93 jimmy, 4.3 Vortec - everything used to run fine, but when i got in my car one day and tried to start it up, there was no sound from the fuel pump. i didnt check the fuses and relays because i have no clue were they are located!!! there isnt a fuel pump fuse by the pedals and i cant find the fuse box under the hood!! somebody help me please!!!

 

you wont have a fuse box under the hood.
relay is either on the firewall or on the drivers fender.
there is also a red wire all by its lonesome over the brake booster on the drivers side. that is a hot wire that runs to the fuel pump. run a wire off the battery to it and see if that makes your fuel pump run.

 

the guy that towed my truck said that my fuel pump died. he said he could hear the relay when i turned the key, then he said that the pump will sound real loud before it goes and the gas guage needle will not stay still (bob up and down when driving). that is exactly what my fuel pump was doing. please tell me if that sounds correct. now i just need to know where to find a cheap pump and how to install it

 

DON'T buy a cheap pump..you get what you pay for and this is one item you don't want to scrimp on. Read thru some of the other posts and you'd be surprized at how many people have changed their pump 3-4 times in a space of a year because they bought cheap ones that didn't last. To change the pump you need to empty and then remove your gas tank, the pump, sending unit and pickup screen are all mounted in one unit on the top of the tank. Be careful when you remove it that you don't bend anything or your fuel gauge will be screwed up. Also make sure that you change the screen at the bottom of the pump..this is a strainer that prevents any chunks in your gas tank from pumping thru the system. New pumps don't come with a screen, you have to ask for it when you buy the pump.

 

i just changed my fuel pump and i still dont hear the fuel pump when i turn the key to power. do i have to reset something? could it be my etire sending unit? also, are there suppose to be three wires that come off the sending unit, or just two?

 

The truck still isn't starting right? Check your relay. It is on the firewall closest to the fender. You can easily "hot wire" this with a small fuseable link to the battery and by-pass the relay to see if the fuel pump will fire-up. Did you check the fuel pump before you installed it? This all will tell you if the relay is bad, fuelpump is bad or if you have some kind of wacky wiring problem to chase down. Make sure you have a pressure gauge as well. Did you change the fuel filter. If your filter is clogged you may be stalling the pump (fuel pressure will help you determine this as well). You have to have full pressure for the CPI to work. I had like 51# and it would not start 1/2 the time.

Also I totally agree buy the best you can find. I had a Autozone house brand in that only lasted 30,000 miles. I bought Bosch this time like I should have the first time!

 

Had the same problem with mine, turned out that the internal connector on the sending unit was fried. Made me feel real safe, with a burnt wire INSIDE the gas tank. What the hell were they thinking??

 

first of all, thank you everyone for helping me with this. now, i didnt do anything with the relay, but i can hear it clicking when i turn the key. next, ididn't change the fuel filter. if i took the old fuel pump out and put a new one in, shouldn't it need to build the pressure back up if my fuel filter was clogged? and last, how do i fix the internal wiring if mine is fried?

 

You can change the fuel filter, but, if the pump does not run, it won't help.... If the sending unit is bad, have to replace it. Yep, drop the tank again.... Such fun. Grab yourself a test lite, go to the back of your truck, reach up on top of the tank (between the bumper, and frame, about the middle of the truck) and find and disconnect the connector for the fuel pump/gas guage, and have someone cycle the key for you, and see if the test lite lites up. If it does, you need to drop the tank again. If not, your problem is further upstream.

 

i had already replaced the sending unit, the problem is that i'm getting power to the wires and the sending unit works fine, but when i connect it, nothing happens. i think there could be a bad ground somewhere, or the connector at the tank is just not connecting right