Howdy, Stranger!

It looks like you're new here. If you want to get involved, click one of these buttons!

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: 879
    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: 879
    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: 879
    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: 879
    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?
  • Could be the fuel pump relay under the hood in the fuse/relay center box. You can switch the fp relay with one of the others with the same part number to see if this helps.
  • Did you drop the tank or take the bed off to put in the new pump? It is easy to overlook the issue of having a bad ground but if you removed the bed, you will have had to disconnect the black ground wire from the rear of the bed. Make sure that is reattached and you may get your fuel pump to activate/turn on.
  • I took the 8 bolts out that hold the bed on and lifted the front part of the bed up like a dump truck and then you can access the top of the fuel tank to remove the pump. You do not have to disconnect the wires on the rear of the bed.
  • Will not get power to the pump. Truck sat for years went to start it the gauge quit working and i found out the pump pickup tube and pump where no good. Replaced them all. Still will not get power to the pump. I ran a jump wire to the positive on the fuel pump harness. Still will not activate the fuel pump. I test the pump out of the truck with a hot and ground. It works just fine. I checked the wires to the fuse box still no power, but the ignition all the wires where hot but the one that ingauges the starter, which later gets hot when cranking over the truck. Any ideas? possibly email me at zack 092091 @
  • If you jumped a hot 12vdc wire to the fuel pump connector on the truck did you also ground the the pump?
    The power to the fuse box goes through a fuel pump relay, which should energize for a few seconds when you key on. I assumed you checked the fuel pump fuse also? If the fuse is good could be the fuel pump relay or I have seen wires chewed in two by mice or chipmunks after setting for a while.
  • wny716wny716 Posts: 3
    i had my fuel pump replaced and found they did'nt reconnect the ground. It still worked fine,so that should'nt effect it.
  • wny716wny716 Posts: 3
    Will a newer zr5 tank fit in an 01 s10 crew cab? They no longer stock them for this model. Reg cab/ext cab tanks are different.
  • willo77willo77 Posts: 2
    did ya ever find out what was wrong? i'm haviong the same problem right now
  • willo77willo77 Posts: 2
    i have a 1999 sonoma 4x4 with 4.3 ltr vortec it was running fine and i shut it off for a minute and wouldn't start and had no fuel pressure and pump wasn't working i bought a new one ...2 days later ..same issue ..shut it off and hr later won't start and no pressure fuel pump is covered by warranty but i don't think it's a pump issue anymore ....anyone have any suggestions ...i have noticed this is a commom problem with these trucks so someone must have figured it out by now as i'm stumped ...fuses and relays are good wires aren't pinched and grounds good so whats left? and abviously no pressure but something causes it to shut off ...another relay?
Sign In or Register to comment.