PaulAnderson Posted August 26, 2008 Report Share Posted August 26, 2008 Just had a great day on Sunday down in Yorkshire (from Northumbria group) starting with a show at Swainby then on to Harrogate and on the very indirect route back home (good weather so why take the A1) I noticed the temperature gauge bottoming out just as my partner pulled the heater on. Strange I thought and when she pushed the heater back in the temperature came back up. Very strange. After stopping and checking things out including accessible connections but finding nothing untoward I later noticed that the fuel gauge was also going up and down in tune. Ahh I thought, the heater operation must have been a co-incidence and it must be the voltage regulator on its way out. My question is, can these have erratic behaviour failing, should it fail totally at once or could it be something else? Note, I recently (300 miles ago) upgraded from dynamo to a 40 Amp lightweight alternator but that should not be the cause should it? Regards, Paul Quote Link to post Share on other sites
Dazzer Posted August 26, 2008 Report Share Posted August 26, 2008 Just had a great day on Sunday down in Yorkshire (from Northumbria group) starting with a show at Swainby then on to Harrogate and on the very indirect route back home (good weather so why take the A1) I noticed the temperature gauge bottoming out just as my partner pulled the heater on. Strange I thought and when she pushed the heater back in the temperature came back up. Very strange. After stopping and checking things out including accessible connections but finding nothing untoward I later noticed that the fuel gauge was also going up and down in tune. Ahh I thought, the heater operation must have been a co-incidence and it must be the voltage regulator on its way out. My question is, can these have erratic behaviour failing, should it fail totally at once or could it be something else? Note, I recently (300 miles ago) upgraded from dynamo to a 40 Amp lightweight alternator but that should not be the cause should it? Regards, Paul Hi Paul We have exactly the same fault as you have described and something that is intermittent in our case. Spookily we live near Harrogate, perhaps its on a ley line? I personally believe its due to a loose connection, as we have a new voltage regulator fitted, but with all the shaking Steven's action going on in a TR4 something's bound to shake loose. Although opening the heater will drop the engine temp noticeably anyway as the heater matrix will act as a secondary radiator to cool the engine, so perhaps a combination of temp dropping and loose connection. I'd drop the centre gauge panel down and check everythings tight, All the best Darren Quote Link to post Share on other sites
BrianC Posted August 27, 2008 Report Share Posted August 27, 2008 I noticed the temperature gauge bottoming out just as my partner pulled the heater on. Strange I thought and when she pushed the heater back in the temperature came back up. Do you mean that she just opened the valve or that she turned on the fan? If the former, then it's probably not a problem with the voltage stabilisor. If the latter, then it probably is an electrical problem. Personally, I'd suspect the alternator - I never trust these things and stick with the old technology dynamo which I do (sort of ) understand. Probably worth swapping the stabilisor for a known good one (not necessarily new as these are often duff as well ) as an easy first attempt at eliminating the culprit. Quote Link to post Share on other sites
richardix Posted July 8, 2009 Report Share Posted July 8, 2009 Hi, the voltage regulator consists of a bi-metal. Normally it is closed and 14 Volts (The battery voltage) is on the output. The bi-metal warms up and opens, so the output voltage drops to 0 Volts. This means that a block wave exists between 14 Volts and 0 Volts with an average of 10 volts. Because the temperature gauge and fuel gauge are relatively slow in reacting on a difference in voltage, you will not see it moving. But at low engine speeds or when equipment as a fan turns on, the average voltage can drop over the voltage regulator and can result in gauge `movement`. Of coarse I don´t know if above description occurs, but maybe it helps in understanding your electrical system. The voltage regulator is only applicable to the temperature and fuel gauge. At my own car I replaced the old voltage regulator with a modern, silicon voltage regulator. This means the output is always 10 volts. kind regards, Richard Quote Link to post Share on other sites
monty Posted July 8, 2009 Report Share Posted July 8, 2009 Just had a great day on Sunday down in Yorkshire (from Northumbria group) starting with a show at Swainby then on to Harrogate and on the very indirect route back home (good weather so why take the A1) I noticed the temperature gauge bottoming out just as my partner pulled the heater on. Strange I thought and when she pushed the heater back in the temperature came back up. Very strange. After stopping and checking things out including accessible connections but finding nothing untoward I later noticed that the fuel gauge was also going up and down in tune. Ahh I thought, the heater operation must have been a co-incidence and it must be the voltage regulator on its way out. My question is, can these have erratic behaviour failing, should it fail totally at once or could it be something else? Note, I recently (300 miles ago) upgraded from dynamo to a 40 Amp lightweight alternator but that should not be the cause should it? Regards, Paul Hi Paul, Had exactly the same thing happen to me a few months ago. Got a new regulator/stabiliser from TRGB & been ok since. Good luck, Monty. Quote Link to post Share on other sites
Smokey Posted July 9, 2009 Report Share Posted July 9, 2009 I had incorrect readings on the fuel gauge and other gauges on my TR250 many years ago, and a new voltage stabilizer fixed it, so I believe the rregulators can fail partially or gradually. I've fitted a solid state regulator on my current TR4 - so far, so good. Quote Link to post Share on other sites
Kiwifrog Posted July 9, 2009 Report Share Posted July 9, 2009 (edited) Just to help me clear things up Voltage regulator : Black box fitted under bonnet on cars fitted with dynamo to regulate the DC current produced by the Dynamo. Not required with alternator equipped cars as this is done within the alternator Voltage stabilizer. Small item fitted under dashboard which stabilizes the erratic current produced by the cars charging circuit so that the dash gauge needles dont wobble about like a drunk on a bicycle Cheers Alan Edited July 9, 2009 by Kiwifrog Quote Link to post Share on other sites
67_gt6 Posted July 9, 2009 Report Share Posted July 9, 2009 Hi, these are voltage satabilizer issues, not regulator - if your regulator was seriously out then your battery would either be boiling or going flat. I would advise replacing the standard stabilizer with a solid state one from eBay, cost about 5 quid. andy Quote Link to post Share on other sites
Smokey Posted July 9, 2009 Report Share Posted July 9, 2009 Apologies - brain fade. I meant voltage stabilizer, on the right wall in the LHD passenger footwell. On the TR250, it was attached to the speedometer. Quote Link to post Share on other sites
MikeF Posted July 12, 2009 Report Share Posted July 12, 2009 Apologies - brain fade. I meant voltage stabilizer, on the right wall in the LHD passenger footwell. On the TR250, it was attached to the speedometer. It's also possible that the terminals to the stabilizer are badly oxidised, this can give variations very similar to a failed unit. So suggest you first just slide the connectors on and off a few times/ try a little emery paper. Mike Quote Link to post Share on other sites
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