kevinr Posted October 8, 2008 Share Posted October 8, 2008 Can anyone tell me how to test my alternator, ie where to put the voltmeter terminals, and what I'm lookiing for? I read references to live wires out the back, but mine doesn't seem to have one, just an earth wire and a couple more small ones...what am I missing. he alternator part number is AMR4247 if that's useful. Thanks Quote Link to comment Share on other sites More sharing options...
Les Henson Posted October 8, 2008 Share Posted October 8, 2008 With the engine switched off - take a reading from the battery terminals - it should read slightly more than 12v (12.2 I think). Start the engine and it should rise to 13.4v (or thereabouts). No earth wire - that's the main live-the pillar that it's connected to is actually insulated from the alternator body. Les. Quote Link to comment Share on other sites More sharing options...
Matt Neale Posted October 8, 2008 Share Posted October 8, 2008 With the engine switched off - take a reading from the battery terminals - it should read slightly more than 12v (12.2 I think). Start the engine and it should rise to 13.4v (or thereabouts).No earth wire - that's the main live-the pillar that it's connected to is actually insulated from the alternator body. Les. That should actually be 14.4v at no load. If it's much less than that, it's not charging properly. Matt Quote Link to comment Share on other sites More sharing options...
FridgeFreezer Posted October 8, 2008 Share Posted October 8, 2008 That should actually be 14.4v at no load. If it's much less than that, it's not charging properly. That rather depends - some alts charge at 13.4-13.8v and some at 14.4v. Often they'll have it written on them. Quote Link to comment Share on other sites More sharing options...
Matt Neale Posted October 8, 2008 Share Posted October 8, 2008 That rather depends - some alts charge at 13.4-13.8v and some at 14.4v. Often they'll have it written on them. They do Fridge - but this (AMR4247) should be a 100amp unit as fitted to the 300 Tdi, and (I think) the P38 V8.... so a fairly recent Alternator. None of the ones I've come across have charged at less than 14 volts.... All the best, Matt Quote Link to comment Share on other sites More sharing options...
reedx Posted October 8, 2008 Share Posted October 8, 2008 Test the alternator voltage (carefully) at the alternator itself. A low voltage measured at the battery could be the result of cable problems. You don't want to be changing alternator if there's nothing wrong with it. Check the voltage between the case of the alternator and the B+ wire. Colin www.REEDX.net/landrover Quote Link to comment Share on other sites More sharing options...
kevinr Posted October 8, 2008 Author Share Posted October 8, 2008 thanks for the replies. one other question, where would I find my voltage regulator? is it in the alternator, or mounted externally somewhere? Quote Link to comment Share on other sites More sharing options...
reedx Posted October 8, 2008 Share Posted October 8, 2008 Luke did a write-up about changing the regulator on a A127 alternator. http://forums.lr4x4.com/index.php?showtopic=13488 Colin www.REEDX.net/landrover Quote Link to comment Share on other sites More sharing options...
Richard Mills Posted October 9, 2008 Share Posted October 9, 2008 Also..... With the voltage at 13 or above going into the battery. Turn on the lights and a few other things. If it drops below 13 then maybe the alternator is either week output or the wiring is going High resistance. Also check the earth connection from battery to engine. On my old Granada, using a clip on ammeter, the alternator gave 145 amps before dropping the volts. At this output it will be squeeking rather loudly, and if the drive belt is not tight enough that will be making much more noise. The biggest problem is most likley to be the earth side, corroded or loose in the crimps. Quote Link to comment Share on other sites More sharing options...
kevinr Posted October 9, 2008 Author Share Posted October 9, 2008 The drive belt is fine on the car, checked and double checked, the whining, I have a feeling is me just hearing things other then what they are..chances are, it's the normal engine noise..or perhaps the gearbox/transfer box during normal operation..I think during my fault finding, I've read too much somewhere that describes the whining being a fault, and now that's all I hear...when I pulled away from my dads house, he said the car sounded fine, So I'm willing to accept that noise as figment of the imagination. What is a fact is that the alternator gets very hot and until recently would smoke...this now appears to have stopped (smoking)...the battery seems to be charging a little, ie, when I take a reading it measures 12.09 volts engine off, when I start it up it drops to 11.99, when I rev the engine, it jumps up to 12.11 volts..so it seems there is marginal activity there. However, My headlights and dashboard lights are dim and the rev counter does not work..even the temp gauge seems faulty, it only climbs a 1/4 way up the scale, where it used to rest at half way once the engine was running at temp...could this be colder weather related?..engine cooling more effeciently? From what I understand, the rev counter failing is a result of the regulator failing as that's where the rev counter connects to..so a simple replacement job..if anywhere locally can get me the damned part!! On looking around the engine area, some of the earth straps look quite muddy, and to be fair, the smell of burning appeared one not so sunny day greenlaning..I just put it down to carp on the engine from all the clay/mud we were trapesing through..my concern now is that I wont get the earth straps off without rounding bolts or snapping studs..I assume if that happens, I can just drill a hole in the chassis and use a self tapper/bolt and nut to reattach an earth strap. My other issue is with hesitation/jerking when I accelerate, I'm not sure if this is related (given it's an electrical fault and V8's seem very much touchy when it comes to electrics) as it all happened at the same time.....smoking/overheating alternator and poor acceleration...all was working fine one minute, and when I started the car up after a 30 minute break the car started to accelerate badly....so..i'm left wih trying to figure this thing out. I've asked the only Landrover autoelectrician in the area for help, but he's about to go on holiday and is not sure he can get to me before he does..so that's about a 2 week wait, and I can't leave the problem that long, and I don't want to risk the travel while the car is basically fubar. Quote Link to comment Share on other sites More sharing options...
jwriyadh Posted October 13, 2008 Share Posted October 13, 2008 From your description the alternator is destroyed. Since you don't seem to be familiar with the elctrical system your best option is to find a local auto electrician and get him to replace it. During the replacement he may find the original cause of the failure. Your fuel injection system will not work properly while the alternator is not charging. Check your engine performance after the alternator is fixed. jw Quote Link to comment Share on other sites More sharing options...
JimAttrill Posted October 14, 2008 Share Posted October 14, 2008 What is a fact is that the alternator gets very hot and until recently would smoke...this now appears to have stopped (smoking)... Well, there's your problem. You have let the smoke out of your alternator and now it doesn't work. You need a new one which is full of new smoke. Quote Link to comment Share on other sites More sharing options...
kevinr Posted October 14, 2008 Author Share Posted October 14, 2008 Well, there's your problem. You have let the smoke out of your alternator and now it doesn't work. You need a new one which is full of new smoke. LMAO..that sounds like something a red indian would say I have a new alternator on the way today..I spoke with a trusted autoelectrician the other day who recommened someone else to me..he was actually able to give me good advice over the phone. Aparently..the garage I originally spoke to said that the alternator would have no bearing on engine performance..the guy on the phone pretty much said what jwriyadh said in relation to engine performance. I've decided to go the whole hog with the repair today, new alternator, new dizzy cap (genuine) new rotor arm (genuine) new HT leads, new plugs, a full service with genuine parts and also the swivel join gaskets as they are leaking..i'll probably do an article for that aswell as I couldn't find one. Quote Link to comment Share on other sites More sharing options...
JimAttrill Posted October 15, 2008 Share Posted October 15, 2008 The LR official method of changine the swivel seals is a waste of time and money for new grease seals etc. The easy way is to disconnect the brake lines and then take the whole outer axle off, including the disc, caliper stub axle and CV joint. Then the swivel seal is easy to change. The whole assembly is a bit heavy but you can support it on a trolley jack to help. 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.