Lotus Elan

Battery failure ?

PostPost by: steve.thomas » Sat Oct 30, 2010 5:57 pm

Hello everyone,
I'm hoping someone can point me in the right direction concerning a strange electrical fault just developed on my Plus 2 (surely not I hear you say !).

The problem is just a click from the solenoid when trying to start the engine, and then no electrics whatsoever - not even the interior lights. Wait for a few minutes and power returns, only to repeat the same sequence. The battery terminals and battery earth are clean and tight, as are the connections on the solenoid. What really puzzles me is that when there seems to be no power, I've tried jumping across the solenoid with a screwdriver and get nothing, not even a spark. Even more strange is if I rock the car very gently, power returns (temporarily). Is this a symptom of battery failure and the rocking is just swirling the battery acid around and maybe making some internal connection? As you may gather I'm no electrician, so any suggestions gratefully recieved.
Steve
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PostPost by: Frank Howard » Sat Oct 30, 2010 6:25 pm

Steve,

I think your battery is done. Try substituting a battery from another car. Good luck.
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PostPost by: curly type 26 » Sat Oct 30, 2010 7:53 pm

just a thought try earth connection on left front upright in engine bay.good luck curly :D
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PostPost by: hartley hare » Sat Oct 30, 2010 11:06 pm

hi there
it does sound like a battery problem...
quick test is put headlamps on do they go out when cranking?
if so its battery, even if connections look good..
also when you say rocking car,are you talking about in gear and checking for jammed starter?
if so this could also give symptoms of no sparking at solenoid...
otherwise its check all main connections,and previous suggestions,
just my view...
all the best..

keep us posted...
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PostPost by: steve.thomas » Sun Oct 31, 2010 12:06 am

Thanks for the replies so far. I'll check out the engine earth strap tomorrow. I can't check the headlights as the engine doesn't crank - just a click from the solenoid and then everything is dead. Regarding the rocking, i didn't actually mean in gear to free a jammed starter, i found by chance that just bouncing the rear end slightly (in neutral) restored the electrics as if there is a very loose connection somewhere, or could it be the movement of the battery itself?
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PostPost by: rgh0 » Sun Oct 31, 2010 12:56 am

Have a look at the earth connection to the chassis at the rear. bouncing the car may be flexing the chassis and helping this connection to conduct if its loose or corroded.

cheers
Rohan
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PostPost by: bob_rich » Sun Oct 31, 2010 8:53 am

Hi Steve

There is another possibility as I had very similar symptoms on my +2. It turned out to be a short circuit on the insulator that feeds the +12V through the starter motor casing. In my case it had a cheep plastic bush to line the hole in the case to prevent the 12V feed shorting to the case. This had melted and so when the solenoid operated the battery was shorted to earth. Just as you found I also noticed that after the canning the battery had, it recovered slowly ( over a minute or so)back to 12V. The PO had changed the starter motor and the solenoid and the old starter motor ( that came in a box of bits with the car) had the same problem. In my case after several attempts to start B4 I found the fault, the high current damaged the solenoid switched terminal also the wiring from the battery to the starter motor was very hot--much hotter than usual after engine cranking. I did manage to drill out the rivets and repair the solenoid. I also made up a better feedthrough using small pieces of epoxy glass insulating board so that I could tighten up the 12V feed to the motor really tight for a good low loss connection.

I think I would check the starter motor out as a shorted battery can deliver a lot of power and this goes in the wiring and the solenoid switched terminal as well as canning the battery.

hope this helps best of luck

Bob
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PostPost by: Craig Elliott » Sun Oct 31, 2010 9:41 am

Adding to the list of stuff... I suspect it could also be a fault in the starter motor itself. C
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PostPost by: steve.thomas » Sun Oct 31, 2010 1:15 pm

Solved it !
Thanks to all those who replied. The rain has just eased just sufficiently for me to get out at the car and as Rohan suggested it was simply the battery earth on the chassis being only finger tight. I'm disappointed in not finding this earler as I had remembered this being a problem area from previous Elans and I had cleaned and tightened the connection from within the boot as a precaution a few months ago. What I had forgotton or maybe never realized is that the bolt is threaded into the bobbin in the body, so tightening the nut does nothing for the connection to the chassis. I was tempted to drill the thread out and just bolt right thru, but that means lowering the exhaust to get the bolt out so I'll leave that for another time.
The car started easily 10 out of 10 attempts, so I guess that's it !
Thanks again.
Steve
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PostPost by: alexblack13 » Mon Nov 01, 2010 2:14 pm

I know it's been done to death this but, The earth position is without doubt one of the worst places for it. I Moved it! I
put it onto the plate which stretches between the rear suspension uprights. Take out the body to chassis through mounting bolts (both sides) and fit a new ring connector, (soldered on), to your cable, before bolting it through the plate direct onto the chassis. No need to tell you to clean off the paint under the ring terminal is there? Then take a link with the same (welding cable) across to the other side too and bolt it on there also. Use that plate as a large earth ''Bus Bar''. Bolt, or even better solder and bolt on some large male spades. More earthing points than you can shake a stick at... I then ran two good thick blacks along to the bottom dash to chassis mounts and all my panel is earthed through that. As well as the loom earths that is. Belts and braces... :wink:

So far so good..Whilst you are at it throw away those bullet push in con's too..Solder the buggers up and heat-shrink insulate them. My loom (apart from the plugs on the dash loom) is all soldered up,shrunk wrapped and then taped with the same loom tape as the manufacturer (Auto sparks) used. It looks like a solid 1 PC item. (NO push in con's to rust/corrode/& give up on a nice dark wet night...

Happy days... Wee Bob (Name came from silver shilling found in the ashtray) is hibernating now. New 5 speed going in soon.

Have fun guys... :wink:

Al' .... 8)
Alex Black.
Now Sprintless!!
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PostPost by: gerrym » Mon Nov 01, 2010 9:24 pm

Rear Earth as Alex says is just about the worst design possible.

I have a stud welded to the chassis which protrudes up into the body. The welded connection (painted of course) ensures the best possible electrical connection. The cable lug makes a connection with a serrated washer on to the stud, and the whole lot is out of the weather inside the boot with access only required on one side of the panel to tighten and/or clean.

Regards
Gerry
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