Fuel Pump or Fuel sending unit replacement (2nd gen)

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Fuel Pump or Fuel sending unit replacement (2nd gen)

Postby bigpoppax2 » Sat Nov 19, 2016 9:13 am

Replacing the Fuel Sending Unit on a 2nd Gen Rodeo

Date: 2004, Jun 10
Author: Joe Berry

Well I decided to do a write up on this and save some others some money. The stealership wanted over $500 to change this. That was partly to do with the fact they were going to change the whole fuel pump.

You can order just the sending unit from St Charles Isuzu. 1-800-727-8066 the part number is 8-25323-011-0. The cost is under 40 dollars.

This will actually get you two sending units. Evidently they changed one of the electrical connections, so they give you two with only one plug being different. So when this one goes south, I'll cut and splice the old plug into the new sending unit.

The procedure:
1) Try and run most of the gas out of the tank, this is kind of funny considering you really have no clue how much gas you have.

2) Get the truck up on a set of good jack stands. You may also want to put a jack under the driver’s side of the axle. This will keep the locating bar from pushing down on the gas tank. Take the four bolts (14mm) holding the tank up loose, leave them in.

3) Take off the filler hose, the vent hose, and the other smaller hose (no idea what it is). These three hoses will come off easiest if you can get yourself under the back of the truck. (Those with the spare tire under the truck may have to remove the spare for room to work)

4) Put a floor jack and a piece of plywood under the tank supporting the weight, then take the bolts the rest of the way out, lower the tank down about 3-4".

5) There are two bolts (12mm) on the driver’s side of the tank that hold the fuel supply and return lines to the side of the tank. Take these out and take the fuel supply and return line off of the pump. There is a clip that you will need to pinch with your fingers and your lines should come off of the fuel pump.

6) You should now have everything off of the tank and you can drop it all of the way.


7) There is a large snap ring holding the fuel pump onto the tank. Take some compressed air and blow the area around the seal off. Remove the snap ring and carefully remove the pump and float as an assembly.


Remove the old sending unit from the pump assembly. There are a couple of clips holding it to the fuel pump, be careful taking the connections loose, there are some pieces that will be reused. Here is a shot of how it's mounted to the pump housing. You can see some of the clips that hold it in place; you can also see the burned contacts.


9) Install the old float on the new sending unit, hook up your wires and reinstall everything. The fuel pump will be kind of hard to get back seated, you just need to push hard and you will be able to get the snap ring back in.

Here is a comparison of the old sending unit on top and the new sending unit on the bottom. Note the difference in the contacts. You can see the burned contacts are almost completely gone on the old unit. Not the best design in my opinion.

All in all it was pretty easy, the hardest part is just getting the tank down. (Especially since I had over a half tank of gas.)
Good judgment comes from experience, and a lot of that comes from bad judgment.

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