julians Posted July 22, 2001 Share Posted July 22, 2001 The water temp guage has started overreading by about 35-40 degrees, so when the engine is at 80degrees the guage reads 115 degrees ( I know its overreading and not the engine actually overheating because the temp sensor for the ecu is still giving correct results and the fan is coming on at the correct temp). I have replaced the sender with a known good one, but it still gives too high readings. Someone I know suggested the voltage regulator may be duff, where is the voltage regulator, how do I test it, what does it do? and how much is a new one. Cheers Julian Link to comment Share on other sites More sharing options...
EFA Posted July 22, 2001 Share Posted July 22, 2001 A Seven does not have one. I think the gauges have internal regulation. Or those with 3 pins do..... Looks like a duff gauge. Arnie Webb So fat the chassis snapped....wink.gif See Fat Arnies 2 piece Seven here See the Le Mans Trip Website here See the Lotus Seven Club North Kent Website here Edited by - fat arnie on 22 Jul 2001 22:54:51 Link to comment Share on other sites More sharing options...
sjwb Posted July 23, 2001 Share Posted July 23, 2001 I believe that the rectifier / regulator is a component part of the alternator, situated behind the stator and around the armature; Non servicable but re-newable. I would have thought that a reg problem would have manifested itself in more obvious ways, fluid loss from the battery, bright lights, erratic engine, blown fuses et al. Quick check - put a voltmeter across the battery, everything swithed on and run the motor to about 1500 rev. min. You should see about 13 to 14 volts. With all the equipment off, the result should be very similar. Top voltage? No more than 14.5V. I would dearly love to see an automotive electrical charging system without voltage / current regulation. Link to comment Share on other sites More sharing options...
EFA Posted July 23, 2001 Share Posted July 23, 2001 The regulator in the alternator converts the native AC output of the alternator into DC and caps it at 13.8v Most gauges run at 8.0v for full scale deflection. Arnie Webb So fat the chassis snapped....wink.gif See Fat Arnies 2 piece Seven here See the Le Mans Trip Website here See the Lotus Seven Club North Kent Website here Link to comment Share on other sites More sharing options...
julians Posted July 23, 2001 Author Share Posted July 23, 2001 Ah right, will start to dig deeper then. Link to comment Share on other sites More sharing options...
Barry Posted July 23, 2001 Share Posted July 23, 2001 My 1986 Seven has Smiths Instruments, an alternator, and a voltage regulator. The voltage regulator is a small silver coloured box 1.5" x .5" x .5" with 3 blade connectors. It's up behind the dash held in a clip a little like those that hold the flasher and hazard units. With my car, when the voltage regulator is not working properly, the temperature gauge and fuel gauge both read incorrectly (higher). Barry Link to comment Share on other sites More sharing options...
julians Posted July 23, 2001 Author Share Posted July 23, 2001 Hmmm, the plot thickens. My car is a 97 dedion, fuel guage and oil pressure are both reading correctly. Link to comment Share on other sites More sharing options...
sjwb Posted July 23, 2001 Share Posted July 23, 2001 Point of order Mr Chairman! The RECTIFIER converts AC to DC, the REGULATOR controls the (then) DC voltage output of the alternator to match demand. The reg/rectifier is usually encapsulated (according to manufacturer) in the alternator. Doesn't make sense to have a component part of the alternator remotely located. Do the simple things first - check the (dynamic) battery voltage. Never mind the points of a volt, your meter will probably not be that accurate anyway. Link to comment Share on other sites More sharing options...
EFA Posted July 23, 2001 Share Posted July 23, 2001 Mr swjb, You are correct, however, the alternator regulator controls the bettery charging voltage. the instrument regulators control the constant calibration of the instruments when the battery voltage varies. i.e. makes sure you dont get an increase in readings (say water temp) when you compare hot engine running to hot engine not running i.e just switched off. Barrys Smiths instruments will have a separate regulator. I made the assumption we were talking about a car with VDO or the new instruments (I dont recall the name of the manufacturer) Arnie Webb So fat the chassis snapped....wink.gif See Fat Arnies 2 piece Seven here See the Le Mans Trip Website here See the Lotus Seven Club North Kent Website here Link to comment Share on other sites More sharing options...
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