2002 venture fuel gauge jumps all over the place regardless of how much fuel is in it it will jump from empty to full never know how much fuel you have any help thanks csmechaniccomcastnet?

Answer ?

I have had a similar problem with my 1999 Chevrolet Venture. The best answer I was able to come up with is there may be a short in the electrical system. I would have a trained technician troubleshoot the problem. There are other possibilities, but this seems to be the most common. I couldn't afford to have it done right away, so I used my trip meter to calculate my fuel level. The next time you fill up, reset the trip meter. after 200-300 miles, fill the tank again. Devide the # of miles my the # of gallons you put into the van. This will give you an idea of the miles per gallon that you are actually getting. Track this for a few tanks and you will be able to predict when it is time to put fuel in the tank until you get the problem fixed. Hope this helps.

New answer

Having same problem with my '02 Venture. Problem with mine is that the fuel level sending unit, located inside the gas tank, on the fuel pump assembly, is opening up. It’s an open-contact variable resistor hooked to a float. As the float moves, it changes the resistance measured by the PCM (Powertrain control module). The PCM reads this signal, and adjusts the fuel gauge accordingly. If you have a voltmeter, you can check the signal from the PCM thru the electrical harness located on the driver's side, underneath the van, just where your feet would set if you were in the middle row seats. There are three connectors there, one of which is for the fuel tank. With the van off, unplug the white connector with six wires. Find the Purple wire and Black/White (black with a white trace) wire and then determine the corresponding pins on the van. Hook your voltmeter to the pins on the van, and turn the ignition to "Run" (NOT "Start"). You should see 5 volts DC. If not, you have other problems. Turn the van off. If you have an ohmmeter, or are using a multi-meter, measure the resistance of the sending unit. On '98 and later Ventures, you should read 40 ohms empty, 250 full. If you read more than 250, or unlimited or OL on your meter, then it is reading "open." One thing I did was to hook up the meter and shake the van to see what the fuel did as it moved. My unit would go from 80 ohms to open, so the PCM was not getting a consistent signal, and caused the faulty readings on my gauge. I confirmed this by hooking up a 500 ohm variable resistor in place of the sending unit and turning the van to "Run". This allowed me to vary the resistance that the PCM was seeing and confirm that the sending unit is the problem. If you try this, be sure you are on the right wires, and don't drop the resistance below 40 ohms, as this low resistance may allow too much current into the PCM. In addition, you will notice a lag time between moving the resistor and gauge movement. This is okay. The PCM takes a measurement of the fuel level resistance, and then adjusts the gauge. It's not like the old way of doing it, where the sending unit goes straight to the gauge. If you try this and the gauge doesn't move where or how you want it to, your problem may be something else. If it does work, then it's definitely the sending unit. Make sure you don't have a wire problem (broken, corroded, etc.). If not, then I would suggest replacing the fuel sending unit. They are only available from GM, part number 88964333 (look around online, too, you can find a better price than the dealership). I would suggest though, for anything other than '02, check and make sure this is the right part number for you.

To replace it, you have to drop the fuel tank. I did it in my back yard, with the rear end of the van setting on two auto ramps, and the front wheels up on 4-inch concrete blocks. There are two fuel lines to disconnect, two EVAP lines and one filler hose. The fuel lines disconnect by pinching the clips on the lines and pulling apart. The EVAP lines have a ring that you have to pinch. The filler hose has a plain old hose clamp (screw type).

WARNING: When disconnecting these lines, and working with the fuel tank in general, you WILL spill gasoline. Gasoline is highly flammable and can be explosive, so BE CAREFUL. If you are prone to accidents, or are generally inattentive when working, don’t even try this. Take it to a shop. I am not responsible if you get yourself hurt!

The fuel lines and first EVAP line disconnect at the front end of the tank, just beneath the driver’s seat. The second EVAP line disconnects behind the rear driver’s wheel, along with the filler hose. Once the lines are disconnected, you can remove the three straps that hold the tank in place. I would suggest using a floor jack to hold the tank in place, if you have one. I don’t, so when I dropped the straps, I let the tank rest on my chest and held it there as I took out the straps. A bolt on the inboard side and a t-slot on the outboard side hold the straps. Remove the bolts, and take the straps out of the slots. Remember where they go. Slide the tank out from under the van. Clean off the dirt around the fuel pump assembly before you take it out. Disconnect the lines and electrical connectors. There is either a plastic or a metal retaining ring holding the pump in place. Mine is metal, and I had to tap it out of place with a brass punch, which is non-sparking. Steel on steel is not safe around gas. Sparks cause fires! Once the ring is loose, lift the pump assembly out. You’ll have to lift and angle it over, in order to clear the strainer and sending unit float arm thru the hole. Remove the old sending unit, and replace with the new one. Make sure all your electrical connections are correct before you put it back in the tank. Check twice, maybe three times. You don’t want to repeat this job.

Return the pump assembly back to the tank, making sure that the o-ring is in place (critical). Lock the retaining ring back in place and re-connect all lines and electrical connectors.

Putting the tank back in place is essentially the reversal of the removal. However, be careful not to pinch, break, or lose your fuel or EVAP lines. Reconnect everything and start the van. It will take a couple of tries to start it. Remember, there’s no fuel in the lines yet. Once it’s running, get out, and check for leaks. If you find one, kill the engine and fix the leak.

Once I had my sending unit out of the van, I was able to see exactly what was wrong. There are two wipers on the unit, which move across a variable resistor. Each wiper is supposed to have three fingers. One of my wipers only had half of a finger, and the other had two left.

Hope this helps, and BE CAREFUL with the gas…