Lotus Elan

Electrical problem

PostPost by: chrishewett » Mon Sep 19, 2005 6:54 am

I took the +2 for it's first long run yesterday to Goodwood and the trip highlighted a few mysterious problems.
Before giong I had replaced all the fuses which were old and mostly the wrong type. I then found that the headlights and stoplights were not working. With a bit of fiddling I got them going. I also found a wire that was live going to the alternator was loose. Having soldered it up I set off. I noticed that the battery dial which is normally at 13volts when running had gone to the minimum. The other problem was the tacho bouncing about and the panel lights flashing on and off. These were ok when accelerating but when at steady revs or on the overrun the tach went wild.
I decided to press on and had a good day. When I left to return home all seemed to be back to normal but I noticed that when the window motor was operated the battery dial went down and the tacho bounced.
The battery is good and reads nearly 13volts which goes to 14.5 when charging.
I obviously have an electrical problem, not my best subject!
Can anyone suggest where I should start with this?
Chris
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PostPost by: types26/36 » Mon Sep 19, 2005 7:41 am

Probably not to much help but it sounds like an earthing problem, couldn't be specific but I would start by checking as many earths as you can,even running new earths to rev counter, gauges etc.
Brian.
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PostPost by: Hamish Coutts » Mon Sep 19, 2005 7:56 am

Chris,

I think Brian's on the button. Check in particular the earth strap for the engine, the one that bridges the engine mount, (may cure the non charging problem) and the dash earths. (there's usually a bunch of these attached to the chassis mounting bolt behind the dash board and on top of the transmission tunnel)

If you have the time check all earths as over time they become dusty and oxidised and can go high resistance.

Regards,

Hamish.
"One day I'll finish the restoration - honest, darling, just a few more years....."
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PostPost by: elanman3 » Mon Sep 19, 2005 12:01 pm

I had a similar problem with dash lights and dials not working or fading way. The cause was the earth point at the back of the dash. When the replacement chassis was fitted, whoever had done it hadn't bothered to take the body back off to drill and tap the chassis.
You may want to take a small inspection mirror and look down into the bolt hole to see if there are threads for the bolt to tighten on. I ended up running a separate earth cable back into the boot. Not the correct solution but it worked.

Colin
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PostPost by: cliveyboy » Mon Sep 19, 2005 3:16 pm

Chris
Also check the condition/tension of the alternater belt, it could be part of the problem.
I have just retensioned mine and eliminated a few of the syptoms you described.
Clive
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PostPost by: chrishewett » Mon Sep 19, 2005 5:04 pm

Thanks to all. You have given me something to start on. After everything I have done on the car I realise that I have neglected the electrics. I will start with the earths and keep you posted.
Chris
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PostPost by: freddy22112211 » Mon Sep 19, 2005 8:12 pm

Had a real funny recently - the horn wouldn't work - after a lot of searching for the lost volts - about 5 volts were missing somewhere - it turned out that the old glass fuse had a dud connection at one end - resoldered it (didn't have any new ones) and it works fine!
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PostPost by: chrishewett » Tue Oct 11, 2005 6:05 pm

Just to update you all.
I finally managed to get the bolts out that have the earths mentioned by Hamish. Someone had used a bolt with a nut under the chassis which was a job and a half to get at! I used a new bolt and nut with everything cleaned up. I also ran another earth from the same bolt underneath to a starter motor bolt to make sure. The good news is that panel lights, battery indicator and tacho are now working as they should. Even better news is that the headlights are brighter and the windows go up and down quicker!
Thanks for all the suggestions.
Chris
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