Fixing Faulty/fluctuating Fuel Gauge?

[Kuba]

Hi Guys,

 

Did anyone tried to fix a faulty/fluctuating fuel gauge? I've tested the sender and at full tank it gives 20 ohm, a bit high but should be close enough, same resistance on at the gauge side. I've opened the gauge and checked it one more time on the contacts inside the gauge. There the resistance fluctuates between 20 and infinite making my gauge fluctuate.

 

I'm thinking if there's a way to fix that or should I just look for replacement?

[andyk_79]

Infinite resistance would suggest a bad connection somewhere. Worth checking all the connection spots in the gauge for a loose connection

[aircobra]

easy to pull out. mine was encrusted in some petrol by product. cleaned up with some acetone

[Kuba]

Got back to this issue and I might have fixed it.

 

The issue was definitely within the gauge itself as resistance on sender unit and connections in the dash was the same, so my plan was to disassemble the gauge and resolder any connections. Checking everything again I've noticed the reason for fluctuating infinite resistance, inside the gauge, there are two metal plates wrapped in a thin wire which flexes when current goes through the wire. One on the left side moves the gauge needle and the one on the right is some sort of a switch?

 

When I applied a bit of pressure to the switch there was no fluctuation!

 

The other side of the connection on this switch is threaded so I'm guessing it's some sort of adjustment, I've tightened it a quarter of a turn and the needle stays now in one place.

 

I'm yet to test the accuracy of the gauge now, but I have a feeling it's alright. I've done about 200kms since last refill and it shows half a tank.

 

Updated: Filled the tank full and happy to report the gauge is spot on the full mark!

 

A question to the members more proficient in electrical problems, what's the switch I've adjusted responsible for?

Edited February 22, 2018 by Kuba