1999 Chevy Suburban 1999 Suburban won't start, electrical /

Tiny
ALB
  • MEMBER
  • 1999 CHEVROLET SUBURBAN
  • V8
  • 4WD
  • AUTOMATIC
  • 180,000 MILES
I have a 1999 Suburban, 5.7L V8, 4WD that will not start. A little background: last year the Suburban would not start one day. I noticed I could not hear the normally noisy fuel pump when the ignition was on. Checked fuses, fuel pump relay, seemed OK. Had it towed and they replaced the fuel pump. Worked fine for a month, then just would not start again one day. Seemed like the same problem. After fuel pressure test showed only 40psi, fuel pump replaced again, with GM unit. Then a couple days later, it just died while driving. Replacing the fuel pump relay took care of it (although it seemed odd at the time). It's been fine for a year.

Today it would not start, and again when then ignition is on I don't hear the fuel pump, which I believe I should. Bench tested two different fuel pump relays (have a spare) and both are fine, I can hear and feel them actuate. I expected to hear/feel a click when plugging the relay into the socket (with the ignition on) but nothing happens. Checked the voltage for the relay coil at the socket vs. Gnd, 12.9V. Left the voltmeter on the relay coil pin, then connected the relay (using a piece of wire) and the voltage dropped off to almost nothing. The other relay coil wire was connected to chassis gnd. (I did not check the + coil voltage vs. The other coil pin with the relay connected, only referenced to gnd). I have wiring diagrams from a Hayes manual ("typical 1996 and up") which show a fuel pump relay, as well as fuel pump balance relay. This is confusing me a bit.

Also, there is only one wiring connector that I can see which goes up to the area above the fuel tank/pump area. It's a 2-wire connector. I do not get any voltage vs. Gnd on either of the wires. I assumed 1 of these wires is for the level sensor and the other for the pump motor, but I am not sure. I don't know if I'm on the right track, or what to look at next. Help is appreciated!
Do you
have the same problem?
Yes
No
Tuesday, November 24th, 2009 AT 11:56 PM

1 Reply

Tiny
MERLIN2021
  • EXPERT
NO START-ENGINE CRANKS OKAY (4.3L, 5.0L, 5.7L & 7.4L) General Inspection 1. Ensure proper starting procedure is being used. Visually check vacuum hoses for splits, kinks and proper connections, as shown on Vehicle Emission Control Information label. Check ignition wires for cracking, hardness and proper connections at both coil pack and spark plugs. 2. Remove spark plugs. Check and replace as necessary. In very cold temperatures, ensure oil is proper viscosity and not contaminated with gasoline. Ignition System 1. Perform On-Board Diagnostic (OBD) system check. See ON-BOARD DIAGNOSTIC (OBD) SYSTEM CHECK in appropriate SELF-DIAGNOSTICS article. After performing OBD system check, go to next step. 2. Attempt to start engine. If engine starts and continues to run, see appropriate TROUBLE SHOOTING - NO CODES article. If engine does not start, go to next step. 3. For "P" series, go to next step. On all models except "P" series, install scan tool. Monitor VTD FUEL DISABLED parameter while cranking engine. If VTD FUEL DISABLED parameter is active while cranking engine, diagnose anti-theft system. See appropriate ANTI-THEFT SYSTEMS article in ACCESSORIES & EQUIPMENT. If VTD FUEL DISABLED parameter is not active while cranking engine, go to next step. 4. Using scan tool, monitor Throttle Position (TP) sensor voltage with throttle closed. If TP sensor voltage is greater than 2.5 volts, go to DTC P0121. See appropriate SELF- DIAGNOSTICS article. If TP sensor voltage is 2.5 volts or less, go to next step. 5. Using scan tool, monitor Engine Coolant Temperature (ECT) sensor. If ECT sensor value is less than -22 F (-30 C), go to DTC P0118. See appropriate SELF-DIAGNOSTICS article. If ECT sensor value is -22 F (-30 C) or greater, go to next step. 6. Using Spark Tester (J-26792), check for spark at 2 spark plug wires while cranking engine. If spark is present at both wires, go to next step. If spark is not present at both wires, diagnose components and power, ground and signal circuits related to ignition system. See appropriate wiring diagram in WIRING DIAGRAMS article. Also see BASIC IGNITION SYSTEM CHECKS. Repair as necessary. 7. Turn ignition off. Reconnect spark plug wires. Connect fuel pressure gauge. Turn ignition on with engine off. Observe fuel pressure. If fuel pressure is 55-60 psi (3.9-4.3 kg/cm 2 ), go to next step. If fuel pressure is not as specified, diagnose fuel system. See BASIC FUEL SYSTEM CHECKS (GASOLINE ENGINES). 8. Turn ignition off. Disconnect fuel injector harness connector at intake manifold. Using a test NOTE: Before performing the following tests, check battery condition, engine cranking speed and for adequate fuel in tank. NOTE: VCM data is deleted when using scan tool CLEAR INFO function. Before clearing DTCs, use scan tool CAPTURE INFO function to record FREEZE FRAME and FAILURE RECORDS data. Light connected to ground, probe each fuel injector feed circuit while cranking engine. See appropriate wiring diagram in WIRING DIAGRAMS article. If test light illuminates for each circuit, perform fuel injector coil test. See FUEL SYSTEM (GASOLINE) in appropriate SYSTEM & COMPONENT TESTING article. Also, check for any engine mechanical problems. Repair as necessary. If test light does not illuminate, diagnose fuel injector circuit. See FUEL SYSTEM (GASOLINE) in appropriate SYSTEM & COMPONENT TESTING article. Fuel System Electrical Circuit 1. Perform On-Board Diagnostic (OBD) system check. See ON-BOARD DIAGNOSTIC (OBD) SYSTEM CHECK in appropriate SELF-DIAGNOSTICS article. After performing OBD system check, go to next step. 2. Turn ignition off. If fuel pump runs continuously, go to step 26. If fuel pump does not run, go to next step. 3. Inspect ECM B fuse (20-amp), located in underhood fuse/relay center. If fuse is okay, go to next step. If fuse is open, go to step 21. 4. Turn ignition on. Install scan tool. Using scan tool, command fuel pump relay on. If fuel pump operates, go to IGNITION SYSTEM. If fuel pump does not operate, go to next step. 5. Remove fuel pump relay. Using a fused jumper wire, jumper fuel pump positive feed circuit to fuel pump relay ignition feed circuit at fuel pump relay connector. See appropriate wiring diagram in WIRING DIAGRAMS article. If fuel pump operates, go to next step. If fuel pump does not operate, go to step 7. 6. Using a test light connected to ground, probe fuel pump relay control circuit at fuel pump relay connector. See appropriate wiring diagram in WIRING DIAGRAMS article. Using scan tool, command fuel pump on. If test light illuminates, go to step 8. If test light does not illuminate, go to step 9. 7. Using a test light connected to ground, probe ignition feed circuit at fuel pump relay connector. See appropriate wiring diagram in WIRING DIAGRAMS article. If test light illuminates, go to step 10. If test light does not illuminate, go to step 11. 8. Using a test light connected to battery positive, probe ground circuit at fuel pump relay connector. See appropriate wiring diagram in WIRING DIAGRAMS article. If test light illuminates, go to step 12. If test light does not illuminate, go to step 13. 9. Check for an open or short to ground in fuel pump relay control circuit. Repair as necessary. After repairs, go to step 31. If circuit is okay, go to step 14. 10. Reinstall fuel pump relay. Disconnect fuel pump harness connector. Using a test light connected to ground, probe fuel pump positive feed circuit at fuel pump harness connector (body harness side). See appropriate wiring diagram in WIRING DIAGRAMS article. Using scan tool, command fuel pump on. If test light illuminates, go to step 15. If test light does not illuminate, go to step 16. 11. Repair open in fuel pump relay ignition feed circuit. After repairs, go to step 31. 12. Replace fuel pump relay. After repairs, go to step 31. 13. Repair open in fuel pump relay ground circuit. After repairs, go to step 31. 14. Check for poor connections at VCM. Repair as necessary. After repairs, go to step 31. If connections are okay, go to step 17. 15. Using a test light connected to battery positive, probe ground circuit at fuel pump harness
connector (body harness side). See appropriate wiring diagram in WIRING DIAGRAMS article. If test light illuminates, go to step 18. If test light does not illuminate, go to step 19. 16. Repair open or short to ground in fuel pump positive feed circuit. After repairs, go to step 31. 17. Replace VCM. Perform VCM relearn procedures. After repairs, go to step 31. 18. Check fuel pump positive feed and ground circuits at fuel pump harness connector for poor connections. Repair as necessary. After repairs, go to step 31. If connections are okay, go to step 20. 19. Repair open in fuel pump ground circuit. After repairs, go to step 31. 20. Replace fuel pump. After repairs, go to step 31. 21. Turn ignition off. Disconnect fuel pump harness connector. Remove fuel pump relay. Using a test light connected to battery positive, probe fuel pump positive feed circuit at fuel pump relay connector. See appropriate wiring diagram in WIRING DIAGRAMS article. If test light illuminates, go to next step. If test light does not illuminate, go to step 23. 22. Repair short to ground in fuel pump positive feed circuit. After repairs, go to step 31. 23. Using a test light connected to battery positive, probe ignition positive feed circuit at fuel pump relay connector. See appropriate wiring diagram in WIRING DIAGRAMS article. If test light illuminates, go to next step. If test light does not illuminate, go to step 25. 24. Repair short to ground in fuel pump relay ignition feed circuit. After repairs, go to step 31. 25. Check fuel pump positive feed circuit in fuel pump wiring harness (tank side) for a short to ground. Repair as necessary. After repairs, go to step 31. If circuit is okay, go to step 20. 26. Remove fuel pump relay. If fuel pump continues to run, go to step 30. If fuel pump does not run, go to next step. 27. Turn ignition off. Using a test light connected to ground, probe fuel pump relay control circuit at fuel pump relay connector. See appropriate wiring diagram in WIRING DIAGRAMS article. If test light illuminates, go to step 29. If test light does not illuminate, go to next step. 28. Replace fuel pump relay. After repairs, go to step 31. 29. Repair fuel pump relay control circuit for a short to ground. After repairs, go to step 31. 30. Repair fuel pump positive feed circuit for a short to power. After repairs, go to step 31. 31. Using scan tool, clear DTCs. Attempt to start engine. If engine starts and continues to run, go to next step. If engine does not start, go to step 4. 32. Allow engine to reach normal operating temperature. Using scan tool, check for DTCs. If any DTCs are present, diagnose DTCs. See appropriate SELF-DIAGNOSTICS article. If no DTCs are present, system is okay. Wiring Diagram emailed to ID wire colors, Fuel pump will only run for 2-3 seconds with key on, use the prime connector on left side of engine compartment.
Was this
answer
helpful?
Yes
No
Wednesday, November 25th, 2009 AT 8:47 AM

Please login or register to post a reply.

Recommended Guides