James67 Posted December 28, 2015 Report Share Posted December 28, 2015 I have just fitted a new alternator to my TR5, when the engine is running with the alternator not plugged in it runs silently but when you plug it in it makes I high pitch tone. ??? Could anyone shed some light on this, it's the first time I have come across it James......................... Quote Link to post Share on other sites
barkerwilliams Posted December 28, 2015 Report Share Posted December 28, 2015 James, Before you look for complicated solutions, when plugged it it will be under load and the belt will tighten into the pulley. Could it just be that? Is it possible to run a little water & washing up liquid over the pulley to act as a temporary lubricant to see if it changes? Alan Quote Link to post Share on other sites
James67 Posted December 28, 2015 Author Report Share Posted December 28, 2015 Hi Alan I have put some silicon spray on the belt.. But when the engine is running with the alternator not plugged in it runs silently but when you plug it in it makes I high pitch tone Quote Link to post Share on other sites
peejay4A Posted December 28, 2015 Report Share Posted December 28, 2015 All the time or just when charging hard after starting the engine? They can "sing" under load. Quote Link to post Share on other sites
James67 Posted December 28, 2015 Author Report Share Posted December 28, 2015 Hi Peat It's all the time so I have put the battery on charge. I had a meter on it and it was shoeing 14.3v off lode. James Quote Link to post Share on other sites
john.r.davies Posted December 28, 2015 Report Share Posted December 28, 2015 Thinking laterally, is it not the alt. but its fitting? New pulley? Correct size? Out of line? Or a water pump problem? John Quote Link to post Share on other sites
RobH Posted December 28, 2015 Report Share Posted December 28, 2015 More than likely this is due to the belt not running properly because the alternator pulley is out of line with the crank. Quote Link to post Share on other sites
Grahamgl Posted December 28, 2015 Report Share Posted December 28, 2015 Surely, if the noise was caused by pulley mis-alignment, then the noise would be present when the alternator was not plugged in. Graham Quote Link to post Share on other sites
SpitFireSIX Posted December 28, 2015 Report Share Posted December 28, 2015 Hi, When the alternator is under-load you will get the belt noise if the pulleys are not lined up correct or the belt is wrong. Under no-load i.e plug removed the alternator pulley is not loaded. Don't disconnect the plug and run the engine though, you risk kaputing the alternator as I have done. I had the wine for a year and loved the sound! People asked if I had a super charger. Belt snapped. New one fitted and now no noise..I did shim it as much as possible and am sure the washers are in the correct place, but the luvly noise has gone. Cheers, Iain. Quote Link to post Share on other sites
James67 Posted December 28, 2015 Author Report Share Posted December 28, 2015 Hi John No all in line with each other and all running well. As Graham said when it's not plugged in runs silent........... plug it in and i get a high pitch ton from the back of the alternator James Go me well stumped Quote Link to post Share on other sites
Peter Cobbold Posted December 28, 2015 Report Share Posted December 28, 2015 (edited) ".....from the back of the alternator." Try googling this string: alternator rectifier diode whine -it might be the rectifier circuit making the noise: http://us.lexusownersclub.com/forums/topic/25049-alternator-warning-signs/ Peter but have never experienced it myself.. Edited December 28, 2015 by Peter Cobbold Quote Link to post Share on other sites
James67 Posted December 29, 2015 Author Report Share Posted December 29, 2015 Winner Winner chicken dinner Yep it terms out to be the rectifier circuit, it looks like one of the diode is faulty. So back to the supplier what a faff. You do have to love them (the supplier) I phoned them to explain the problem that I was having and was met with mmmmm are you sure it has been put on the car right, did you get the part from us? when did it arrive and the best one (bearing in mine he is talking to a customer (Me) well that's a new one, haven't herd that be for I will have to put that one the book. Shame I was not in the show room it would not have been the book I would have tried to put it in But thanks to all who have helped on this one James.............................. Quote Link to post Share on other sites
peejay4A Posted December 29, 2015 Report Share Posted December 29, 2015 Remember not to run the new one without the electrics connected. The regulator doesn't like it. Quote Link to post Share on other sites
James67 Posted December 29, 2015 Author Report Share Posted December 29, 2015 R Did not know that James.......................... Quote Link to post Share on other sites
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