Fuel pump problems 2003 s10 chev 4.3 v6

Not only check the fuse, check the fuse circuit for voltage, hot all the time, use a test light. You can unplug the fuel pump relay and use a jumper wire between terminals 30 and 87, hopefully the pump will run. If does, problem is on control side of relay, needs voltage and ground, the control side is the symbol that looks like a coil. The load side of relay is that line with arrow-head.
Also, note the inertia switch. At the moment, I can't rule out the fuel pump itself?
Any other problems, engine cranking, you have spark at the plugs and fuel injector pulse? Any applicable trouble codes?

Engine cranking, do you have spark at the plugs and fuel injector pulse? I'm trying to figure if you have more than one issue that may be connected? I don't know what testing you have done?
If you pull the fuel pump relay and use jumper between terminals 30 and 87, the fuel pump should run. If so, problem on control side of relay. The control side of relay needs voltage and ground. The ground is a constant ground, the voltage comes from pcm. The pcm may be acting properly if no voltage, depending, if there are other issues? You can see fuse for terminal 87, hot all the time.

Check voltage and ground at fuel pump, pink wire is voltage black wire is ground. The initial prime is only for key on engine off, lasts a couple seconds. You use a testlite to check voltage and ground.
Check voltage and ground for fuel pump relay. Also, you have an inertia switch, you have to check that.

For testing, you can use jumper wire at load side of fuel pump relay, the load side is that line with the arrowhead. When relay is energized that line moves to the other terminal and sends voltage to fuel pump, just unplug the relay, use jumper between terminal 30 and 87, terminal 30 is hot all the time.
The voltage and ground for the control side of relay is controlled by computer I believe, If the control side is the problem, I'd have to check wiring circuit and computer.
With engine cranking, you have injector pulse, also?

Check your main fuel relay.



Fuel Supply System


PGM-FI Main Relay


Description


This PGM-FI main relay is located behind the dashboard


lower cover. The PGM-FI main relay actually contains


two individual relays. One relay is energized whenever


the ignition is on. It supplies battery voltage to the PCM,


power to the fuel injectors, and power for the second


relay. The second relay is energized for 2 seconds when


the ignition is switched on, and when the engine is running.


It supplies power to the fuel pump.


PGM-FI


MAIN RELAY



FUEL


PUMP


RELAY


Relay Testing


NOTE: If the engine starts and continues to run, the PGMFI


main relay is OK.


1. Remove the PGM-FI main relay.


2. Attach the battery positive terminal to the No. 3*


terminal and the battery negative terminal to the


No. 2* terminal of the PGM-FI main relay. Then


check for continuity between the No. 5* terminal and


No. 2 terminal of the PGM-FI main relay.


• If there is continuity, go on to step 3.


• If there is no continuity, replace the relay and


retest.



*: 8P CONNECTOR


To FUEL PUMP


3. Attach the battery positive terminal to the No. 4 terminal


and the battery negative terminal to the No.


7* terminal of the PGM-FI main relay. Then check


that there is continuity between the No. 3 terminal


and No. 1 terminal of the PGM-FI main relay.


• If there is continuity, go on to step 4.


• If there is no continuity, replace the relay and


retest.


4. Attach the battery positive terminal to the No. 1 terminal


and battery negative terminal to the No. 2*


terminal of the PGM-FI main relay. Then check that


there is continuity between the No. 5* terminal and


No. 2 terminal of the PGM-FI main relay.


• If there is continuity, the relay is OK;


If the fuel pump still does not work, go to Harness


Testing on the next page.


• If there is no continuity, replace the relay and


retest.



To PCM CONNECTOR


TERMINAL A4


To ST. SWITCH


To GROUND


To IGN. 1 To BAT


To PCM


CONNECTOR TERMINALS


A13 and B1


FUEL PUMP


RESISTOR


FUEL PUMP

Hi, first check fuses 28 and 34 in the box under the hood. If the fuses are good, use a 12 volt test light or voltmeter to see if there is battery voltage at fuse 34. If there is voltage at the fuse, the problem is likely the fuel pump relay in the interior fuse box, but could be the ground signal/wire from the PCM. If there is no voltage at the fuse, check the socket of the PCM power relay. Pull the relay out, connect your test light clip to chassis ground, and probe the terminals in the relay socket. There should be one hot terminal with the key off and 2 hot terminals with the key on. If not, the PCM diode may be bad. Please let me know the outcome of your tests or if you have any questions, and thanks for using FixYa.

Well in a short term, you have a short circuit somewhere. Here is a detailed toturial for you. Please rate this post, thank you.

Automatic Shutdown (ASD) sense - PCM Input

The ASD sense circuit informs the PCM when the ASD relay energizes. A 12 volt signal at this input indicated to the PCM that the ASD has been activated. This input is used only to sense that the ASD relay is energized.
When energized, the ASD relay supplies battery voltage to the fuel injectors, ignition coils, and the heating element in each oxygen sensor. If the PCM does not receive 12 volts from this input after grounding the ASD reley, it sets a Diagnostic Trouble Code (DTC).

Automatic Shutdown Relay - PCM Output

The PCM operates the Automatic Shutdown (ASD) relay and fuel pump relay through one ground path. The PCM operates them by switching the ground path for the solenoid side of the realys on and off. Both realys turn on and off at the same time.
The ASD relay connects battery voltage to the fuel injectors and ignition coil. The fuel pump relay connects battery voltage to the fuel pump.
A buss bar in the power distribution center (PDC) supplies voltage to the solenoid side and contact side of the relay. The ASD relay power circuit contains a 20 amp fuse between the buss bar in the PDC and teh relay. The fuse also protects the power circuit for the fuel pump relay and pump. The fuse is located in teh PDC.
The PCM controls the relay by switching the ground path for the solenoid side of the relay on and off. The PCM turns the ground path off when the ignition switch is in the Off position. When the ignition switch is in the On or Crank position, the PCM monitors the crankshaft position sensor and the camshaft position sensor signals to determine engine speed and ignition timing (coil dwell). If the PCM does not receive the crankshaft position sensor and camshaft position when the ignition switch is in teh Run position, it will de-energize teh ASD relay.
The ASD relay and fuel pump relay are located in the PDC near the battery. The inside top of the PCD cover has a label showing relay and fuse location.

ASD and Fuel Pump Relays

The following description of operation and tests apply only to the Automatic Shutdown (ASD) and fuel pump relays. The terminals on the bottom of each relay are numbered.

'------------------'
' __85 ___________'
' __87A '87 '30 ___' Sorry for the crudeness of this. This is supposed to
' __86 ___________' be the relay terminals!
'------------------'

OPERATION
- Terminal number 30 is connected to battery voltage. For both the ASD and fuel pump relays, terminal 30 is connected to battery voltage at all times.
- The PCM grounds the coil side of the relay through terminal number 85.
- Terminal number 86 supplies voltage to the coil side of the relay.
- When the PCM de-energizes the ASD and fuel pump relays, terminal number 87A connects to terminal 30. This is the Off position. In the off position, voltage is not supplied to the rest of the circuit. Terminal 87A is the center terminal on the relay.
- When the PCM energizes the ASD and fuel pump relays, terminal 87 connects to terminal 30. This is the On position. Terminal 87 supplies voltage to the rest of the curcuit.

TESTING
The following procedure applies to the ASD and fuel pump relays.
(1) Remove relay from connector before testing.
(2) With the relay removed from the vehicle, use an ohmmeter to check the resistance between terminals 85 and 86. The resistance shoud be 75±5 ohms.
(3) Connect the ohmmeter between terminals 30 and 87A. The ohmmeter should show continuity between terminals 30 and 87A.
(4) Connect the ohmmeter between between terminals 87 and 30. The ohmmeter should not show continuity at this time.
(5) Connect one end of a jumper wire (16 guage or smaller) to relay terminal 85. Connect the other end of the jumper wire to the ground side of a 12 volt power source.
(6) Connect on end of another jumper wire (16 guage or smaller) to the power side of the 12 volt power source. Do not attach the other end of the jumper wire to the relay at this time.

WARNING: DO NOT ALLOW OHMMETER TO CONTACT TERMINALS 85 OR 86 DURING THIS TEST.

(7) Attach the other end of the jumper wire to relay terminal 86. This activates the relay. The ohmmeter should now show continuity between relay terminals 87 and 30. The ohmmeter should not show continuity between relay terminals 87A and 30.
(8) Disconnect jumper wires.
(9) Replace the relay if it did not pass the continuity and resistance tests. If the relay passed the tests, is operates properly. Check the remainder of the ASD and fuel pump curcuits.

__________________________________________________ _______________

I know you said you replaced the relay, and this is a test procedure for the relay, but I have bought bad parts in the past. The description before the test procedure at least gives you an idea of what components are wired through and controlled by the relay. One of those may be faulty. Email me if you want or need wiring diagrams and I should be able to scan them and email them to you.

I hope this helps.

Please rate this post, thank you

may be the fuel pump is the problem it may need to be replaced....hope this helps.....cheers

I'd want to check voltage and ground for fuel pump relay. The load side of relay is the line with arrowhead, when relay is energized that line with arrowhead moves to other terminal and sends voltage to fuel pump on gray wire. The control side of relay is that coil symbol, it has to have voltage and ground, the voltage comes from pcm, the ground is a chassis ground. The voltage for load side of relay is fuse protected, fp/inj fuse.

sounds like the fuel pump relay is stuck on. find the relay and replace it. hope this helps mike