ronhatch Posted January 2, 2019 Report Share Posted January 2, 2019 Hi All, after an enforced lay off from rebuilding my TR4 I finally made sense of the electrics ( sort of ) got the petrol through, and after 45 years it started first time. This was a bit of a surprise as I had only meant to crank it via the solenoid to get some oil in the pots but I had left the ignition on. After the initial shock and some panic ( it was in gear although up on stands ) I had a stupid smile on my gob. After playing around with stopping and starting it to make sure it wasn't a fluke I set about tuning it. I then had to take off the battery lead which was when I noticed a small spark. after eliminating everything I discovered the the new alternator was getting warm by draining power from the battery. I checked all my wiring including the alteration to the control box and all was in order although I had previously noted that the lead to the alternator plug had a small and large brown wire and a small brown and yellow wire, there is also a (spare) large brown and yellow and a small brown and green taped together. I bought the loom from moss or rimmers and specified the alternator variant. Whats wrong ? Any help would be great. (still got a smile on my gob though ) Regards Ron Quote Link to post Share on other sites
RogerH Posted January 2, 2019 Report Share Posted January 2, 2019 Hi Ron, with the alternator you shouldn't have anything in the control box affecting what is going on. The control box is only for the dynamo. Have you got a copy of the Technicalities CD that was being given out many moons ago. It shows how to hook it all up - without the smoke. Roger Quote Link to post Share on other sites
ronhatch Posted January 2, 2019 Author Report Share Posted January 2, 2019 Hi Rodger, thanks for the reply. I did get the technical detail and like others I am just using the old control box to link wires ( A1-A-D ). The battery/alternator current would, I assumed, be controlled by the diode bank in the alternator. When I initially started it by accident the alternator was not connected via the plug and it ran for as long as it took me to get from the engine bay to the ignition switch to turn it off. After plugging in I have tested the alternator current and it is delivering voltage to the battery. could the initial brief start up affect the diode bank ? Regards Ron Quote Link to post Share on other sites
had17462 Posted January 2, 2019 Report Share Posted January 2, 2019 Ron what alternator have you bought ,I am only asking as I bought one of the little Japanese ones for another car and it was doing what yours is doing and couldn't be used . Nick Quote Link to post Share on other sites
peejay4A Posted January 2, 2019 Report Share Posted January 2, 2019 Old wisdom says to not run an alternator open circuit. I’ve never tested the theory but if it holds up you might have blown a diode, which would explain the sparks and heating. You might also have damaged the internal regulator if it has one. Quote Link to post Share on other sites
ronhatch Posted January 2, 2019 Author Report Share Posted January 2, 2019 Hi all, I have just done a diode test and it only registers one way so it would appear to be OK. I bought it off ebay ages ago and it was the one advised for the TR4, can't find the paperwork so I will check which one it is tomorrow. If the alternator is getting warm would it point to a parasitic draw ? Regards Ron Quote Link to post Share on other sites
peejay4A Posted January 2, 2019 Report Share Posted January 2, 2019 Only one diode? Iirc there are usually 9 of them. Quote Link to post Share on other sites
rcreweread Posted January 2, 2019 Report Share Posted January 2, 2019 Ron At the risk of stating the obvious ( or in my own case not), some of the instructions to use the old control box terminals as a junction box don't always make it clear that you have to remove/disconnect the internal electrics /coils. Not doing so causes quite a lot of mayhem!! Don't ask how I know! Cheers Rich Quote Link to post Share on other sites
ronhatch Posted January 3, 2019 Author Report Share Posted January 3, 2019 Hi Rich, I did remove all the guts of the regulator but thanks for the thought. I will take the alternator off today and test all the diodes pete but I did notice last night that the module in the new electronic ignition was clicking as I made and unmade the battery connection, any thoughts ? Regards Ron Quote Link to post Share on other sites
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