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Chevy S10 - GMC S15 and Sonoma Fuel Pump and Fuel System



  • Your problem #2 with the ABS light going off and on could be an intermentant connection in the wiring or connector. I have had problems with mine in the wheel sensor connector. Your brakes will still work normally, but with the light on the ABS should not come on during severe braking, if your wheels lock up.
  • gilnh20gilnh20 Posts: 1
    I HAVE A 1999 S-10
  • fearwvufearwvu Posts: 2
    I have a 2001 s-10 blazer 4.3 L and it was running fine until the fuel pump started whining one day allday when it was really hot out. It sat for a week and then the fuel pump would not come on or start. I had the fuel pump and filter replaced and now it will hardly run, hardly start, rough idle, bad fumes, black smoke out exhaust, stauling out, highway runs fine till I give it lots of gas. I took the EGR valve off and cleaned it along with the MAF sensor. I checked the fuel pressure and when I turn the key on it goes up to 72 then drops to 55. When I start it it pegs out at 100 and bounces around there. Any help would be appreciated! Thanks
  • haviehavie Posts: 1
    Okay so I ran out of gas on the way to work burnt my fuel pump out . I replaced fuel pump with a new one from Autozone along with the fuel filter and Maf sensor truck ran fine for two days and then died on the way home from work now it won't start at all I checked my fuel pressure regulator by putting a brand new one in and still wouldn't start . Any ideas on what could be the problem would be GREATLY appreciated .. By the way my fuel pump turns on so I believe it wasn't a faulty fuel pump
  • I would check the fuel pressure (Autozone has a gage on the loan a tool program) if the pressure is normal check the PCM for codes (Autozone has scan tools) and check for spark at the plugs. If the pressure is zero, turn the key on without starting and listen under the vehicle for the fuel pump to run for a few seconds and then it will shut off. If the pump does not run it could be a bad connection, blown fuse or a bad fuel pump. Why did you change the MAF sensor with the new pump? If this fails the vehicle should not quit running
  • gonogogonogo Posts: 871
    Aftermarket pumps have a poor reliability record.
  • got alot of snow, had 1/4 tank of gas, started it up to move it ,while it was idling in the drive way, it quit.
    gas gauge now does not work, and the fuel pump was not working, chsnged the fuse for the fuel pump, now it sounds like it kicks on for a few seconds, but the gas gauge still does not work, and it will not start. tryed a sniff of starting fluid, but wont even fire on that. could this possibly be just ice in the gasline?
  • woody70woody70 Posts: 2
    edited April 2011
    If your looking for sign that the fuel pump is going out, turn the key ON 3 or 4 times and then the 5th time try to start it, if it tries to start then that's a sign of the fuel pumps getting weak. Because the CPI(Central Port Injection)or SCPI(Sequential Central Port Injection) on the 4.3L V6 needs at lease 55 psi for it to open the Poppet Nozzle and Sprays Fuel in to the Intake Port!
  • woody70woody70 Posts: 2
    If your looking for signs of the fuel pump going out, turn the key on 3 or 4 times and than the 5th time try to start it,if it tries to start then that's a sign that the fuel pump is getting weak, because the CPI(Central Port Injection) or SCPI (Sequential Central Port Injection)of the 4.3L V6 needs at least 55 psi to push the spring back on the Poppet Nozzles to spray the fuel in to the Intake Port,if you need more information just call me at (304)578-1777 I'm a Qualified ASE Master Automotive Technician, and I'd be glad to help with your Problem!
  • bobby86bobby86 Posts: 1
    edited June 2011
    Where is the Fuel Safety Switch? we have replaced the fuel relay switch and fuel pump on our 2000 gmc sonoma with a vortex v6 motor but we cant find the fuel safety switch. We have ask some mechanics but they havent been able to tell us. CAN SOMEONE PLEASE HELP?
  • There is no fuel safety switch as other manufacturer use to shut down during a crash. You probably have a problem in the wiring, if you are not getting voltage to the pump and if you have voltage at the pump it maybe the ground.
  • I have a '98 Sonoma 4.3L. It had a rough idle and took a lot of cranking to start. I replaced the fuel pump which eliminated the cranking prob but not the rough idle. Eventually, weeks later, the truck stalled in the middle of traffic and never started again. I replaced the injector with the upgraded multi-port spider injection unit. The truck came back to life but the rough idle was still an issue (I did clean the EGR valve). The same day, I ended up not being able to start the truck again. This time, it sounds like the fuel pump is not activating. I made sure the fuse was good and I also made sure the fuel pump plug was tight.

    Is there any other possible cause for the issue with my new fuel pump? It literally only has a few hundred miles on it. I am planning to blow some air through the fuel lines to see if they are somehow clogged but I have no clue what else could have burned out the pump or if there might be some other issue preventing the pump from activating.
  • gonogogonogo Posts: 871
    Did you check the pump electrical connector for burning when you replaced the pump.
    I believe Delco even sends a repair connector with each pump.
    Repair connectors can be purchased at the dealer, maybe aftermarket, not sure.
  • Thanks for replying! Are you referring to the wiring harness? If so, I did change that out with the new fuel pump. If not, I'm not sure I know what you mean.
  • gonogogonogo Posts: 871
    Yes, pump harness. Another issue could be the ignition switch, the electrical part. Check ECMB fuse for power, it powers the pump on my 99.
  • My 2003 S-10 (4.3L V6) is not starting. Last time it started it ran fine, I filled the tank drove home and parked it. It sat for a couple weeks without running, and when I went to use it again it did not start. It cranks strong and I could smell gas when I was trying to start it so I decided to replace the plugs and wires. It still did not start, so I sprayed some starting fluid in the throttle body and after cranking a little bit it fired up. I drove it around for 15-20 mins. without any problems. I brought it home and parked it and went out at three different times that night and it fired right up after 1-2 cranks. The next day I tried to use it and it would not start again. Today I went out and got a new fuel filter and a pressure tester, when I turn the key on I hear the fuel pump humming for 2-3 seconds. I replaced the filter and connected up the pressure tester and with the key on engine not running I am getting 52psi on the gauge. Is this enough pressure? I am starting to think ignition module but I saw on the forum that the pressure needs to be at least 55psi so I am second guessing myself now.

    Also, when I am trying to start it and it doesn't start, when I let off the key the engine sometimes sputters and bluish smoke comes out of the TB.

    Thanks in advance,
  • My 2002 S10 4.3L would start hard at times then eventually it would not start without starting fluid. It turned out to be the fuel pump. I took the 8 bolts out that hold the bed on and jacked up the front to tilt in up like a dump truck to access the pump, instead of dropping the tank.
  • gonogogonogo Posts: 871
    Ive seen the lift the pump side, first time lift the front, clever.
  • My fuel pump was not activating. I checked all fuses, including ECMB, and all were working well. The wiring is good, the ground is good but the pump will not activate. I read something about Passlock but I am not sure if this is the issue. Any advice?
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