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> battery connection screw up
dt4
post Jan 12 2020, 09:57 AM
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I have had the battery off the car whilst stripping paint and priming etc.... but thought it would be good to turn the engine over and run it for a while to keep things in good health etc.....
I had the battery on the bench to charge it and then put it back in the car but very stupidly put the negative lead to positive terminal and positive lead to negative terminal.
I didnt turn the key as I was checking other things when I realised what I had done.
I noticed that there was a smell of smoke coming from the alternator area and the tin on top of the engine in that area was warm so suspect there is a connector to the alternator under there?

I put the terminals on the right way around and tried to start the engine but it appeared the battery had drained?

I recharged the battery overnight but wouldnt start, again the battery seemed low on charge
Apart from seemingly screwing the battery, is there other damage likely to have occured

cheers
David
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Superhawk996
post Jan 12 2020, 12:04 PM
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(IMG:style_emoticons/default/sad.gif)

There is almost certainly other serious damage if you smelled smoke.

There is no simple answer. If you're not experienced at electrical troubleshooting or lacking for patience I would recommend that it go to an electrical specialty shop.

You don't mention if you have original fuel injection of if the vehicle has been switched to Carbs. At this point having Carbs would work in your favor since there is a possibility that the fuel injection ECU (amonst other things) just got fried.

If you have a schematic, patience, and some experience with electrical items, you'll just have to start tracing wires, checking for blown fuses, looking for blown relays, searching for burned wires, etc.
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wndsrfr
post Jan 12 2020, 12:32 PM
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QUOTE(dt4 @ Jan 12 2020, 07:57 AM) *

I have had the battery off the car whilst stripping paint and priming etc.... but thought it would be good to turn the engine over and run it for a while to keep things in good health etc.....
I had the battery on the bench to charge it and then put it back in the car but very stupidly put the negative lead to positive terminal and positive lead to negative terminal.
I didnt turn the key as I was checking other things when I realised what I had done.
I noticed that there was a smell of smoke coming from the alternator area and the tin on top of the engine in that area was warm so suspect there is a connector to the alternator under there?

I put the terminals on the right way around and tried to start the engine but it appeared the battery had drained?

I recharged the battery overnight but wouldnt start, again the battery seemed low on charge
Apart from seemingly screwing the battery, is there other damage likely to have occured

cheers
David

I've been there, done that. It kills diodes and possibly more in the alternator... likely have to replace it... easy to do on a T4, PITA on my /6....
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dt4
post Jan 12 2020, 12:42 PM
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I'll start with a new battery and replacement alternator (when I find one) and take it from there
thanks for the replies
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Mark Henry
post Jan 12 2020, 01:50 PM
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The radio is likely toast but most else on the dash end is OK I'd think.

I have OCD triple checking, then checking again when it comes to connecting batteries. Always the ground is the first off and last on connections.
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dt4
post Jan 12 2020, 02:07 PM
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Is it safe to put a new battery on the car and try it?
If the alternator is toast, what effect would trying to start it have?
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Superhawk996
post Jan 12 2020, 02:32 PM
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QUOTE(dt4 @ Jan 12 2020, 03:07 PM) *

Is it safe to put a new battery on the car and try it?
If the alternator is toast, what effect would trying to start it have?


I would not start by installing a new battery and hoping for best given that you smelled smoke.

You likely have shorted wiring now either from melting and possibly from diodes. When diodes fail they usually go open but I wouldn't risk it.

At least start by using an Digtital Multi Meter to see if the battery + is shorted to ground.

After that I wouldn't even consider attaching the battery until you've inspected all the engine harness wiring starting with the alternator and the ignition coil.
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SirAndy
post Jan 12 2020, 03:17 PM
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QUOTE(Superhawk996 @ Jan 12 2020, 12:32 PM) *
I would not start by installing a new battery and hoping for best given that you smelled smoke.

You likely have shorted wiring now either from melting and possibly from diodes. When diodes fail they usually go open but I wouldn't risk it.

At least start by using an Digtital Multi Meter to see if the battery + is shorted to ground.

After that I wouldn't even consider attaching the battery until you've inspected all the engine harness wiring starting with the alternator and the ignition coil.

(IMG:style_emoticons/default/agree.gif)

Don't put a battery back in there until you tested all wires ...
(IMG:style_emoticons/default/popcorn[1].gif)
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SirAndy
post Jan 12 2020, 03:20 PM
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QUOTE(SirAndy @ Jan 12 2020, 01:17 PM) *
Don't put a battery back in there until you tested all wires ...
(IMG:style_emoticons/default/popcorn[1].gif)


You don't want to run current through something like this:

(IMG:http://www.914world.com/bbs2/uploads/post-179-1202691212_thumb.jpg)

(IMG:http://www.914world.com/bbs2/uploads/post-179-1202691244_thumb.jpg)

(IMG:http://www.914world.com/bbs2/uploads/post-179-1202691265_thumb.jpg)
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dt4
post Jan 13 2020, 01:25 AM
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@SirAndy @Superhawk96
Thanks for the pointers guys, I will heed your advice
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Breaker
post Jan 13 2020, 03:57 AM
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Just one additional thought:

IF the alternator is new, and IF has never been used since it was installed, then it could be an issue with the + threaded stud touching the alternator tin. It's often too long, and this would short regardless of polarity.
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Chi-town
post Jan 13 2020, 10:41 AM
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Do not install the new battery. Pull the alternator and check for damaged insulation on the primary wire.
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914fahrer
post Jan 13 2020, 11:32 AM
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I think You shot the diodes of the altenator.They resist this only a short time. (IMG:style_emoticons/default/sad.gif)
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dt4
post Jan 13 2020, 02:48 PM
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QUOTE(Chi-town @ Jan 13 2020, 04:41 PM) *

Do not install the new battery. Pull the alternator and check for damaged insulation on the primary wire.


will do Dylan, things were going so well !!

(IMG:style_emoticons/default/thumb3d.gif)
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dt4
post Jan 13 2020, 02:49 PM
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QUOTE(914fahrer @ Jan 13 2020, 05:32 PM) *

I think You shot the diodes of the altenator.They resist this only a short time. (IMG:style_emoticons/default/sad.gif)


I have found some one close by that repairs alternators so I will get it over to him
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Chi-town
post Jan 13 2020, 06:47 PM
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Ok, if you need an alternator or harness let me know and we'll get one shipped.
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KELTY360
post Jan 13 2020, 08:13 PM
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This is a great learning opportunity to get to know your multimeter. Spend time learning to test electrical functions. You’ll be better prepared the next time you let the smoke escape from the wires.
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DickSteinkamp
post Jan 13 2020, 10:13 PM
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Electricity is somewhat of a mystery to me so bear with me.

I don't understand how switching the + and - leads can cause a dead short and burn up wiring. I can understand how polarity sensitive devices (like a diode) might be harmed but why wiring?

Also, there is so very little that gets power with the key in the off position. How would the radio (for example) be damaged?
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bbrock
post Jan 13 2020, 10:26 PM
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QUOTE(DickSteinkamp @ Jan 13 2020, 09:13 PM) *

Electricity is somewhat of a mystery to me so bear with me.

I don't understand how switching the + and - leads can cause a dead short and burn up wiring. I can understand how polarity sensitive devices (like a diode) might be harmed but why wiring?

Also, there is so very little that gets power with the key in the off position. How would the radio (for example) be damaged?


The way I see it, any circuit that is switched and the switch was off when the battery was connected backward should be fine. Any circuit that is always energized is subject to damage. Modern radios often have a switched and unswitched circuit and of course, any radio can be wired either switched or not.
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dt4
post Jan 14 2020, 02:54 AM
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QUOTE(Chi-town @ Jan 14 2020, 12:47 AM) *

Ok, if you need an alternator or harness let me know and we'll get one shipped.

You are a diamond geezer (as they say in the South)
thanks Dylan, let me see how it tests out

cheers
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