aardvark Posted November 3, 2021 Report Share Posted November 3, 2021 Hello all. I’ve just changed my fuel tank and the tank sender. Problem I now have is that the gauge reads full all the time even though it is near empty. I suspect a ground somewhere. Where should I look? cheers dave Quote Link to post Share on other sites
RobH Posted November 3, 2021 Report Share Posted November 3, 2021 (edited) To start with you could disconnect the wire from the sender at the tank. If the gauge goes to empty, the short is somewhere in the sender itself or its connector, or perhaps the sender arm isn't free and has stuck in the up position. If it stays showing full when you remove the wire, the short is somewhere in the wire from the gauge. If that is the case and you haven't disturbed anything except around the tank, it is probably in that area. Edited November 3, 2021 by RobH Quote Link to post Share on other sites
aardvark Posted November 4, 2021 Author Report Share Posted November 4, 2021 Thanks for your response. I removed the earth and the tank stayed full. I removed the signal and the gauge went to zero. I put the old tank next to the new in the boot and wired that up and the gauge works as it should so I think the problem must be with the new sender. I thoroughly tested the sender on the tank before fitting. I can’t see that I have installed it wrong. Is there anything else I can check before I have to rip the new tank out again and change the sender? incidentally, the new sender is the mega ££, ultra reliable (!) one from the south west. cheers dave Quote Link to post Share on other sites
RobH Posted November 4, 2021 Report Share Posted November 4, 2021 If you have a multimeter with a resistance range, you could try measuring the resistance of the sender between its output connection and earth. It should be somewhere in the approximate range 20 Ohms (full) to 200 Ohms (empty) I believe . If it is dead short then there is definitely a problem in the sender. Quote Link to post Share on other sites
FatJon Posted November 4, 2021 Report Share Posted November 4, 2021 Have you got the two wires crossed at the sender end? Quote Link to post Share on other sites
aardvark Posted November 4, 2021 Author Report Share Posted November 4, 2021 2 hours ago, FatJon said: Have you got the two wires crossed at the sender end? No, tried both ways with the same result. Quote Link to post Share on other sites
aardvark Posted November 4, 2021 Author Report Share Posted November 4, 2021 3 hours ago, RobH said: If you have a multimeter with a resistance range, you could try measuring the resistance of the sender between its output connection and earth. It should be somewhere in the approximate range 20 Ohms (full) to 200 Ohms (empty) I believe . If it is dead short then there is definitely a problem in the sender. I tested the resistance before installing it. Tested again once installed and on the bench. Once in the car it’s stopped working. That’s why I’m thinking that maybe it’s earthing differently somehow. Quote Link to post Share on other sites
Waldi Posted November 4, 2021 Report Share Posted November 4, 2021 Or it could still be stuck in the most upper position. Quote Link to post Share on other sites
aardvark Posted November 4, 2021 Author Report Share Posted November 4, 2021 I’ve had a coat hanger in there moving it around so it’s not stuck. Looks like I will be taking the tank out again and throwing away a brand new sender unit ! Quote Link to post Share on other sites
harlequin Posted November 4, 2021 Report Share Posted November 4, 2021 Richard Have you tried running an earthing wire from the tank to the battery earth point George Quote Link to post Share on other sites
aardvark Posted November 4, 2021 Author Report Share Posted November 4, 2021 Yep, tried that, same result, full deflection. Quote Link to post Share on other sites
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