ronhatch Posted June 29, 2020 Report Share Posted June 29, 2020 Hi all, My temp gauge starts off in the cold position and as the engine warms it starts to move, so far so good, but it continues all the way to 120c. The actual temp at the thermostat housing is 85c . It is a new sender unit. Any ideas from the sages Regards Ron Quote Link to post Share on other sites
stuart Posted June 29, 2020 Report Share Posted June 29, 2020 34 minutes ago, ronhatch said: Hi all, My temp gauge starts off in the cold position and as the engine warms it starts to move, so far so good, but it continues all the way to 120c. The actual temp at the thermostat housing is 85c . It is a new sender unit. Any ideas from the sages Regards Ron Wrong sender by the sound of it. Stuart. Quote Link to post Share on other sites
ronhatch Posted June 29, 2020 Author Report Share Posted June 29, 2020 Hi Stuart, I had that idea and I have just changed the sender to an old one from another tr4 engine and the reading is the same, although the old one was longer that the new one. Do either I've got 2 duff/wrong senders or something else is happening. Also can the instruments be taken apart for cleaning ? Regards Ron Quote Link to post Share on other sites
RobH Posted June 29, 2020 Report Share Posted June 29, 2020 Is the fuel gauge reading correctly Ron? If that is high as well you might have a failed instrument voltage stabiliser. Quote Link to post Share on other sites
NigelH Posted June 29, 2020 Report Share Posted June 29, 2020 Hi Ron, Try stripping back and replacing the spade connector on the wire connection too..it may be causing a high resistance in the circuit.. Nigel H. Quote Link to post Share on other sites
Lebro Posted June 29, 2020 Report Share Posted June 29, 2020 +1 for checking the voltage stabiliser Bob. Quote Link to post Share on other sites
ronhatch Posted June 29, 2020 Author Report Share Posted June 29, 2020 The fuel gauge is working ok and it is a new loom so I'm at a loss, I will change the gauge for another tomorrow but I know this is a fahrenheit unit Cheers all Ron Quote Link to post Share on other sites
ronhatch Posted June 29, 2020 Author Report Share Posted June 29, 2020 I was also thinking of changing the stabiliser anyway for an electronic type, the original is 58 years old any recommendations ? Regards Ron Quote Link to post Share on other sites
Rawls Posted June 29, 2020 Report Share Posted June 29, 2020 Hi Ron, I’ve had the same issues as you describe, I recommend one of these units. Mike https://www.ebay.co.uk/itm/254122488000 Quote Link to post Share on other sites
ronhatch Posted June 29, 2020 Author Report Share Posted June 29, 2020 cheers Mike Quote Link to post Share on other sites
Steve Priest Posted June 29, 2020 Report Share Posted June 29, 2020 I’ve not tried it myself, however the gauge is adjustable. Need to rule out everything else first before going down this route though! Steve Quote Link to post Share on other sites
ronhatch Posted June 29, 2020 Author Report Share Posted June 29, 2020 Interesting Steve do the gauges come apart for cleaning Regards Ron Quote Link to post Share on other sites
ronhatch Posted June 29, 2020 Author Report Share Posted June 29, 2020 I have changed the car to a negative earth alternator system would the affect the gauge ? the ammeter is not working Regards Ron Quote Link to post Share on other sites
RobH Posted June 29, 2020 Report Share Posted June 29, 2020 You might find some useful information in this old thread Ron: https://www.tr-register.co.uk/forums/index.php?/topic/39702-tr4a-temperature-sender-resistance-a-favour/ (The chap talking about 'thyristor' actually means thermistor) The gauges do come apart with care - I believe you have to bend back the tabs on the chrome bezel to remove the glass so you don't want to do that too often. The alternator and polarity change shouldn't have any bearing on this. The temp gauge works on the bimetallic principle so doesn't care about polarity. Your ammeter not working may be because the alternator output has been connected to the wrong end of it. Quote Link to post Share on other sites
ronhatch Posted June 29, 2020 Author Report Share Posted June 29, 2020 Cheers Rob Quote Link to post Share on other sites
Lebro Posted June 29, 2020 Report Share Posted June 29, 2020 The meter is not polarity sensitive, but an electronic voltage stabiliser (if you were to have one) is. I have taken quite a few gauges apart, I find you can usually get the chrome bezel off by twisting it till the tabs line up with slots in the case. If you bend them they are likely to snap off. Bob. Quote Link to post Share on other sites
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