Big Mark Posted December 31, 2015 Share Posted December 31, 2015 (edited) My fuel gauge is saying full for the last two days even tho it's not as have done 100's of miles. It's done it a couple of times in the past on drives but sorted itself out, but this time it won't budge from full. Would a faulty sender cause the gauge to read full or do I need to look elsewhere for the cause? edit: I should of mentioned that I'd had the battery disconnected for a couple of days. Edited February 15, 2016 by Big Mark (see edit history) Quote Link to comment Share on other sites More sharing options...
supra900bhp Posted December 31, 2015 Share Posted December 31, 2015 Maybe a sticky float in tank?? I had a old pug done it here and there more if it was parked up hill I swapped it for a second hand one was fine Quote Link to comment Share on other sites More sharing options...
JayJay1374 Posted January 1, 2016 Share Posted January 1, 2016 When I first bought my car the fuel gauge didn't work. I checked in the tank and the float had separated causing fault reading. Remove the fuel pump and have a look. Quote Link to comment Share on other sites More sharing options...
Big Mark Posted January 1, 2016 Author Share Posted January 1, 2016 Thought as much, I'll pull the fuel pump hanger out and check it all out. Quote Link to comment Share on other sites More sharing options...
fastcar Posted January 1, 2016 Share Posted January 1, 2016 Mine is always reading empty, such a pain lol Quote Link to comment Share on other sites More sharing options...
Big Mark Posted January 17, 2016 Author Share Posted January 17, 2016 I checked the float with a multi-meter and the resistance changes as the arm moves up and down like it should so guessing the fault lies elsewhere, anyone any ideas? Quote Link to comment Share on other sites More sharing options...
RobUK Posted January 17, 2016 Share Posted January 17, 2016 (edited) Is it sticking though? Or does it naturally fall down? Does the indicator move if you move the float switch? Have you taken the instrument cluster apart to see if it's stuck? Edited January 17, 2016 by RobUK (see edit history) Quote Link to comment Share on other sites More sharing options...
jonc Posted January 17, 2016 Share Posted January 17, 2016 I have just been through an issue with my fuel tank gauge (Facelift cluster) Mine would not move no matter what the fuel level was however the low fuel light worked so i knew when i was getting low. Firstly I checked the sender unit resistance moved as the potentiometer moved on the sender. Once I had proven this I then did the same but at the other end of the loom (where it connects into the cluster onto the plugs). This then proved the wiring and the sender was good. I then disconnected the plug on top of the fuel pump hanger and turned on the ignition. Fuel gauge should move towards empty. Be aware this moves slowly. I then connected a jumper (I used a 12V test lamp) across terminals 2 and 3 on the pump hanger plug on the loom side (not the hanger socket) and turned on the ignition. The fuel gauge should read full deflection (ie Full). My gauge didn't move either way so I knew it was toast. There are a few resistances you can take across +,- and F on the fuel meter and they are listed in the BE repair manual but I knew my meter was toast from the above tests. I bought a second hand unit from a member on here and alls well again. Just make sure you Sync your sender and fuel tanks gauge if you do have to change the gauge. The cluster needs stripping down to change the individual gauges but its not difficult. If you find that it is your gauge let me know and I will take some pictures of a cluster strip down to gauge level. Hope this helps Quote Link to comment Share on other sites More sharing options...
Big Mark Posted February 15, 2016 Author Share Posted February 15, 2016 First post edited as I forgot to mention that I'd had the battery disconnected for a couple of days, so could this of caused something to reset? The reason I ask is that when I disconnected the battery the car probably had 1/3rd of a tank. And I noticed this weekend that after doing 200 miles that the needle started to move down a bit, so may it somehow of reset itself so that it thinks 1/3 full is actually a full tanks position? Does the signal from the tank go straight to the gauge or via the ECU? Quote Link to comment Share on other sites More sharing options...
Chris Wilson Posted February 15, 2016 Share Posted February 15, 2016 Disconnect the plug at the tank top. If the gauge still reads full there's a short on the wire between gauge and sender unit plug. Quote Link to comment Share on other sites More sharing options...
Big Mark Posted February 15, 2016 Author Share Posted February 15, 2016 Disconnect the plug at the tank top. If the gauge still reads full there's a short on the wire between gauge and sender unit plug. Thanks Chris, that's my weekend job. Not looking forward to trying to to source a short tho. Does the wire run down ithe passenger side inside the car in the bundle under the door sill cover? Quote Link to comment Share on other sites More sharing options...
Chris Wilson Posted February 15, 2016 Share Posted February 15, 2016 Apart from thinking if you might have been drilling / screwing anything down and it gives a clue as where to look, if it *IS* shorted I would just run a new wire from behind the dash to the tank. I am not sure which side the gauge wire runs, but I if it continues to run with the pump wiring, that's on the left hand side of the car. Quote Link to comment Share on other sites More sharing options...
Big Mark Posted February 15, 2016 Author Share Posted February 15, 2016 Well i did have the seats and carpet out just before it all went tits up but no idea what might of happened. Oh well, gives me something to do. Quote Link to comment Share on other sites More sharing options...
Chris Wilson Posted February 15, 2016 Share Posted February 15, 2016 If you are short of something to do, buy an Alfa Romeo Quote Link to comment Share on other sites More sharing options...
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