Gas Gauge issue

[crazyjmk]

Hello all,

Trying to help a buddy out and save some cash. Also am I really hoping that I don't have to drop the tank...I really hate that.

The gas gauge on his van shows empty most of the time,(even when mostly full) will show full once filled, but only for a brief time, then back to empty. Trying to figure out if the sensor in gas tank is bad and/or gas gauge broken.

1996 Dodge Ram 1500 Wagon

5.2L Magnum V8

Thanks in advance!

J

[zamboni]

Sounds like a bad sending unit on the fuel pump. Mine was out on my 97 Mazda MPV when I bought it, thankfully it is one of the few vehicles on the road that has an access panel in the floor, lift the flap on the carpet, open the panel and you're looking right at it. Sorry, not sure about his Dodge, but was told there aren't many vehicles like mine on the road with that panel, so I hate to say it- but you'll probably have to drop the tank. Have him buy a Chiltons or Haynes manual, they are life savers.

[Jeremy airjer W]

I just had a Dakota in tonight with the exact same problem except the bigger problem was the connector at the pump had burnt up disabling the vehicle. The gauge always read about 1/4 tank.

More than likely it is the sending unit in the tank as this one was. the easiest way for a do it yourselfer (I use this method at the shop as well) to test is to pick up some resistors at the local radio shack (very cheap). 50, 150 and 200 ohms should be sufficient to check the operation of the gauge. place the resistors in series (one end of the resistor in the positive wire to the sending unit and the other end into the negative) then turn the key on and see what the gauge reads. You may have to watch it for a while because they gauge may not read real time (usually have some sort of delay to compensate for fuel slosh). If the gauge reads differently with each resistor you can be fairly certain that the sending unit is the problem. If the gauge does not change then you have other issues.

I can't remember what the wire colors are for the sending unit but I will get them for you tomorrow for sure.

[Shack]

What Air just said, also (now this is a cheap shot in the dark), but sulfur deposits can form on the module and sending unit in the tank. This can lead to inaccurate reads and sporadic reading of the gas gauge.

What a T.S.B. threw Ford siad to purchase a can of Techron (made by Chevron) and pour it in your tank at the next fill up. You can get it at Napa and most auto parts stores.

This T.S.B came out at first for diesel models, but I have seen it work on Taurus and Escapes. I also think Chrysler was jumping on the band wagon about a year ago.

It is a cheap/easy first step in diag. an erratic fuel gauge issue. Plus the stuff cleans other things. It would not hurt to try it.

After this, start with what Airjer just posted.

Good luck..

[Jeremy airjer W]

dark green with black - power to the pump

black - pump ground

black with white - sensor ground

dark blue - fuel signal

black with light blue - sensor return

light blue with black - low fuel out

I would start with the resistor between the dark blue and black with light blue and see what happens.

[crazyjmk]

Thanks for the quick replies! I will keep you posted on the results. We will get to it this weekend if the rain does not mess it up.

Thanks again

J