Joe '87 S4

Lately my gas gauge needle moves/twitches for no reason. I have about 3/4 of a tank and while sitting at a stop light today it just moves slightly up and down quickly. Bad connection? Any thoughts as to the cause?

blown 87

was your turn signal on?

Joe '87 S4

No.

blown 87

Mine has done that due to voltage varyations, maybe something going on with your alternator?
Check all your grounds and the connector in the spare tire well.

ceedee

mine does a few twitch things when the turn signal is on... what does that mean?

blown 87

I have not looked at the wiring diagrams, but I am willing to bet that the fuel gauge has a reference voltage (5 volts?) to it and when the electrical system see a quick load like that you can see it on the gauge.

I bet if you put a DVOM on the reference at the tank sender you would see a flucuation on it.

Joe '87 S4

Wouldn't all the gauges show a similar response if there was an overall quick load? The gas gauge just started bouncing around one day. It's the only one that does that.

Kevin Michael

my oil pressure gauge does it too.

ceedee

mine doesn't do that with the oil gauge
but i get a strong suspition here
did you gyus ever try to clean the contacts behind the pod?
and check the 'forward' connector to the frame? (wherever it is, i couldn't find it)

killingmoon65

My 78 has done the same thing for years. Whenever the needle moves, it jumps- never a smooth, gradual movement. Charging system is strong. No other gauge issues unless all accesories are on. Water temp sometimes does it too.

blown 87

I do not know, my fuel gauge is the only one that does that also.
I have cleaned all of the grounds that I have been to so far, and it will be a few weeks before I get into the pod.

blown 87

My water temp did that for a while too, but after cleaning some of the grounds and connectors it does not do this any more, what did I do to make this right, damned if i know.

ceedee

where is the main connect under the instrument panel?

blown 87

I am not sure there is one, other than the connection for the printed circiut.
I have not ventured that far yet, but soon.

jpitman2

Get a larhe baking dish half full of water. carry it from the sink to the cooker top as fast as you can without losing much. See how long it takes for the water to come to rest. Now factor in a sliding contact moved by a float making contact with a resistor that has ben subject to fuel vapour for 20 years with deposits all over it.....Doesnt take much to produce flickers on the gauge. If there comes a point at which it wont read at all, there is a place on the resistor wire completely insulated from contact - removed pick unit and carefully clean the crud off.
jp 83 Euro S AT 50k, BTDT