Sam Posted March 9, 2012 Report Share Posted March 9, 2012 Could just about cry about this damn car. So, you probably know, I've had issues with it draining the battery etc. I abandoned it at my folks for a few days, just because I don't have the time. Got it going 2 days ago and decided to drive it home, so I could take it to work and charge it for a full day. Well, I drove the 1 mile home, with the dials going like crazy (at one point I was doing 120mph down the high street apparently!), it cut out, luckily I was basically in a parking space. Jumped it this morning, in the hope I'd have enough luck to get to my office to charge. No chance! Done a 180 in the street, bam, cut out again. Alarm started going crazy. Jumped it again and left it running for 10 minutes in the hope it'd get enough charge in the battery. No such luck, cut out as soon as the cables were off. It's currently abandoned in a MAX 1 hour only space and I've stolen the TT to get to work. Luckily I've had a word with the parking ticket guy whos said I can leave it there. Going to dart off in a minute and buy a new battery, in the hope that the current one is the problem. If not, at least I'll have enough charge to get it to a garage! I love old/classic cars, but I don't have the time of knowledge to deal with the issues. Shall I order a new Micra through work and be done with it?! Link to comment Share on other sites More sharing options...
Quiksilver_TR Posted March 9, 2012 Report Share Posted March 9, 2012 (edited) When you do get it started get a multi-meter and check the voltage across the battery. Should be around 13-14volts when running. If the voltage is less than 12v then you have a charging issue. This could be wiring or alternator related. As for it draining the battery it could ba any number of things. Dodgy earth Stereo connected to permanent live rather than having memory to PL and then the rest on IGN. Battery could just be old and dead. You could also have a short on the alternator or started motor pulling current back (but this tends to cause visual signs like smoke and burnt wiring) When a "battery dies" the alternator doesn't generate enough current to run all the electrics on the car which is why they tend to stall Hope you get it sorted. Edited March 9, 2012 by Quiksilver_TR Link to comment Share on other sites More sharing options...
Sam Posted March 9, 2012 Author Report Share Posted March 9, 2012 When the care is off, battery reads 12.2V, when its running, it reads 11.8v (after being charged) and quite quickly goes down, 0.1v every 2 minutes until it dies on its arse. Read between + on the alternator and the - on the batt is still 11.8v, so I don't think its the cable. Stereo is on switched power. Suppose a earth could have come loose/disconnected, need to find where the points are. It seems as though you point a finger at the alternator, but then say that it could be the battery. Link to comment Share on other sites More sharing options...
Quiksilver_TR Posted March 9, 2012 Report Share Posted March 9, 2012 With a voltage reading of only 11.8v with the engine running id say the alternator isnt working correctly. Should be seeing 13+volts when running. Could measure the voltage directly across the alternator points (both +ve and -ve on the alternator) to see if that is kicking out anywhere near what it should be. If it measures low at the alternator then that definately eliminates wiring Link to comment Share on other sites More sharing options...
Sam Posted March 9, 2012 Author Report Share Posted March 9, 2012 Across the terminals on the alt I get 0.40v, or maybe -0.40v! Trying to get one today, so I can swap it out this weekend. Link to comment Share on other sites More sharing options...
Quiksilver_TR Posted March 9, 2012 Report Share Posted March 9, 2012 (edited) Across the terminals on the alt I get 0.40v, or maybe -0.40v! Trying to get one today, so I can swap it out this weekend. That would appear to be it then. Fingers crossed a new alternator solves it for you. Edited March 9, 2012 by Quiksilver_TR Link to comment Share on other sites More sharing options...
CiSteve Posted March 9, 2012 Report Share Posted March 9, 2012 try stripping the alternator down, look inside and there's a load of copper connections. usually full of corrosion, they act a bit like relays and made a connection under load. but if they're full of crap they wont always connect, VW alts are quite common for this sort of thing Link to comment Share on other sites More sharing options...
Sam Posted March 9, 2012 Author Report Share Posted March 9, 2012 try stripping the alternator down, look inside and there's a load of copper connections. usually full of corrosion, they act a bit like relays and made a connection under load. but if they're full of crap they wont always connect, VW alts are quite common for this sort of thing Or just buy a new one That sounds like too much hassle! Link to comment Share on other sites More sharing options...
CiSteve Posted March 9, 2012 Report Share Posted March 9, 2012 true, but if i bought a new alternator every time one of mine went on my offroader id be living off super noodles! especially at £160 a pop! if you cant get hold of one though, its easy enough to do, takes about half an hour to strip and clean and rebuild, i did my vr6 one when i first got it. Link to comment Share on other sites More sharing options...
simonlpearce Posted March 9, 2012 Report Share Posted March 9, 2012 true, but if i bought a new alternator every time one of mine went on my offroader id be living off super noodles! especially at £160 a pop! Whats wrong with super noodles, they go great in a bit of bread Sam, usually power issues are either battery or alternator, and in this case it very much sounds like alternator. Hope you get it sorted mate, then go find a nice posing spot and stick some piccies up. Link to comment Share on other sites More sharing options...
mit Posted March 9, 2012 Report Share Posted March 9, 2012 This might be a useless comment... but... as long as I've been on this forum you haven't owned an E46 yourself. Perhaps it's time to give up all of these lesser alternatives and get an E46? Link to comment Share on other sites More sharing options...
simonlpearce Posted March 9, 2012 Report Share Posted March 9, 2012 I think i remember a time when Sam had an E46....way back when! Link to comment Share on other sites More sharing options...
Sam Posted March 9, 2012 Author Report Share Posted March 9, 2012 Ah, member 213, of course I've owned a E46, even member 366 remembers those days. The 323Ci SE 1999 machine was owned for about 6 months (quite long for me!). I actually started this site because the only E46 forum I found was E46Fan... no, I won't plug them. So, been talking to a few people at work (engineers, electricians etc), seems it may also be a dodgy earth. I can't get a alternator till Monday, so I've been instructed to take my jump lead from the neg term on the battery to the alternator case and see what voltage I get then. Should be fun! Link to comment Share on other sites More sharing options...
Jay. Posted March 9, 2012 Report Share Posted March 9, 2012 I remember your black coupe Sam! Did you have the subframe tear or somethin? Link to comment Share on other sites More sharing options...
chris Posted March 9, 2012 Report Share Posted March 9, 2012 I remember Sam's E46! Was a while ago Link to comment Share on other sites More sharing options...
Sam Posted March 9, 2012 Author Report Share Posted March 9, 2012 (edited) I remember your black coupe Sam! Did you have the subframe tear or somethin? Ah yea, the black one... Which was silver . Yea, BMW fixed it for me, I got it in just before 10 years old. So it was 3+ years ago now. Right this car is doing my not in! I get drain from the battery when the ignition is on, but engine not. But I even get drain when everything is off! So a short. But the battey doesn't go to 0v ever. I'm going to have to put the TTs battery in mine just to move the damn car! Edited March 9, 2012 by Sam Link to comment Share on other sites More sharing options...
Sam Posted March 20, 2012 Author Report Share Posted March 20, 2012 New alternator fitted, still not charging. Going to try. Pulling fuses tomorrow Link to comment Share on other sites More sharing options...
Stick Posted March 20, 2012 Report Share Posted March 20, 2012 What is the voltage of the battery with nothing happening, just lifting the bonnet and reading ? Should be minimum of 12v. Get the car idling, you should be expecting to see 13.8v or more. Check them reading from the back of the alternator rather than the battery. If you have the correct reading from this then you have something draining the battery pretty rapidly, this can be a dodgy earth, a control unit not fully powering down or an internal short on a system. If your not the cleverist with electrical diag then i would get it booked into a sparky mate. If your handy i would fire up the multi meter and use it to test for drains, if you have a stand alone amp clamp this would be better/easier, Link to comment Share on other sites More sharing options...
HP88 Posted March 20, 2012 Report Share Posted March 20, 2012 Had a similar problem with my Golf last year, the wiring loom for the alternator was damaged and the fuse tray on top of the battery needed replacing. Link to comment Share on other sites More sharing options...
Sam Posted March 21, 2012 Author Report Share Posted March 21, 2012 I have tested from the back of the alternator, also taken a cable from the negative to the alternator body to earth it. Still no go. It's got to be a drain somewhere. Battery holds about 12.4v when car off. When on it goes to 11.8v-ish. That's with all 3 alternators! Link to comment Share on other sites More sharing options...
Quiksilver_TR Posted March 22, 2012 Report Share Posted March 22, 2012 Might be worth checking the exciter voltage circuit Sam. Taken a link from VWVortex http://forums.motive...ead.php?4657363 Given your symptoms, the first thing I would check would be the pre- exciter light itself. It may be helpful to discontinue the term "idiot" light for this bulb, and instead refer to it as a "voltage imbalance indicator", or "pre-exciter" indicator. Bosch calls it a "charge indicator lamp". The warning light is more than an idiot light. It is part of the pre-exciter circuit. If the light bulb is missing or burned-out, the pre-exciter circuit "no workie". It is in series between the battery and the alternator, in otherwords, there is no way current gets around the bulb. Think the light as the pivot of a see-saw. The light goes on whenever the see-saw is not level, that indicates that current is flowing in either direction due to a voltage imbalance. Such an imbalance exists when the ignition key is in the "on" position, but the engine has not been started. Battery voltage exists on one side of the light (12V), but there is no voltage on the other side of the light and the circuit is grounded-out at the alternator housing (B-), after passing through the rotor exciter winding and voltage regulator. The little bit of current that flows through the pre-exciter circuit (little meaning around 2 amps, that is why the wire is not that large), gets the magnetic field established in the ROTOR (spinning part), so the alternator can begin to generate electricity. Now, the alternator puts up a 12V potential at the pre-exciter wire terminal. There is 12v from the battery still on the other side of the exciter light, so the see-saw is balanced and the light goes out!!! Even if the pre-excitor circuit is dead, however, the alternator may be able jump-start itself if it is reved fast enough, and that sounds like your situation. Link to comment Share on other sites More sharing options...
mintimperial Posted March 22, 2012 Report Share Posted March 22, 2012 Sell corradoBuy BM???????PROFIT Link to comment Share on other sites More sharing options...
Sam Posted April 18, 2012 Author Report Share Posted April 18, 2012 (edited) Woah, I've been keeping you boys in the dark about this it seems. Well, last update was bad news, 2 additional alternators purchased and still no joy. Well, good news, its fixed. Kind of. It seems everyone I've spoken to knows about this, but neglected to mention it when I was asking for their help. The excite wire. "Ah yea, of course" they all said. Basically the excite wire gives the alternator 12v to tell the regulator to output 14v back to the battery. Originally my findings where that this secondary cable was purely for the dash warning light. Anyway, I put a massive cable between the battery positive and the excite terminal and I get charge. HURRAAAHHAHAHAH. Well, I decided, rather than keeping the brand new alternator, I'd swap to my old one, turns out it works fine. So I've spend £110 on 2 alternators when mine worked (once it got the 12v supply it needed!). I then decided it was a bit of a challenge to replace the excite cable, it goes all over the place and ends up in the fuse box (not fused though), which is in the drivers footwell, making any work very difficult. Easy peasy, I'll just run as cable from the battery to it, with an inline fuse. Nicked some supplies from work and made the cable up. It worked, but now the cable was draining the battery when the car was off, it'd be flat within 2 hours (properly flat...), due to it being on the battery, it was a constant draw. So, now, around town, I drive without the alternator outputting 14v, so eventually it will not start one day. I'll take it on a longer drive every few days, and that's when I connect the cable up again and get some charge going back into the battery. It seems the best solution is to either find a switched power source under the bonnet or simply replace the cable that is knackered. But, at least I'm driving it about. ...That was until I arrived home after giving it a clean with steam coming out the bonnet. Turns out there is a nick in the coolant hose. The replacement hoses and coolant arrive today. Edited April 18, 2012 by Sam Link to comment Share on other sites More sharing options...
Quiksilver_TR Posted April 18, 2012 Report Share Posted April 18, 2012 Easy fix then. Or put a diode in the excite wire so that current only flows one way?? (not sure if it works that simple though) Link to comment Share on other sites More sharing options...
Sam Posted April 18, 2012 Author Report Share Posted April 18, 2012 Easy fix then. Or put a diode in the excite wire so that current only flows one way?? (not sure if it works that simple though) There is a diode inline too. The cable from battery to excite the correct way. Its not current flowing back from the alternator, so a diode wouldn't help. Link to comment Share on other sites More sharing options...
