nevins Posted October 11, 2013 Share Posted October 11, 2013 Getting fed up now. Recently fitted a recon unit to the car. All was perfect except just now I noticed a funny smell and it's once again making a death drone. Has anyone had any similar problems with their car eating alternators. Could it be caused by a failing tensioner. Quote Link to comment Share on other sites More sharing options...
Guest Roger NE Posted October 11, 2013 Share Posted October 11, 2013 Any excessive Tension issues would only cause the bearings to fail prematurely - it would have no effect on the Alternator windings or electronics. If you're blowing them up, it can only be due to excessive current being drawn . . . and that would only happen due to something going short-circuit Even then, whatever is shorting out would have to be connected with some pretty hefty cable (as I doubt if normal thin cable would carry enough current to destroy the Alternator without catching fire!) Do you have any thick cable going to, say, an aftermarket high-power audio amplifier? Quote Link to comment Share on other sites More sharing options...
nevins Posted October 11, 2013 Author Share Posted October 11, 2013 When I had the unit reconditioned. I had to have everything replaced and he said the bearing had eaten into the shaft. I got no warning lights or anything up. Just a really strong mettalic smell a droning sound and I touched the alternator and burnt my fingers. When I first did the swap I had trouble removing tension off the belt but not as bad putting the belt back on. A quick pull on the belt and I can move the tensioner I'm wondering if this is screwed. Quote Link to comment Share on other sites More sharing options...
safcdixon Posted October 11, 2013 Share Posted October 11, 2013 If you can move the tensioner by hand i would say thats goosed, i know when I put a new belt on after removing the A.C i had to use a power bar to shift the tensioner over to get the belt on Quote Link to comment Share on other sites More sharing options...
nevins Posted October 11, 2013 Author Share Posted October 11, 2013 To remove tension I used two spanners linked but I can move the arm about three inches by pulling the belt. Would a slack tensioner cause this problem I'm having though. Quote Link to comment Share on other sites More sharing options...
nevins Posted October 11, 2013 Author Share Posted October 11, 2013 Previous owner had a sound system in the supra. It has a power cap fitted would this cause issues. Never have the music on loud either so hardlyany drain. Stating to annoy me now as it has to be a simple reason for the problem. Does anyone know if the alternators get hot when running as this has been painted and was wondering if it's the paint burning giving off the smell. Quote Link to comment Share on other sites More sharing options...
listy Posted October 11, 2013 Share Posted October 11, 2013 In that case Gav I'd start by removing the power cap if it's there for no reason. I don't think it's the problem, and agree with the possible short circuit, but it will rule it out at least. Quote Link to comment Share on other sites More sharing options...
nevins Posted October 11, 2013 Author Share Posted October 11, 2013 It's there for a reason mate a full install and not a cheap one. Just the fact I ain't tried it out yet. Needs to be set up as all settings were lost. Cars starting to wind me up now. Quote Link to comment Share on other sites More sharing options...
Guest Roger NE Posted October 12, 2013 Share Posted October 12, 2013 (edited) Forget your Belt Tensioner - if it was too slack the belt would slip when the Alternator was under heavy load - in fact if that had been happening it would have probably saved it from burning out! I would disconnect ALL of the heavy duty wiring to the Amplifier and the Power Cap. I would bet anything that it's either the Amplifier or the Capacitor going virtually short circuit intermittently, and that's what is burning out your Alternator ! Of course it could also be the wires chaffing and shorting to the chassis somewhere, but I think you would see that. I suppose if you have that big a load on the Alternaor, it would also cause its bearings to fail, because it would be really hard to turn when it was delivering that much current ! (it would also be sapping a lot of power from your engine) The hard thing would be identifying what is faulty - to save burning out any more Alternators I would remove them from the car and connect the Amp and Cap to a high power regulated 12V mains supply with current overload protection (which of course you won't have) Oh and by the way, under normal driving with nothing electrical turned on, the Alternator would be cold (although of course heat will be conducted from the engine block) . . . once you turn things on (headlamps, heated rear window) it will start supplying power, and will get warm. But it should never get very hot unless it is supplying silly amounts of continuous high current (due to a short circuit). Just because an Alternator is rated at 100 Amps, doesn't mean it will supply that much current CONTINUOUSLY without burning out - it's just capable of supplying that on peaks. A really high-power amplifier (1000Watts) turned up to full power might draw 100 Amps on peaks, but because it's music, the AVERAGE power will be very much lower, and the Alternator could stand that. It could NOT cope with supplying a continuous 100 Amps into a faulty capacitor, amplifier or short-circuit ! Edited October 12, 2013 by Roger NE (see edit history) Quote Link to comment Share on other sites More sharing options...
nevins Posted October 12, 2013 Author Share Posted October 12, 2013 Cheers mate will disconnect it when I go out and see if it improves. Quote Link to comment Share on other sites More sharing options...
nevins Posted October 12, 2013 Author Share Posted October 12, 2013 Right then audio live has been removed from the car. Battery had 12.6v when running went up to 14.1v. Less than two minutes running and droaning sound got louder and the burning smell was present. Quote Link to comment Share on other sites More sharing options...
Guest Roger NE Posted October 12, 2013 Share Posted October 12, 2013 Well if that's the case some other wire must be shorting out somewhere If so, the burning you can smell is probably the insulation on the offending cable melting ! Try feeling the various cables all around the car . . . none of them should feel hot, so if any are, that's your offending cable. (you may need to remove the dash under tray to access some of them) The only thing I find strange is that MOST cables go through suitable fuses for what they're feeding (10 - 30A) . . . but it sounds like something is drawing about 100 Amps from your Alternator - which is why I suspected a thick cable connected straight to your battery - like to an aftermarket amplifier. I wonder if the Thick cable that feeds the Starter Motor could be shorting to earth inside the Solenoid casing when in the off position? If possible, I would try and unbolt that cable once you've started the engine, and see if the heat and smell stops (but you need to do it WITHOUT accidentally disconnecting the battery!) You could try feeling that cable to see if it's warm . . . Quote Link to comment Share on other sites More sharing options...
nevins Posted October 12, 2013 Author Share Posted October 12, 2013 Starter wires are cold nothing odd about them. The smell is from under bonnet not internal mate. Plus with engine off and sticking your head down the engine it's 100% where the smell is and the fact you burn your hand touching it. Surely my warning lights shouldld be coming up for the charge system. Quote Link to comment Share on other sites More sharing options...
Guest Roger NE Posted October 12, 2013 Share Posted October 12, 2013 (edited) Firstly if the voltage across the battery is 14.1 V with the engine running then the Alternator is working OK (at least for now!) - that's why you don't have a No Charge warning light. Well if the burning smell is from under the bonnet it could just be coming from the Alternator (if it's being severely overloaded) . . . or it could be some wiring under the bonnet that is cooking, due to feeding the short circuit. If the smell IS just coming from the Alternator you still need to identify what cable is drawing a massive amount of current . . . and whatever cable it is will be getting hot. (Ever felt a mains extension cable with a 3kW heater plugged in the end? That's with just 13 Amps going through it!) Thinking about it, I suppose the Starter Cable is SO thick it could still be causing a massive current load (if there was a partial short at the other end) WITHOUT getting that hot . . . so if possible I would still try disconnecting it. The other question is - have you been doing ANY work on the car just before this all started happening that could have caused a cable to get trapped? Edited October 12, 2013 by Roger NE (see edit history) Quote Link to comment Share on other sites More sharing options...
Guest Roger NE Posted October 12, 2013 Share Posted October 12, 2013 Just thought of something else to try as a test . . . Disconnect the main thick wire from the Alternator (and insulate it to stop it shorting) Then run the engine . . . presuming there is a massive short circuit somewhere the battery should get flat VERY quickly Quote Link to comment Share on other sites More sharing options...
nevins Posted October 12, 2013 Author Share Posted October 12, 2013 No work just died. Replaced the alternator while mine was reconditioned that failed now this ones playing up. Quote Link to comment Share on other sites More sharing options...
Guest Roger NE Posted October 13, 2013 Share Posted October 13, 2013 (edited) What are you saying - that you ran the engine with the Alternator disconnected, and the battery went flat really quickly? If so, that PROVES that the Alternator is working fine, and that you have a SHORT in your car's electrics somewhere! (The engine should run for hours without the Alternator connected) But when you connect the Alternator it is struggling to provide the high current your Short Circuit is causing, which is why it is getting so hot (and presumably causing the cooking smell) Until you find that Short Circuit you will keep destroying Alternators ! I think you need to find a mate who understands Electronics to come and help you find the Short. Edited October 13, 2013 by Roger NE (see edit history) Quote Link to comment Share on other sites More sharing options...
nevins Posted October 13, 2013 Author Share Posted October 13, 2013 No what I'm saying is the alter stir failed so it was replaced. The car had no previous work done before the problems. Quote Link to comment Share on other sites More sharing options...
Guest Roger NE Posted October 13, 2013 Share Posted October 13, 2013 OK . . well I suggest you first try what I suggested, and report back (ie disconnect the main Alternator cable and run the engine to see how long the battery lasts (measure the voltage across it . . . I'd cut the engine once it drops to 10 Volts) Quote Link to comment Share on other sites More sharing options...
Guest Budz86 Posted October 13, 2013 Share Posted October 13, 2013 Any chance of borrowing a known working alt. and swapping them at a meet? Also, what amp/volt rating is your battery? If that is knackered, you car will be relying on the alt to power everything. Quote Link to comment Share on other sites More sharing options...
nevins Posted October 13, 2013 Author Share Posted October 13, 2013 Battery is holding charge and taking charge. With this weather at the moment it can sit there lol Quote Link to comment Share on other sites More sharing options...
Guest Roger NE Posted October 13, 2013 Share Posted October 13, 2013 (edited) what amp/volt rating is your battery? If that is knackered, you car will be relying on the alt to power everything. Sorry, but that is irrelevant. The Battery doesn't power anything - once the engine is running the Alternator powers everything. The Battery is only there to a) start the car, or power the lights etc when the engine isn't running and b) smooth out the pulsing output of the Alternator into proper D.C. Also, as I pointed out, your Alternator is clearly working, or you wouldn't have the Voltage readings you have mentioned. (and given that you have cooked TWO Alternators now, anyone would be daft to lend you theirs!) Nevins if you don't want to listen to advice from qualified people who are trying to help, and try things to help diagnose your fault, you're just going to keep burning out Alternators ! Edited October 13, 2013 by Roger NE (see edit history) Quote Link to comment Share on other sites More sharing options...
nevins Posted October 13, 2013 Author Share Posted October 13, 2013 Where have I said I'm not listening to advise? You can clearly see that I have removed the audio as you suggested and then said it's sitting there due to weather. Quote Link to comment Share on other sites More sharing options...
nevins Posted October 13, 2013 Author Share Posted October 13, 2013 Plus I have not asked anyone to supply an alternator. So I don't know where you got that from. Quote Link to comment Share on other sites More sharing options...
Guest Roger NE Posted October 13, 2013 Share Posted October 13, 2013 No, it was the other guy suggesting you borrow another working alternator ! OK mate, sorry . . . it just felt like you weren't listening LOL ! It's frustrating trying to diagnose faults at a distance As I say, I'm pretty sure the problem is NOT your Alternator, but something faulty drawing a LOT of current, or a short circuit. Try that test of disconnecting the Alternator and running the engine when you get a chance. Quote Link to comment Share on other sites More sharing options...
Recommended Posts
Join the conversation
You can post now and register later. If you have an account, sign in now to post with your account.
Note: Your post will require moderator approval before it will be visible.