jimbob907

Ok so I’m going to try and make a full post about my fault on my lotus Evora S 2011 and how I fixed it, hopefully this will aid someone who has a similar problem in the future and might want a bit of guidance. 1) firstly the symptom I was experiencing- A: full dash shutdown when I had a demand for electricity after 5 mins (so fans on or windscreen wipers) B: engine wouldn’t start even after a drive with any electrical demand C: slight metal burning smell D: battery never fully charged from driving sat about 11.8-12V but would charge up to 12.8V off a home charger. 2) how I diagnosed the fault- A: using a Voltmeter or a battery tester I measured the voltage across the battery with engine not running, read 12.8V after a full charge at home. B: start engine, voltage does not drop significantly, shows battery load is ok. This is a good point to test your earth too. Test the voltage drop between the engine and the negative terminal should be 0V or very close. You could do resistance test at this point too if you prefer. C : with engine running measure voltage across battery. Mine read a low 12.2V I would expect to see above 14V. This shows that the battery is not receiving enough power to keep full charge, D : with engine running, operate cabin fans and headlamps, mine read a very low 11.2 volts and was dropping. On a working system I would expect to see it maintain at above 14V E: take out rear seats and remove the panel to get access to the alternator. Be very careful with the bolts here, you want to use a very good Allen key so that you don’t slip the drive when turning the bolts. With engine running do a volt test between the B+ post on the alternator and a good Earth (we have already checked the engine so just use a few bits of exposed metal on the engine in front of you) mine continued to read a low voltage <12V I would want to see 14+ on a good system. F: it looks fairly conclusive that my charging system is at fault. I took off the plug with ignition on and engine off. I done a Volt test here between all 3 pins and an Earth. I would expect to see battery Voltage at this point and I did which was a relief because that would be a wiring problem. Also a good idea to check the contact points for this plug on both the plug and the alternator side at this point, if dirty or corroded it could interfere with your charging system. G: I put the plug back on and tested the alternator voltage output again in a hope that disturbing this plug may have made the difference. For me it did not. I’m 100% happy that the alternator is at fault. 3) replacing the alternator. This is a very easy job made extremely difficult by the size and location of the engine. Thank god they put the panel in the cabin bulkhead otherwise this would be impossible. A: you’re going to need the following tools as well as your standard ones. A long reach 14mm spanner A 4mm Allen key or I used a cable tie to hold the tensioner in place long extension bars and universal joints (I used impact ones as they’re not so wobbly) a large breaker bar I used a 2 foot long one sockets with 6 flats on. Mainly because how tight the bolts are. Also, spare bolts were not provided in with the replacement alternator so you dont want to damage them coming out. B: I used a 4 post lift but I cannot see any reason why this couldn’t be done on Jack stands. It will add a slight access disadvantage but still doable in my opinion. -Jack car and remove right hand wheel and wheel liner for access -remove aft under tray for access -remove rear seats and remove bulkhead panel for access C : remove battery connection, remove lead to B+ post, remove p clip on alternator. Remove bolt behind the alternator (bottom right as you look at it) D : use long 14mm spanner to take tension off of belt. Accessed from underneath. I couldn’t find the hole to put the Allen key in to hold the tensioner. Instead I used a cable tie to hold the spanner in place. (Obviously this comes with it’s own perils so beware, however I had no problems) leave the belt over the pulleys until it’s either in the way or you’re ready for the alternator to come out E : remove top bolt from alternator. This was on really really tight and I found it had to be undone from the wheel arch using a big breaker bar and universal joints. There is an hose just in front of it but this can be pushed down to access the bolt. Even then it was incredibly tight, once it was cracked off access from the bulkhead to remove then reinstall was easiest. I used a flexible ratchet ring spanner. F: remove lower bolt. Access via wheel arch. There’s a convenient hole to access this. Again it was tight as hell. G: That should be the last bolt. Slip the belt off trying not to remove it from any other pulleys. Use a pry bar to push it out from the engine and hey presto it’s out. putting in the new one is obviously done in reverse, getting it back in the hole is tough work. I found if you remove the plug from the air conditioning pump you get pretty good access to the lower bolt. Also if you put them all in loose first you will be able to get them all in. the whole thing took me about 5 hours start to finish. it wasn’t an easy job but it fixed the fault. Now the battery is charging at a full 14.5V. Good luck anyone looking to do this at home and let me know if I forgot anything.

Warning lamps only work if the dash has power. Below 10V for 10 seconds will give you an engine warning lamp. I had this eventuality which stuck for a few engine start after. new alternator on order but it’s flying in from Berlin so it takes a week to arrive. All being well I will have fitted it this time next week.

Thankyou all for your advice on the battery, I have tested the battery and I’m happy that it is in good condition. Despite this I have changed it anyway and sure enough it’s the same problem. The alternator doesn’t maintain voltage and the battery discharges itself until systems start dropping off. Engine produces probably 12.4 volts which isn’t enough to charge it but you can drive about without fault but when you put lights/windscreen wipers/blowers on it drains really quick. Yesterday it rained heavily so all these were on and the dash cut out because it was too much load and couldn’t top it up quick enough. So I’m back to the alternator. Been able to order a new one for £188 using part number 27060-31082 and I’m waiting for that to arrive. There is a recondition kit available for $48 but that doesn’t include a rectifier and I will have to wait for shipping from the states. Meanwhile I’ve tested the plug that controls it and im getting good voltage to each pin so that’s the wiring ruled out hopefully. access actually looks pretty good as you can go in via the Cabin/engine bay bulkhead, there’s a few bits you can take out to make it easy on yourself and you need the right rear wheel off to get the tension off the belt so Im feeling pretty positive about this. I will report when I’ve done the job. And hopefully the next person to ask this will have a better point of reference to go off.

Did you make any progress with this marbles? I’ve had this accelerating into a dip on a road, I suspect a bad earth somewhere probably main engine one but wanted to check what fixed yours.

Thanks Bibs, I will give that a go and report back. Cheers

Good morning, and thanks for Having me as a forum member and for reading this thread. Recently brought my Evora S (2010) privately. Drove well the first day, second day I sat in it for a few mins before starting (fans and stereo running)by the time I come to switch on battery is flat. I’m thinking the battery must have dreadful capacity. Sure enough 11.2V so I put it on charge over night must remember to start up straight away in future till I get a new battery. Next day started fine as you would expect battery was 12.7V. But when running the voltage dropped down to 12.1V at idle and would increase to 12.5V at revs (proportional to the rev speed). I tested again B+ to earth with same result. After a drive it only reads 12V which I think the system can hold it there ok, but obviously well below the 14V it should be at. This to me seems that the voltage regulation system is dead. Has anyone had any experience in this fault? Is the voltage regulator difficult to get to is it integrated in the alternator? Is the alternator difficult to change (I’ve read conflicting answers in your forum but no real advise) things I’ve tried- testing from battery, testing from the alternator removing the exciter/battery capacity plug and refitting. TIA, ben