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Chevy Silverado and GMC Sierra Fuel Pump/Fuel System



  • Christina, I sent you a couple responses thru E-mail, the problem is the injector pump. The truck won't be finished by today at all........
  • Now the dealership says that the crank is broke. They replaced the injector pump and the truck didn't start. The problem we have is that if the crank was broken the motor would have a lot of different noises to it when it was turning over and when we were on the side of the road there were no other different noises. I believe the dealer doesn't know what the hell they are doing (in my opinion)..... It would be nice if someone from GM would call me on this matter............

  • I have a 1998 Silverado with a 5.7 liter engine. I recently did a full tune-up on it to include spark plugs, ignition wires, distributor cap and rotor.The problem is the truck runs fine until it warms up,then the truck is hard to start and you have to hold the accelerator to the floor before it starts and sometimes it runs rough like it's running rich. It's not showing any trouble codes on my scan tool. I did a resistance check on the temp sensor and it's within tolerance according to my service manual and there is the correct voltage going to the temp sensor. Have changed the knock sensor too. I haven't been able to diagnose what is causing this. Any helpwould be greatly appreciated and thanks in advance
  • Did you get the plug wires on snug?

    and have you checked the mass air flow sensor? It should be on the 3-4" tube that connects from the air box to the intake(?) and look like a plastic credit card holder sticking off the side. Do a 'tap' test when you start it from cold and see if it cuts out. This killed me in diagnostic time on a couple GMs the first time I encountered a bad one. They have a tendancy to cut out only when hot. If you were inthe air filter box you could have flexed, cracked, unplugged the sensor.
  • I did check all the wires and connections. I tried a different mass air flow sensor that I knew was good and it still did the same thing. The air box and sensor are all good . It runs fine until it warms up,then acts up. I'm thinking it could be a leaking fuel pressure regulator
  • I have a 2008 gmc sierra last 8 vin 8Z160870 4WD pickup was running when parked would not start in morning did some test was not getting fuel assumed fuel pump 115,000 miles,replaced fuel pump and still would not start. applied power to pump and pickup started removed power and truck died. have no power at 20amp pump fuse, key on or off, pump relay has power but jumping relay dosent work any ideas
  • Hey i have the same car and i checked and replaced the feul filter and fuel pump now im geting good pressure and good volume but the fuel injectors wont fire there are two fuel injectors. But evry now and then when i turn it over for a long long time and once and a blue moon it will start and when it deos start it runs fine then it will start up for the rest of the day then when u let it set for a few days its a pain in the [non-permissible content removed] to start again
  • I am having problems with my fuel pump I think. My truck one day just would not start, it would just sit and crank but would not turn over. Me, my dad and my brother dropped the tank and replaced the pump. In the process my old man ripped one of the wire on the female 4 pin connector. So I got a new one but the color of the wires on the new plug are different from the stock connecter. I just put them on so the colors match. And my truck will still not start. I have looked at IGN 1 relay and it was backwards for some reason so i put it on right and all the fuses look good in my fuse box. Please help me.
  • I can't remember on if it is the same on the older ones, but on 99 and newer, it sounds like the fuel regulator. It is up on the fuel rail.
  • byron06, have you figured out your problem yet? I have a 03 1500 hd 4X4 and also changed out my pump after checking all the fuses and relays and only have 5 volts at pump, i also ran 12 volt lead to pump and the truck will start and run but only with the jumper. I seem to have 12 volts leaving the fuse box from relay and fuse but it is not getting to the pump, i also checked if the circuit ran to oil pressure swtich and i had 5 volts there as well, any ideas on where to check?
  • cologuy
    I may have the same problem as you have, i also installed a new pump and can only make it work with a 12 volt jumper, looks like i only have 5 volts at pump but i do have 12 volts leaving the fuse pump, did you come up with anything?
    Thanks in advance
  • cologuy
    I may have the same problem as you have, i also installed a new pump and can only make it work with a 12 volt jumper, looks like i only have 5 volts at pump but i do have 12 volts leaving the fuse box, did you come up with anything?
    Thanks in advance
  • I have the same issue, did u happen to find the problem? Thanks in advance.
  • I have the same issue. Have you found the problem?
  • Yes! I did find the problem, it was the red connector that is under the fuse box (I think there are four large square connectors). That red square connector sends power to several things, but the very corner pin feeds the gray wire to the fuel pump. The blade (male part) of the fuse box was not making good contact with the female part of the connector, i do not know how that happened because the truck had always been running before with no problems and that connector is held on with a screw in the middle.
    I was almost ready to change the contol module because that is what controls the fuel pump but i did have 12 volts at the 20 amp fuse that was not getting to the pump.
  • onvolonvol Posts: 2
    I Have a 1999 GMC Sierra. I replaced the fuel pump about 8 months ago. My cousin is a master mechanic and he helped me wire it up, the fuel pump I got from O'reilly Auto Parts was a universal style for a few different years of the sierra. On my model I had to reverse the power wires and rewire it with the supplied plug. (came with multiple plugs as different years have different plugs. If this helps, your welcome :-) I wouldn't of figured it out on my own as always before red goes with red black with black... not red /black , black/red...
  • Same issue only I have the 5.3. Did you find a soloution to this issue? had all plugs, wires, fuel pump replaced 2 months ago. any suggestions?
  • srg67srg67 Posts: 1
    I am having the same problem i replaced the fuel pump it will start but just for a few seconds then dies. Can you hear your fuel pump come on when you turn the key on?
  • dan265dan265 Posts: 1
    sounds like I have the same problem. What color wire did you jump at the pump? Thanks in advance
  • onvolonvol Posts: 2
    The way I had to do my wiring on a new fuel pump as per a master mechanic cousin of mine: 1. Hook up black and white on pump side to black wire on truck side.
    2. Hook up all matching colors left.
    3. There are 2 wires left that do not match, hook those up.

    This was used for a 1999 sierra 4.8 with replacement fuel pump from O'reilly's Auto Parts.
    If this helps, feel free to say it worked for you! I hope this solves alot of your problems. :)
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