Ecosse Posted July 14, 2020 Report Share Posted July 14, 2020 Afternoon All, After 63-years my fuel gauge has decided it has had enough, it still works, but needs a flick on the glass to spring into action and seems to read low. I can get a replacement for £75, but just wondered if anyone has any hints as to how I can perhaps remedy the situation before purchasing a replacement. Thanks. Cliff Quote Link to post Share on other sites
rodofcv Posted July 14, 2020 Report Share Posted July 14, 2020 May I suggest you get in touch with 'Lebro', ace fuel gauge fixer? Rod Quote Link to post Share on other sites
TwinCamJohn Posted July 15, 2020 Report Share Posted July 15, 2020 Actually I have been searching on the forum to see if there was a tutorial for checking the fuel gauge sender. Couldn't find anything. Quote Link to post Share on other sites
RobH Posted July 15, 2020 Report Share Posted July 15, 2020 (edited) 14 minutes ago, TwinCamJohn said: Actually I have been searching on the forum to see if there was a tutorial for checking the fuel gauge sender For a TR3A the sender resistance is 70 Ohms when full and zero when empty, according to this site: https://www.britishcarforum.com/bcf/showthread.php?33663-fuel-gauge-sender-TR3A Edited July 15, 2020 by RobH Quote Link to post Share on other sites
John Morrison Posted July 15, 2020 Report Share Posted July 15, 2020 With the key turned on, take the supply wire to the sender, easy pull without disturbing the tank, and put the wire to earth, if the guage swings to full, the guage is fine and the sender is U/S, If the guage does not steadily move to full, then it is the suspect, probobly just needs a clean. John. Quote Link to post Share on other sites
RobH Posted July 15, 2020 Report Share Posted July 15, 2020 (edited) 26 minutes ago, John Morrison said: With the key turned on, take the supply wire to the sender, easy pull without disturbing the tank, and put the wire to earth, if the guage swings to full, the guage is fine Not on the early cars I think John. I believe they work the other way round. Your description is right for a meter with bimetallic operation, maybe not for the moving-magnet meters in 2s and 3s. ? This link is from the dark side but the info on troubleshooting is good: http://www.mgaguru.com/mgtech/electric/fg104.htm Edited July 15, 2020 by RobH Quote Link to post Share on other sites
Lebro Posted July 15, 2020 Report Share Posted July 15, 2020 21 hours ago, rodofcv said: May I suggest you get in touch with 'Lebro', ace fuel gauge fixer? Rod Happy to take a look. Bob. Quote Link to post Share on other sites
TwinCamJohn Posted July 15, 2020 Report Share Posted July 15, 2020 2 hours ago, RobH said: Not on the early cars I think John. I believe they work the other way round. Your description is right for a meter with bimetallic operation, maybe not for the moving-magnet meters in 2s and 3s. ? This link is from the dark side but the info on troubleshooting is good: http://www.mgaguru.com/mgtech/electric/fg104.htm That link says you can't use a digital meter. Why would that be ? Quote Link to post Share on other sites
Ecosse Posted July 15, 2020 Author Report Share Posted July 15, 2020 Good Afternoon All, Thanks for the info. The gauge swings to full with the feed cable disconnected, and the gauge works, albeit slowly to full, when the operating lever in the tank is manually lifted using a piece of bent rod. I hope it is not the sender, which was replaced a number of years ago when I installed a new fuel tank, the issue is getting the sender out as I have a fireproof bulkhead installed. Bob, Would dismantling the gauge and giving it a clean and some WD40 be a good idea, unfortunately we live at opposite ends of the UK. Thanks again to all. Regards, Cliff Quote Link to post Share on other sites
RobH Posted July 15, 2020 Report Share Posted July 15, 2020 (edited) I guess he is saying that because when you are looking at a quickly varying voltage a digital meter shows just a blur of numbers. Much easier to watch movement on a needle. Edited July 15, 2020 by RobH Quote Link to post Share on other sites
Richardtr3a Posted July 15, 2020 Report Share Posted July 15, 2020 Send it to Bob who worked on my gauge . I sent him the gauge and the sender and now it all works properly. There are these experts on the forum and we are very lucky. Send it by post quick Richard & B Quote Link to post Share on other sites
Ian Vincent Posted July 15, 2020 Report Share Posted July 15, 2020 If a flick on the glass makes the gauge work, I don't see how it can be the sender. I used the info on the mgaguru page to sort out my fuel gauge. When I bought the car it had a sender and gauge from a later car. I acquired the correct gauge and then found that the sender was back to front. Being a cheapskate I took the sender apart and reversed the wiring on the rheostat and re-calibrated it to the gauge. It now works fine albeit the needle stays on full for a long time and once it starts to move it moves quite quickly down to quarter tank at which point you need to be looking for a refuel stop. Rgds Ian Quote Link to post Share on other sites
Adam Blackaby Posted July 15, 2020 Report Share Posted July 15, 2020 Thanks RobH. I've just ventured into the 'Dark side' and purchased an MGA. At least I'm not alone in this travesty, one of our previous chairmen had one for many years, albeit I recall a Twin Cam Coupe. Guess what, switch the ignition on and the fuel gauge zooms over to full. Did look at the wsm for the car but unlike the TR equiv which explains how to check for faults in the sender unit, that published by BMC for the MGA doesn't even acknowledge the presence of fuel gauge or sender unit. Your link to MGAGuru was most timely We TR'ists dont know how lucky we are! Quote Link to post Share on other sites
BlueTR3A-5EKT Posted July 15, 2020 Report Share Posted July 15, 2020 7 minutes ago, Adam Blackaby said: Thanks RobH. I've just ventured into the 'Dark side' and purchased an MGA. At least I'm not alone in this travesty, one of our previous chairmen had one for many years, albeit I recall a Twin Cam Coupe. Guess what, switch the ignition on and the fuel gauge zooms over to full. Did look at the wsm for the car but unlike the TR equiv which explains how to check for faults in the sender unit, that published by BMC for the MGA doesn't even acknowledge the presence of fuel gauge or sender unit. Your link to MGAGuru was most timely We TR'ists dont know how lucky we are! Adam, you have gone to the dark side! Motoring Grimly The MGA Guru is exceptionally helpful. Good fault finding and info for all older British car owners. Peter W Quote Link to post Share on other sites
John McCormack Posted July 16, 2020 Report Share Posted July 16, 2020 If it works with a flick of the gauge it is probably just the earth for the gauge. Take the gauge out and clean up everything. It should be fine after that. Quote Link to post Share on other sites
JeffR Posted July 16, 2020 Report Share Posted July 16, 2020 +1 Quote Link to post Share on other sites
MilesA Posted July 17, 2020 Report Share Posted July 17, 2020 +2 Sometimes an extra earth cable from under the knurled nut to somewhere suitable on the body helps. Miles Quote Link to post Share on other sites
Ecosse Posted July 18, 2020 Author Report Share Posted July 18, 2020 Good Afternoon All, Thanks to all who proffered advice on my problem. Following a stripdown and clean, plus an additional earth wire normal service has been resumed. I now have £75 to spend elsewhere. Regards, Cliff Quote Link to post Share on other sites
John McCormack Posted July 20, 2020 Report Share Posted July 20, 2020 On 7/19/2020 at 12:39 AM, Ecosse said: Good Afternoon All, Thanks to all who proffered advice on my problem. Following a stripdown and clean, plus an additional earth wire normal service has been resumed. I now have £75 to spend elsewhere. Regards, Cliff Pleased to be able to help. 44 years in a TR2 I learnt something and am still learning which is the great thing about these forums. Quote Link to post Share on other sites
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