1996 Chevy Van will only run if put fuel into intake. Fuel

Tiny
BATTLINBRY
  • MEMBER
  • 1996 CHEVROLET VAN
Engine Performance problem
1996 Chevy Van V8 Two Wheel Drive Automatic

my 1996 chevy van 5.7 liter engine . There is fuel coming from the fuel pump all the way to the engine. I put a new fuel pump relay, fuel filter, and the fuel pump works pushing gas through the filter all the way to the engine. But it will only start and run if I put fuel source into the throttel body intake
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Thursday, March 11th, 2010 AT 6:17 PM

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Tiny
OBXAUTOMEDIC
  • EXPERT
Hello,

Have you tested the Injectors and wiring harness? They are located in the throttle body. A Noid light would help with testing.

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Thursday, March 11th, 2010 AT 6:53 PM
Tiny
OBXAUTOMEDIC
  • EXPERT
Here is Basic Fuel System Check

BASIC FUEL SYSTEM CHECKS FUEL SYSTEM PRESSURE RELIEF WARNING:

FUEL SYSTEM PRESSURE TEST WARNING:

Begin fuel system trouble shooting and diagnosis with fuel system pressure test. Relieve fuel system pressure before disconnecting any components or installing fuel pressure gauge.
Fuel system is under pressure, which must be relieved before servicing fuel system. Fuel pressure may be relieved by one of the following methods.

Disconnect negative battery terminal. Loosen fuel filler cap.

Install Fuel Pressure Gauge (J-34730-1A) to fuel pressure test head. Wrap shop towel around pressure connection when installing fuel pressure gauge to absorb fuel leakage. Place gauge bleed hose in container. Open bleed valve to relieve fuel pressure.

Begin fuel system trouble shooting and diagnosis with fuel system pressure test. Relieve fuel system pressure before disconnecting any components or installing fuel pressure gauge.

1. Perform ON-BOARD DIAGNOSTIC (OBD) SYSTEM CHECK. After performing OBD system check, go to next step.

2. Relieve fuel pressure. See FUEL SYSTEM PRESSURE RELIEF. Connect Fuel Pressure Gauge (J-34730-1A) to fuel pressure test port. Turn ignition on with engine off. Fuel pressure should be 60-66 psi (4.2-4.6 kg/cm 2) on CSI fuel system and 56-62 psi (4.0-4.4 kg/cm 2) on SFI fuel system, and should hold steady. If fuel pressure is as specified, go to next step. If fuel pressure is not as specified, go to step 9

3. Turn ignition off for 10 seconds and then turn ignition on. Fuel pump should run for 2 seconds. Observe fuel pressure. If pressure is within specification and holds, go to step 5. If pressure is not within specification or is within specification but does not hold, go to next step.

4. Turn ignition off for 10 seconds. Turn ignition on. Pinch off fuel pressure feed line. If pressure is as specified and holds, go to step 6. If pressure is not as specified or is as specified but does not hold, go to step 8.

5. Warm engine to normal operating temperature. From idle, open throttle quickly. Observe fuel pressure. If fuel pressure is within specification, see TESTS W/O CODES article. If fuel pressure is not within specification, go to step 23.

6. Check for partially disconnected fuel pulse dampener/pulsator. If dampener/pulsator is partially disconnected, go to next step. If dampener/pulsator is okay, go to step 13.

7. Repair connection at fuel pulse dampener/pulsator. After repairs, go to step 28.

8. Check fuel feed line between pinch and CSI/SFI unit. If fuel feed line is okay, go to step 23. If fuel feed line is restricted or leaking, go to step 27.

DO NOT allow fuel pressure to exceed 75 psi (5.3 kg/cm 2).

9. Turn ignition off for 10 seconds. Turn ignition on. Fuel pump should operate for about 2 seconds. Observe fuel pressure after fuel pump stops. If pressure is present, go to step 14. If pressure is not present or drops, go to next step.

10. Turn ignition off. Connect a fused jumper wire to battery voltage. Jumper fuel pump test terminal. If fuel pump operates, go to next step. If fuel pump does not operate, see FUEL SYSTEM test in A-3, NO-START DIAGNOSIS.

11. Check for plugged fuel filter, plugged fuel pump strainer, restricted fuel line or disconnected fuel pulse dampener/pulsator. After repairs, go to step 28.

12. Check for restricted fuel line, fuel filter, plugged fuel pump strainer or disconnected fuel pulse/pulsator. After repairs, go to step 28.

13. Replace fuel pump. After repairs, go to step 28.

14. Turn ignition off for 10 seconds and then turn ignition on. Fuel pump should operate for about 2 seconds. Observe fuel pressure. If fuel pressure is greater than 66 psi (4.6 kg/cm 2) on CSI fuel system or 62 psi (4.4 kg/cm 2) on SFI fuel system, go to next step. If fuel pressure is not greater than specified, go to step 16.

15. Relieve fuel pressure. Disconnect fuel return line. Attach a fuel hose to fuel regulator return line and place in a container. Turn ignition on. Observe fuel pressure within 2 seconds after turning on ignition. If fuel pressure is greater than 60 psi (4.2 kg/cm 2) on CSI fuel system or 56 psi (4.0 kg/cm 2) on SFI fuel system, go to step 17). If fuel pressure is less than as specified, go to step 19.

16. Turn ignition off for 10 seconds. Turn ignition on. Fuel pump should operate for about 2 seconds. Observe fuel pressure. If fuel pressure is less than 60 psi (4.2 kg/cm 2) on CSI fuel system or 56 psi (4.0 kg/cm 2) on SFI fuel system, go to step 20. If fuel pressure is greater than as specified, go to step 28.

17. Check for restricted fuel line from fuel pressure regulator to point where fuel line was disconnected. If fuel line is restricted, go to next step. If fuel line is not restricted, go to step 23.

18. Repair restriction in fuel return line from pressure regulator to the point where fuel line was disconnected. If fuel return line is restricted, go to next step. If fuel return line is not restricted, go to step 23.

19. Repair restriction in fuel return line to fuel tank. After repairs, go to step 27.

20. Check for restricted fuel line or fuel filter. After repairs, go to step 27.

21. Repair or replace restricted fuel line or fuel filter. After repairs, go to step 27.

22. Turn ignition off. Connect a fused jumper wire between battery voltage and fuel pump test terminal. Slowly pinch fuel line return hose. Fuel pressure should increase to greater than 66 psi (4.6 kg/cm 2) on CSI fuel system or 62 psi (4.4 kg/cm 2) on SFI fuel system. If fuel pressure increases to greater than as specified, go to next step. If fuel pressure is less than as specified, go to step 24.

23. Replace fuel pressure regulator. After repairs, go to step 28.

24. If fuel pressure is less than 60 psi (4.2 kg/cm 2) on CSI fuel system or 56 psi (4.0 kg/cm 2) on SFI fuel system, go to next step. If fuel pressure is greater than specified, go to step 28.

INJECTOR CIRCUIT DIAGNOSIS (A-4)

This test only applies to vehicles equipped with a VCM.

25. Check for faulty fuel pump, partially disconnected fuel pulse dampener/pulsator, partially restricted fuel pump stainer or incorrect fuel pump. Repair as necessary. After repairs, go to step 26. If problem is not found, go to step 28.

26. Repair or replace fuel pump, partially disconnected fuel pulse dampener/pulsator, partially restricted fuel pump strainer or incorrect fuel pump. After repairs, go to next step.

27. Replace fuel feed/supply line. After repairs, go to next step.

28. Using scan tool, select DTC, CLEAR INFO function. Attempt to start engine. If engine starts and continues to run, go to next step. If engine does not start or starts and stalls/dies, go to step 2.

29. Warm engine to normal operating temperature. Using DTC, select DTC, FAILED THIS IGN function. If any DTC(s) are displayed, diagnose and clear DTC(s). See TESTS W/CODES article. If DTC(s) are not present, go to next step.

30. Using scan tool, select CAPTURE INFO, REVIEW INFO function. If additional DTC(s) are stored, diagnose and clear DTC(s). See TESTS W/CODES article.

1. ON-BOARD DIAGNOSTIC (OBD) SYSTEM CHECK. After performing OBD system check, go to next step.

2. Disconnect injector connector at intake manifold. Turn ignition on. Using test light connected to ground, probe ignition feed circuits. See WIRING DIAGRAMS article. If test light illuminates, go to next step. If test light does not illuminate, go to step 7.

3. Install injector test light to each injector circuit, one at a time. Crank engine. If injector test light flashes on each injector, check fuel injector(s). See FUEL SYSTEM in SYSTEM/COMPONENT TESTS article. If injector test light did not flash on an injector circuit, go to next step.

4. If injector test light was on steady on an injector circuit, go to next step. If injector test light did not illuminate on an injector circuit, go to step 6.

5. Install injector test to affected injector. Turn ignition off. Disconnect Blue and Red VCM connectors. Turn ignition on, with engine off. If injector test light turns off, go to step 11. If injector test light stays on, go to step 8.

6. Check for open or short in battery circuit to affected injector. If circuit is open or shorted, go to next step. If circuit is okay, go to step 9.

7. Repair circuit as necessary. After repairs, go to step 12.

8. Repair short to ground in injector control circuit. After repairs, go to step 12.

9. Check terminal contact at VCM connector. If terminal contact is faulty, go to next step. If terminal contact is okay, go to step 11.

10. Repair terminal contact. After repairs, go to step 12.

11. Replace VCM. Reprogram replacement VCM. After replacing VCM, go to next step.

12. Using scan tool, select DTC, CLEAR INFO mode. Attempt to start engine. If engine starts and continues to run, go to next step. If engine does not start or starts and stalls/dies, go to step 14.

13. Warm engine to normal operating temperature. Using scan tool, select DTC, FAILED THIS IGN mode. If other DTC(s) are present, diagnose affected DTC(s). If no other DTC(s) are present, go to next step.

14. Using scan tool, select CAPTURE INFO, REVIEW INFO. If additional undiagnosed DTC(s) are present, diagnose affected DTC(s). If DTC(s) are not present, system is okay.

.
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Thursday, March 11th, 2010 AT 7:25 PM

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