metalfanmartin Posted January 30, 2017 Share Posted January 30, 2017 (edited) G'day, 1990 L-Series wagon. My fuel gauge is all over the place. Never goes to full, and goes all over the place. Doing some research I see that I need to check the sender unit wires. I'm not sure exactly how to do that. I've located what I assume to be the unit in the boot of my car. Please see picture attached. I tried pulling this plug looking item but it doesn't budge much, I wasn't game to try too hard so I've now come to ask you guys. What's my next step? Do I need to undo all the bolts? Cheers, Martin Edited January 30, 2017 by metalfanmartin Quote Link to comment Share on other sites More sharing options...
rdweninger Posted January 30, 2017 Share Posted January 30, 2017 yes, undo the bolts and pull out the sending unit. Unplug the wire first. It will be somewhat 'glued' in with a black sticky gasket goop, which is obviously gas-proof. You will see a potentiometer, where the float 'grounds' the wire. I had to slightly bend the part where it makes contact with the coiled wires ... that was 6 years ago, and my gauge still works today. Quote Link to comment Share on other sites More sharing options...
metalfanmartin Posted January 31, 2017 Author Share Posted January 31, 2017 Thanks rdweninger. I've pulled the plug off and investigated, it looks like the earthing wire had snapped off but I'm not sure if it was when I was prying off the goopy stuff. Will solder together and see how I go. Quote Link to comment Share on other sites More sharing options...
metalfanmartin Posted February 21, 2017 Author Share Posted February 21, 2017 Damn, so I resoldered the connection and it doesn't appear to have fixed the issue. What should I do? Fuel gauge is still reading randomly. I earthed the earth wire and the gauge showed full. Quote Link to comment Share on other sites More sharing options...
CaptainDub Posted February 21, 2017 Share Posted February 21, 2017 Probably not much help but I have a similar problem in my 94 Loyale. The fuel gauge goes up a little with every flash of my right turn signal so It usually looks like I have a full tank. There must be a short somewhere between the right turn signal wiring and fuel sender wires. Perhaps yours is also related to a short elsewhere in the vehicle wiring? Quote Link to comment Share on other sites More sharing options...
metalfanmartin Posted February 24, 2017 Author Share Posted February 24, 2017 Thanks for that captain dub, but unfortunately that doesn't help me much I don't think? Because when I earth the earth wire it goes to full, which gives me the impression the signal is getting to the gauge fine. Quote Link to comment Share on other sites More sharing options...
rdweninger Posted February 27, 2017 Share Posted February 27, 2017 You need to pull the sending unit out of the fuel tank. When you look at it, you will see how a potentiometer works. As the float moves up and down, it grounds out the potent-wire at different points - Thus, giving you different readings on your gauge. Make sure the float is making contact at all points on the coiled wire. Maybe have someone watch the gauge while you move the float up and down. Not saying this is your problem, but I have fixed 2 fuel gauges this way. Good luck.. hope this works. 1 Quote Link to comment Share on other sites More sharing options...
metalfanmartin Posted February 27, 2017 Author Share Posted February 27, 2017 Thanks for that mate, I will pull it out again soon. From memory when I had it out, it was an enclosed unit? It had the float on an arm and all that, but it didn't look like I could just open it up. I'll give it a shot anyway. Quote Link to comment Share on other sites More sharing options...
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