76 FI Bus- fuel gauge suddenly wonky

[Velokid1]

My fuel gauge has always been slow, and it seemed to go down from Full to 1/2 very quickly, then more slowly from 1/2 to Empty. So I never fully trusted it.

But I had a backfire, blew off a vac hose, couldn't get the bus started, so it sat for 2 weeks.

Finally got her running, gauge was on E, so I took it to the station. Pump shut off at $5. Hmm... that's weird. So I get in the bus, start her up and the needle on the fuel gauge goes from E to about 1/16th of a tank, then stops.

I'm thinking to mahself, either the gauge is wrong or the pump at the station just turned off too soon. So I goes back and tries again the next day. Pump shuts off after 1 gallon.

Start the bus... same thing. Dead E, then after a minute it's up to about 1/16th of a tank. I obviously have a full tank of gas.

Someone was invited over by my wife while I was out of town last week to "fix" my bus. He was chasing fuel delivery issues and replaced a couple short lengths of fuel line on the fuel rail (?thinkyoucallit?). Could he have also buggered around with something under the bus @the fuel tank that might have caused this new gauge malfunction?

EDIT: I also know my wife (at the direction of this intruder who was invited to molest my bus while I was away...) replaced some fuse(s) under the dash. Another clue, perhaps?

[dtrumbo]

I'm pretty sure your problem is electrical rather than mechanical and since the gauge was inaccurate prior to the alternate mechanic's visit, you can probably cut him some slack. If I were to bet, the vibrator has come loose on the back of your speedometer. Here's a thousand words worth. A picture stolen from TS. The IMG code still doesn't work so you'll have to click on the link.

http://images.thesamba.com/vw/gallery/pix/618674.jpg

See the black and brown thing with the red and black wires coming off of it? That's the vibrator. Notice on the left side there is a fork-shaped piece of metal under a nut on the back of the speedometer. This little bit of metal holds the vibrator in place, but it must, must, must be clean and snug to provide the ground connection for the vibrator to do it's thing (no, it doesn't really vibrate). If this physical connection is loose, wonky is all your fuel gauge will ever be.

Check that first and if things are still wonky-like, come back and we'll take another swing.

[dingo]

break out your multimeter...set to Ohms and take some readings...very simple

http://www.type2.com/library/misc/vwggauge.htm