1998 Dodge Caravan Fuel Gauge drops in reverse

  • 6 CYL
  • 2WD
  • 150,000 MILES

Our 1998 Dodge Grand Caravan just got a new fuel pump. Prior to the new pump the vehicle would stop and have no fuel pressure at the distribution rail on engine. Also occasionally, with a full tank, the fuel gauge would drop to emtpy and right back up triggering the idiot lamp and the chime while driving. Luckily a few raps on the tank bought me a quick trip home. Now when I put the vehicle in reverse the gauge drops to empty and when back in drive the guage goes back to full. This is very repeatable. Could it be a bad ground? Are the reverse lamps on the same ground? Thanks in advance for your help.
Do you
have the same problem?
Monday, December 15th, 2008 AT 2:34 PM

1 Reply

To answer your question, NO. I'm looking at a wiring diagram of your vehicle. The fuel level sending unit(in the tank) has it's own ground and sends a signal to the body control module via the dark blue wire. The body control module, in turn, tells the guage what to do. It sounds like there may be a bad connection somewhere. When you put the van in reverse, the engine will 'rock' in one direction and when you put it in drive, it will 'rock' the opposite direction. Some movement is normal. The motor mounts allow a little movement. I'm wondering if, when you put it in reverse, the engine moves enough in the right direction to interrupt the signal, either from the tank to the BCM or from the BCM to the instrument panel. Try the 'wiggle test'. Turn the key ON and have a partner sit in the van and watch the fuel guage while you wiggle wires under the hood. Try the larger wiring looms first. Just shake them around pretty good and see if the guage acts up. If it does, you'll be able to pinpoint where the problem is. If it doesn't, start the engine and have someone put it in reverse while you watch under the hood. Look closely at what all is moving when it goes into reverse. Does it stay incorrect as long as it's in reverse or is it just momentary? Try this and repost. We'll investigate further if we need to.
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Monday, December 15th, 2008 AT 5:37 PM

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