Fuel Level Sensor issue fixed
Mark Fowler
05-28-2007, 04:24 PM
Just replaced a fuel level sensor and thought i'd share my experiences.
First off, my vehicle is a 1999 Chevrolet s10 with the 2.2L and 5 Speed manual.
Problem: My fuel gage would peg at full and occasionally drop down to empty or other places in between. The reason it did this is because an open circuit, or fuel level sender not making contact, will peg to full. If you unplugged the connector, you will read a full tank.
When replacing a fuel pump or just the fuel level sender, you either need to drop the tank or remove the pickup bed. I opted to remove the bed so i'd have a nice place to work and minimize the time hanging under the truck with junk falling in my face.
To remove the bed, there are 8 main bolts underneath, they are 5/8", remove those. The gas tank inlet has three small bolts that need to be unbolted, you will see these if you open the fuel lid. You will also need to remove the fuel cap. There are several light connectors near the bumper and a couple grounds that need to be unbolted. With those disconnected your bed should be loose.
I had two people help me remove the bed, but i think i could have removed it myself because i replaced it myself. The way i replaced was: stand it on the tailgate end (which i had removed to make it lighter). Placed two 4"x4" 8' long boards on the rails, well, on the ground and rails so the bed would lower onto them. Stood on the bumper and lowered the bed down, while walking back. Once the bed was on the 4"x4"s, I went behind it, lifted up and started to push it forward. Note, i had the vehicle in neutral on semi level grass. It might be a good idea to put stops in front of the wheels so it does not get away from you after the bed lays down. When the front part of the bed rested on the back tires, I went and moved the fuel intake tube under the bed. I then pushed more from the back and the vehicle rolled forward to let the bed down. Once the bed was up where it was supposed to be, I propped it up on each side individually and removed the 4"x4"s.
The fuel pump and fuel level sender are one piece. There are 3 fuel lines that just need to be squeezed properly and they come right off. There are two electrical connectors, not sure what one of them does, but the other had 4 wires which are for the fuel level sender and the fuel pump. The fuel level sender wires are orange and i forget the other color, but the fuel pump wires are gray and black. If your fuel pump is not working, you can check for 12v's on the gray and black when you turn on the key. The fuel level sender had 5volts, i think.
To remove the assembly, i used some very skinny needle nose pliers that fit in the C clip and a screwdriver to pry it out. Once the C clip was removed, just worked the assembly a bit and it came out.
The fuel level sender has a small circuit board and two copper 'brushes' that slide along and make contact on the board. The copper brushes on mine had either worn or bent back. It's possible to bend those brushes back down. I had mine working except they would lift up at the empty level and pop back to full. Instead of leaving it that way and maybe bending the float bar so that would not happen, and before i priced the fuel level sender, i start screwing around with it, pried the circuit board up and broke it. I called around, you have to get the sender from the dealer and it costs like $140. WTF? that's a rip off. Soooo, I ordered a generic GM sender from jc whitney. It goes from 0 - 90 ohms. I was able to remove the sender piece from the universal assembly and rigged it to fit in the slot the original came out of. I dont have pictures, maybe i dont want that kind of evidence, haha. Basically the ears on that piece were able to slide under the tabs for the original, with some filing off of bits, and i drilled thru the ears that held the original sender thru to the new one and screwed it on. Problem there was that it was backwards and read empty at full and vice versa. Well, that was one problem. The sender should actually start around 50ohms and go to maybe 200ohms. I ended up taking the bar with the float and put it towards the front and i soldered in a 47ohm resistor in series. The fuel level now goes from empty to maybe 5/8ths of a tank, but it moves the whole way and only cost $25. Maybe i should have spent the $140, but i bought the vehicle to resell and i'm trying not to invest too much.
Once I put it back in the tank, I was not getting any power to the fuel pump. Sigh. I went to the fuse/relay box on the drivers side under the hood. I switched the fuel pump relay with the horn relay, and the horn worked, so the relay was fine. Checked the 20 amp ECM BAT fuse and it was fine. I then checked the gray and black wires at the fuel pump and i had nothing. Realizing that the truck would not start after i disconnected the bed, i thought, maybe i disconnected something else important. I had. Near the back on the drivers side, there was a ground wire hanging loose. I reconnected that and got my 12 volts at the fuel pump. Everything then worked.
Ok, hope that helps, gotta repay the group, this forum is priceless!!
First off, my vehicle is a 1999 Chevrolet s10 with the 2.2L and 5 Speed manual.
Problem: My fuel gage would peg at full and occasionally drop down to empty or other places in between. The reason it did this is because an open circuit, or fuel level sender not making contact, will peg to full. If you unplugged the connector, you will read a full tank.
When replacing a fuel pump or just the fuel level sender, you either need to drop the tank or remove the pickup bed. I opted to remove the bed so i'd have a nice place to work and minimize the time hanging under the truck with junk falling in my face.
To remove the bed, there are 8 main bolts underneath, they are 5/8", remove those. The gas tank inlet has three small bolts that need to be unbolted, you will see these if you open the fuel lid. You will also need to remove the fuel cap. There are several light connectors near the bumper and a couple grounds that need to be unbolted. With those disconnected your bed should be loose.
I had two people help me remove the bed, but i think i could have removed it myself because i replaced it myself. The way i replaced was: stand it on the tailgate end (which i had removed to make it lighter). Placed two 4"x4" 8' long boards on the rails, well, on the ground and rails so the bed would lower onto them. Stood on the bumper and lowered the bed down, while walking back. Once the bed was on the 4"x4"s, I went behind it, lifted up and started to push it forward. Note, i had the vehicle in neutral on semi level grass. It might be a good idea to put stops in front of the wheels so it does not get away from you after the bed lays down. When the front part of the bed rested on the back tires, I went and moved the fuel intake tube under the bed. I then pushed more from the back and the vehicle rolled forward to let the bed down. Once the bed was up where it was supposed to be, I propped it up on each side individually and removed the 4"x4"s.
The fuel pump and fuel level sender are one piece. There are 3 fuel lines that just need to be squeezed properly and they come right off. There are two electrical connectors, not sure what one of them does, but the other had 4 wires which are for the fuel level sender and the fuel pump. The fuel level sender wires are orange and i forget the other color, but the fuel pump wires are gray and black. If your fuel pump is not working, you can check for 12v's on the gray and black when you turn on the key. The fuel level sender had 5volts, i think.
To remove the assembly, i used some very skinny needle nose pliers that fit in the C clip and a screwdriver to pry it out. Once the C clip was removed, just worked the assembly a bit and it came out.
The fuel level sender has a small circuit board and two copper 'brushes' that slide along and make contact on the board. The copper brushes on mine had either worn or bent back. It's possible to bend those brushes back down. I had mine working except they would lift up at the empty level and pop back to full. Instead of leaving it that way and maybe bending the float bar so that would not happen, and before i priced the fuel level sender, i start screwing around with it, pried the circuit board up and broke it. I called around, you have to get the sender from the dealer and it costs like $140. WTF? that's a rip off. Soooo, I ordered a generic GM sender from jc whitney. It goes from 0 - 90 ohms. I was able to remove the sender piece from the universal assembly and rigged it to fit in the slot the original came out of. I dont have pictures, maybe i dont want that kind of evidence, haha. Basically the ears on that piece were able to slide under the tabs for the original, with some filing off of bits, and i drilled thru the ears that held the original sender thru to the new one and screwed it on. Problem there was that it was backwards and read empty at full and vice versa. Well, that was one problem. The sender should actually start around 50ohms and go to maybe 200ohms. I ended up taking the bar with the float and put it towards the front and i soldered in a 47ohm resistor in series. The fuel level now goes from empty to maybe 5/8ths of a tank, but it moves the whole way and only cost $25. Maybe i should have spent the $140, but i bought the vehicle to resell and i'm trying not to invest too much.
Once I put it back in the tank, I was not getting any power to the fuel pump. Sigh. I went to the fuse/relay box on the drivers side under the hood. I switched the fuel pump relay with the horn relay, and the horn worked, so the relay was fine. Checked the 20 amp ECM BAT fuse and it was fine. I then checked the gray and black wires at the fuel pump and i had nothing. Realizing that the truck would not start after i disconnected the bed, i thought, maybe i disconnected something else important. I had. Near the back on the drivers side, there was a ground wire hanging loose. I reconnected that and got my 12 volts at the fuel pump. Everything then worked.
Ok, hope that helps, gotta repay the group, this forum is priceless!!
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