Lotus Elan and Lotus Elan Plus 2 Forums

Hi All. I'm a newbie with an S4 Coupe that is in France and has lost it's charging system!

After Day 1 of the Champagne Rally I arrived at the hotel here in Chamouille with strange ignition problems. I've spent the past couple of hours searching this forum and am asking the astounding font of knowledge 'out there' if you can help.

Symptoms:
With ignition switch off, and even with key removed, Ignition light remains ON.
With ignition in run or start position, ignition light remains OFF. Engine starts just fine but ignition light remains OFF, even at low (800rpm) idle.
No decrease in idle rpm when the Full Beam lights are on.
Multimeter indicates no charging voltage (which should be around 14v) when engine revs increase.
I have check the alternator belt tension.

IMHO:
Ignition light bulb is fine (it illuminates!)
Ignition light is not providing power for initial excitation of the alternator windings, hence the alternator is not charging the battery.
Before assuming that the alternator (Lucas) diodes have died, I'm tempted to dismantle and clean the ignition switch,which is on the dash not the column (excellent advice on how to to this on the Forum).
It'll soon be Sunday and most of France will be closed. I'm resigned to not driving tomorrows Rally and spending the day working on the car. We're in a lovely hotel!

The car has been recently rewired, with 8 fuses, 3 relays and the alternator. Nothing appears to have fallen off/ been displaced - but it is now dark! Battery is now isolated to preserve whatever charge remains. I'll start work tomorrow.

Can you help? We need to get back to the UK! Any suggestions appreciated.

Thanks, Don

Dear Don

I am afraid that my money is on the Alternator, sorry I cannot be more helpful.

Regards

John

Salut Don

Check your spade connections to the alternator - remake them if you can to make sure there is a circuit. A mate lost hours during a rally - visual inspection looked OK but the stripped wire was held by the plastic shroud so no circuit.

I hope it's something simple like that.

@+

Vernon

My money is also on the alternator being cooked.

Here is my theory!

The alternator is connected to the solenoid so has a permanent live.
When you switch the switch off there is no supply so the ignition is getting an earth through the other components (coil etc) connected to the terminal. and the lamp lights. When you switch it on the terminal is connected to the battery supply so there is no potential difference and it extinguishes.

If it was something else it would still light when you switch on the ignition since that is what it is supposed to do.

With everything off disconnect the alternator from the solenoid - if the light goes out that is where the rogue supply is coming from... and it shouldn't.

I would check all the earth points, BTW.

Regarding your return to the UK. I had also alternator problems, in France also, on my way from Spain to Switzerland. Solution: buy a new battery, if you drive during the day, the battery lasts for about 400 to 500 km.
Then two options: go to a hotel, then you have to buy also a charger for recharging or buy a second battery and drive the next 400 to 500km. Don't drive at night, bad idea ! If your battery dies, you wont have battery for the emergeny indicators !

check the fan belt if its ok buy a volt meter and or buy a new alternator from nissan denso dealer

Also the ignition light must turn on and be put by the voltage flow to start to charge so you may have a miss wiring problem at the switch Or the field wire I broken or loose On the charge unit connector ....l

Thanks for all the helpful advice and tips. I'm pretty certain that it is the alternator - a fellow, very knowledgeable, entrant (in a pre-war Morris 8!) gave this diagnosis as soon as I described the ignition light remaining on with the key removed.

Alternator is now removed and I'll be using my schoolboy french to find a motor factor nearby and buy the correct alternator (Lucas).

I'll probably need to move the existing pulley to the new alternator and recall that removing the big nut that holds the pulley on is a ba**ard without air tools! Hopefully I'll find a local garage with air tools...

Thanks once again for all your help.

Don

gherlt wrote:I would check all the earth points, BTW.

Regarding your return to the UK. I had also alternator problems, in France also, on my way from Spain to Switzerland. Solution: buy a new battery, if you drive during the day, the battery lasts for about 400 to 500 km.
Then two options: go to a hotel, then you have to buy also a charger for recharging or buy a second battery and drive the next 400 to 500km. Don't drive at night, bad idea ! If your battery dies, you wont have battery for the emergeny indicators !

Good grief, no. They must be able to fix or replace a standard alternator in France.

The usual one on an Elan is a Lucas ACR 17

Out of pure intellectual interest does anyone have a theory why the alternator light would come on with the ignition off?

The alternator internal circuit is shown in this thread:
lotus-electrical-f38/ignition-light-not-t28756.html?hilit=alternator%20circuit

At this message:
lotus-electrical-f38/ignition-light-not-t28756.html#p190798




And the simple answer seems to be that the light should NOT come on if the harness is wired correctly because it looks as if the wire to the bulb on the other side from the alternation is wired to the ignition switch and would have no 12v feed to it. Even the permanently connected 12v to the + terminal shown, would not have a path via blown diodes back through the ign light to the switch.

However the diagram does not show the full story because, I guess that that terminal in the ignition switch also feeds the power to the ignition coil, so if the diodes are blown, when the distributor contact breaker is closed (or if you have electronic ignition) current can pass from the + terminal on the alternator, through blown diodes, through the ign bulb and then down to earth through the ign coil and the contact breaker.

twincamman wrote:Also the ignition light must turn on and be put by the voltage flow to start to charge so you may have a miss wiring problem at the switch Or the field wire I broken or loose On the charge unit connector ....l

Although the current flow through the warning light will help the job along, an alternator will self excite using the residual magnetism in the rotor to pick itself up by its own bootstraps. Without a warning light, you might need to give the throttle a good blip to get the alternator to self sustain, but it does not need a warning light connected to get going.
I have an ancient Perkins diesel generator that has a Lucas 17ACR alternator fitted to keep the starting battery topped up. It has no ignition warning light, but the alternator manages to get going just fine all on its own when the old diesel clonks into life.

billwill wrote:The alternator internal circuit is shown in this thread:
lotus-electrical-f38/ignition-light-not-t28756.html?hilit=alternator%20circuit

At this message:
lotus-electrical-f38/ignition-light-not-t28756.html#p190798




And the simple answer seems to be that the light should NOT come on if the harness is wired correctly because it looks as if the wire to the bulb on the other side from the alternation is wired to the ignition switch and would have no 12v feed to it. Even the permanently connected 12v to the + terminal shown, would not have a path via blown diodes back through the ign light to the switch.

However the diagram does not show the full story because, I guess that that terminal in the ignition switch also feeds the power to the ignition coil, so if the diodes are blown, when the distributor contact breaker is closed (or if you have electronic ignition) current can pass from the + terminal on the alternator, through blown diodes, through the ign bulb and then down to earth through the ign coil and the contact breaker.

Bill's analysis looks correct, either the diodes have blown or there is a short in the wiring harness or alternator plug that is connecting the IND connection to battery +ve. Engines have a habit of stopping in the same place, usually at the start of a compression stroke - this is the reason the ring gear wears in one spot, the starter always hits the same part of the gear as it engages. At the start of a compression stroke the points will be closed, so although you would have expected Bill's analysis to lead to the ignition warning light sometimes being on and sometimes off when the engine stopped depending on whether the points were open or closed, it is most likely that they will be closed and the light on.

Jentwistle3 wrote:Out of pure intellectual interest does anyone have a theory why the alternator light would come on with the ignition off?

Andy8421 wrote:Bill's analysis looks correct,

I don't know why I bother Third response above and a method of testing it!

Good grief, no. They must be able to fix or replace a standard alternator in France.

The usual one on an Elan is a Lucas ACR 17

Dont count on it

Replace, yes, eventually but at a price you wont believe probably with a ?300 surcharge on the old unit which you will never get refunded.

Repair, not on your nelly no repair parts are available, I was faced with a similar dilemma when my ignition light came on returning to France from the UK and that on a modern everyday vehicle not a classic as it was a diesel I continued my journey, a reconditioned alternator here was ?300 plus between ?150 and ?200 deposit on the old one, it would cost another ?30 to return mine and they always say that they are unserviceable I would also have waited at least a week for the delivery if I was lucky.

Brand new one delivered next day from the UK ?100, no surcharge or return of old unit, replacement regulator and brushes (my problem) ?13 plus postage (envelope) arrived in two days.

If you are still struggling my advice would be to disconnect the alternator plug(s) from the rear and drive on a charged battery, if its a failed diode it will rapidly discharge the battery while you are driving or at standstill.

Good luck, if you get stuck in Northern France and need assistance PM me.