[dougnewport01]

Hello All! I have a strange scenario with my fuel gauge. When the tank is full and after a cold start, it flutters / vibrates with a slight buzzing noise (video below). After a minute or two is stops. Also, as the tank level goes down, this behavior subsides. At around 1/2 tank and lower it stops. If you look closely, it still has a slight vibration, but difficult to see.

I was going to find another gauge to eliminate that as the issue, but was hoping someone here might have a thought. My gut tells me it's not the gauge, rather a wonky signal from the sender, perhaps a ground issue?

Any direction would be appreciated!

Regards,
Doug

 

[Jim Walters]

Doug, if you ground the sender wire for a second and the fuel gauge needle goes full without vibrating that should eliminate the gauge as faulty. If it still vibrates that would indicate a faulty gauge. The instrument test box for later SZ's has a fuel gauge calibration mode, I wonder if the Arnage has the same requirement. I'll check the Bentley Omitec diagnostic info to see if there is anything on that for the Arnage.

 

[dougnewport01]

Hi Jim,

I ruled out he gauge (swapped in a known good one). Any thougths on the output? Its almost like interference from something or I suppose odd activity from the sending unit itself.

 

[mikebentleyturbo2]

Don't know arnages but maybe faulty voltage stabiliser?

 

[vintik]

You need to connect a Digital Oscilloscope to pins 1, 2, 3. To find out where the AC voltage comes from.

If there is AC voltage on pin 1, then the problem is probably in the instrument panel.
If pin 2, then the diode is probably defective in the alternator.
If pin 3, you need to check the ground.
The Digital Oscilloscope may be the simplest.

 

[dougnewport01]

Thank you for this, I'll check it out and share my results.

 

[mikebentleyturbo2]

Hi vintic, I built and use one of those scopes , found my faulty knock sensors with it , great eh?
I agree with you , must AC must be coming from the dip the others are( should be) DC.
Mike

 

[vintik]

Right you are! Repairing a modern car without an oscilloscope is very difficult.

 

[dougnewport01]

Here's what I found when grounding each with my multimeter:

Pin 1 (Y) 1.3V showing
Pin 2 (G) .015V
Pin 3 (B) NONE

What are your thoughts...forgive my ignorance as my electrical knowledge is nil!

 

[vintik]

So it will not work. Need a qualified assistant.