

1. Does the pump actually run (key on engine off) pump should run for 2 seconds and go off and can be heard if you listen at the filler neck with the gas cap removed)
pump not running - Check relay (replace if bad) check wiring/fusese

Pump runs... go on to #2...

2. check the gas guage. is the gauge reading in the normal area it would read in or is it way way off like WAY above full or way below empty? This is a sign the electrical connection at the pump is plugged in backwards and the pump is spinning the wrong way and not picking up the fuel... (This is easy to get plugged in backwards inside the tank when installing the new pump)

3. Check for feed, return and vent lines being installed wrong where they attach to the tank... they can easily be hooked up wrong and fuel is either pumped up in to the return line or pumped in to the fuel tank vent line..

4. check for kinked or crushed fuel lines from tank to engine.

5. check fuel pressure regulator to be sure its not stuck open.