Dodgeboy95's MR2

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Mr. CoolFiat

Mr. CoolFiat

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dodgeboy95
hi i just need anyones help right now.
i bought i new battery for my 87 toyota mr2 and forgot which side the + and - are supposed to go.So it made sparks and none of the lights or anything is turning on.

could anyone let me know if it could be the electrical system is blown.
i need serious advise
thanks
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He seriously needs help with his car. He asked me to ask for help on here. But he is offline right now and can't spread the word.
 
Well starting with the basics, here's your average car battery:

627px-Photo-CarBattery.jpg


As far as I'm aware, the positive terminal will always be on the right hand side when the terminals are at the front (like in the image), and the negative on the left. It should be marked anyway.

The MR2 will be negative earth, which means when disconnecting the battery, the negative terminal should be disconnected first (the earth strap), followed by the positive. When re-connecting, the positive should be connected first, followed by the negative. Never bridge the terminals unless you want a wrench melted to your hand and a potential explosion.

From the sounds of it your friend accidentally earthed the battery. It's hard to tell whether it's done any damage unless the battery is visibly damaged, but his best bet is to disconnect it all again and reconnect it in the correct manner, and see if it works then. If it doesn't, then further diagnosis will be needed.

I'd add that if the battery is hot to the touch too, he's probably damaged it and should get another.
 
homeforsummer
As far as I'm aware, the positive terminal will always be on the right hand side when the terminals are at the front (like in the image), and the negative on the left. It should be marked anyway.
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Incorrect I'm afraid, you can choose which side you want your posts on when you buy the battery. You will get sparks no matter what order you put them on as there is usually some small load on the battery for small things like the radio memory, clock etc. However if they have been put on the wrong way... That's a different kettle of fish as major damage could have been done and that's why I recommend seeing an auto sparky because it's a pretty simple thing to get wrong so anyone that may have should just leave it to people who actually know what they are doing before they do major damage.
 
Punknoodle
Incorrect I'm afraid, you can choose which side you want your posts on when you buy the battery. You will get sparks no matter what order you put them on as there is usually some small load on the battery for small things like the radio memory, clock etc. However if they have been put on the wrong way... That's a different kettle of fish as major damage could have been done and that's why I recommend seeing an auto sparky because it's a pretty simple thing to get wrong so anyone that may have should just leave it to people who actually know what they are doing before they do major damage.
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Wouldn't a fuse blow or something?
 
Yes there is a fuse but it may not be as simple as that depending on what is in the car, if you tried to start it etc, you may have fried a number of things.. I believe when it comes down to thing like this if you've already goosed it then it's probably best left to a professional.

Fuses don't provide protection for everything.
 
The battery in my MR2 has the positive terminal on the right. Its not an OEM replacement battery though, its bigger.
 
Allright, I will tell him this ASAP. Thank you for helping anyways guys!
 
Punknoodle
Incorrect I'm afraid, you can choose which side you want your posts on when you buy the battery. You will get sparks no matter what order you put them on as there is usually some small load on the battery for small things like the radio memory, clock etc.
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I've never had sparks when disconnecting and connecting batteries. If you're getting sparks you're almost certainly disconnecting/connecting the terminals in the wrong order.

I wasn't aware that you could choose which side the terminals are on, but even so it should be marked on the cover, and even if it isn't then you should have a fairly good idea which side they were on if you asked for it a particular way yourself.
 
Once you connect one terminal you create a potential difference between the opposite terminal and lead, no matter whether it be the positive or negative, if there is a load connected to the battery. In creating the circuit (hooking the lead up) if the load draws enough current it's going to create small sparks, no matter if it's the positive or negative lead you connect.

My multimeter on Ohms scale will create sparks when touching the leads together, and that is only to drive a little beeper. You should see the sparks my Megger Insulation tester makes :)

These are small sparks mind, if you are getting large sparks (ie the kind of sparks you get if the solenoid on the starter is stuck and you connect the battery up) then something isn't right.

Long story short, if you can't even tell which lead is the positive and which is the negative, LEAVE IT ALONE.

I've gone in to fix enough people's wiring mistakes that damage expensive gear that could have been avoided if a professional such as myself had been contacted in the first place.
 
i dont know if all car battery's have this but usually the - lead is a bit smaller then the +,

and yes car battery's can have + - or - +
 
homeforsummer
I've never had sparks when disconnecting and connecting batteries. If you're getting sparks you're almost certainly disconnecting/connecting the terminals in the wrong order.

I wasn't aware that you could choose which side the terminals are on, but even so it should be marked on the cover, and even if it isn't then you should have a fairly good idea which side they were on if you asked for it a particular way yourself.
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Punknoodle
Once you connect one terminal you create a potential difference between the opposite terminal and lead, no matter whether it be the positive or negative, if there is a load connected to the battery. In creating the circuit (hooking the lead up) if the load draws enough current it's going to create small sparks, no matter if it's the positive or negative lead you connect.

My multimeter on Ohms scale will create sparks when touching the leads together, and that is only to drive a little beeper. You should see the sparks my Megger Insulation tester makes :)

These are small sparks mind, if you are getting large sparks (ie the kind of sparks you get if the solenoid on the starter is stuck and you connect the battery up) then something isn't right.

Long story short, if you can't even tell which lead is the positive and which is the negative, LEAVE IT ALONE.

I've gone in to fix enough people's wiring mistakes that damage expensive gear that could have been avoided if a professional such as myself had been contacted in the first place.
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This is gonna be good.... a great writer versus a professional mechanic? Epic.
 
Mr. CoolFiat
Oh nice, an industrial electrician? Sick.... never heard of that. :sick:
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Oh, just means I work on things like process control and machinery rather than domestic lights and power sockets, although I did my apprenticeship doing that stuff
 
thanks alot everyone, i talked with my proffessional mecanic(uncle) and he says it should just be a fuse, but hes never worked with a mr2 so he cant visualise which one it could be.
and also there is no damage done on the battery, when the sparks started i unhooked the leads and there was a 'pop' or 'pow' sound, thats why he thinks its a fuse that blew
 
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dodgeboy95
thanks alot everyone, i talked with my proffessional mecanic(uncle) and he says it should just be a fuse, but hes never worked with a mr2 so he cant visualise which one it could be.
and also there is no damage done on the battery, when the sparks started i unhooked the leads and there was a 'pop' or 'pow' sound, thats why he thinks its a fuse that blew
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Did you not read the above posts? They said some other things too. They too have their theories.
 
dodgeboy95
thanks alot everyone, i talked with my proffessional mecanic(uncle) and he says it should just be a fuse, but hes never worked with a mr2 so he cant visualise which one it could be.
and also there is no damage done on the battery, when the sparks started i unhooked the leads and there was a 'pop' or 'pow' sound, thats why he thinks its a fuse that blew
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That's usually the case when you put on battery leads wrong. I did this a couple months ago with my dads car and the same thing happened, I put the leads on wrong, got some sparks and a pop and then no ignition or anything when I put them back on the correct way. Checked the fuse box to find out the main fuse was blown. Swapped the fuse the next day and it started up just fine.
 
It's great now. There's a fusible link on the positive lead and that link burned and snaped like it's supposed to. Removed the burned end and hooked it back to the new battery THE RIGHT WAY and door ajar light came on so everything is good
 
homeforsummer
I've never had sparks when disconnecting and connecting batteries. If you're getting sparks you're almost certainly disconnecting/connecting the terminals in the wrong order.

I wasn't aware that you could choose which side the terminals are on, but even so it should be marked on the cover, and even if it isn't then you should have a fairly good idea which side they were on if you asked for it a particular way yourself.
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My battery always gives a small spark when reconnecting. Put the positive on first and then the neg and it happens every time
 
dodgeboy95
It's great now. There's a fusible link on the positive lead and that link burned and snaped like it's supposed to. Removed the burned end and hooked it back to the new battery THE RIGHT WAY and door ajar light came on so everything is good
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Oh jesus, Joel.
 

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