ECU Problems

[tomtom]

Can you explain that a bit more?

bump. I sitll dont get what you did with your battery. I've taken my wires off all sorts of different combinations (positive first, negative first, slap my penis on the battery cover first etc) and nothing has ever gone wrong.

All i've known is you take the negative terminal off first as a safety precaution (for yourself).

Ie: if you were using a spanner to undo the bolt on positive first and your spanner touches, i unno, something that completes the circuit, you die (from a 12V lol).

Whereas if you were undoing the negative, nothing will happen... and when you go to do the positive theres no circuit.



Glad to hear your car is back to running again. After those suspension upgrades habibs come to Wakefield. I'm hoping to go again in mid sem break in September.

[gman]

You take them off in order to prevent voltage spikes that can fry ECU's more than anything to protect you as the remover of the battery leads.

If your using a spanner on the positive terminal and you touch anything that earths the battery, your still going to get a huge spark and spike (nothing like a little impromptu arc welding)...

Undoing the negative terminal first may just stop it going through the cars system. However if you earth the positive terminal and lead to the car/engine/body etc it may not as the electrical system earths there anyway...

Its the same same concept as the jumper cables that have the voltage arrestors in them to prevent sudden voltage spikes.

[tomtom]

You take them off in order to prevent voltage spikes that can fry ECU's more than anything to protect you as the remover of the battery leads.

If your using a spanner on the positive terminal and you touch anything that earths the battery, your still going to get a huge spark and spike (nothing like a little impromptu arc welding)...

Undoing the negative terminal first may just stop it going through the cars system. However if you earth the positive terminal and lead to the car/engine/body etc it may not as the electrical system earths there anyway...

Its the same same concept as the jumper cables that have the voltage arrestors in them to prevent sudden voltage spikes.

cheers Gman. Now i know

[SA33DS]

Lol, penis on battery??

cool how does it feel??

i dont know but i think what caused it was that i just removed the battery without doing it within the 10 second period from turning the ignition off.....

maybe

[AfterBurner]

You take them off in order to prevent voltage spikes that can fry ECU's more than anything to protect you as the remover of the battery leads.

If your using a spanner on the positive terminal and you touch anything that earths the battery, your still going to get a huge spark and spike (nothing like a little impromptu arc welding)...

Undoing the negative terminal first may just stop it going through the cars system. However if you earth the positive terminal and lead to the car/engine/body etc it may not as the electrical system earths there anyway...

Its the same same concept as the jumper cables that have the voltage arrestors in them to prevent sudden voltage spikes.

I don't understand this, if you break the circuit, it's broken... If you disconnect the negative first, the circuit is broken as TomTom said...

I don't care either way but, TomTom is right in saying that if you short the spanner to body with the Negative connected, you WILL arc weld the spanner to your body, if the NEGATIVE is off, this cannot possibly happen, the only thing that can happen is you will get a spark if you touch the Positive to the body as it discharges the Capacitors in the car's electrics, esp if you have big amps/subs etc... I personally have never seen nor heard of a car being damaged from doing it or not doing it in a certain order.

I even used OFC Speaker cable that was for my subs once to start my old Falcon when i had no Jumper leads, worked fine... Mind you i had to double it back to get enough current to run thru...

In essence, a circuit is a circuit, no matter which way you connect/disconnect, the electrons will still flow the same way...

my 2c.

ps. TomTom, 12v will not kill you unless you put 2x 1" nails in either side of your Penis & hook it up directly with no resistance in the circuit, even then it probably still won't kill you... You need the Volts to carry the Amps...

pps. Glad to hear the car is fine dude... I think Holden luv us Opel heads, means more $$$'s for 'em...

[gman]

I don't understand this, if you break the circuit, it's broken... If you disconnect the negative first, the circuit is broken as TomTom said...

Correct..The circuit is broken to the cars electrics if you remove either the negative OR the positive..Agreed...But if you remove the positive first or you may short circuit the positive terminal to a grounded part of the car causing a voltage spike through the system. Also, removing the negative first stops voltage spikes as you remove the positive terminal WHILE the circuit is still completed throughthe battery which saves electronics as the current flows FROM POSITIVE to NEGATIVE.

I don't care either way but, TomTom is right in saying that if you short the spanner to body with the Negative connected, you WILL arc weld the spanner to your body,

Absolutely, we agreed on that...Negative connected or not, touch anything metal from the positive terminal to the body, you will arc weld it to the car...

if the NEGATIVE is off, this cannot possibly happen,

Ummm, I think I disagree...If the Negative is disconnected and you touch anything metal from the Positive terminal to the body you are completing the circuit and it will still spark to the body just a badly...If you mean the Positive lead, thats a different story.....

the only thing that can happen is you will get a spark if you touch the Positive to the body as it discharges the Capacitors in the car's electrics, esp if you have big amps/subs etc... I personally have never seen nor heard of a car being damaged from doing it or not doing it in a certain order.

I think this is where we're getting confused...By battery terminal, do you mean the actual terminal on the battery or the lead that attaches to it?

If you take the lead off the battery it will not spark against body if you let to touch it...

In essence, a circuit is a circuit, no matter which way you connect/disconnect, the electrons will still flow the same way...

They only flow one way... But I think we're saying the same thing....The issue comes where there is a possibility of sending a voltage spike through the system (completing the circuit) while the positive is still connected and thats what fries electronics like ECU's

[AfterBurner]

Ummm, I think I disagree...If the Negative is disconnected and you touch anything metal from the Positive terminal to the body you are completing the circuit and it will still spark to the body just a badly...If you mean the Positive lead, thats a different story.....

OK here's the point i mean, im not being argumentative btw Gman, just clarifying the point, IF the circuit is broken, its broken. It doesn't matter if you break POSITIVE or NEGATIVE, the circuit is incomplete, therefore, no matter what you touch to the car body, whether it be the Positive OR Negative terminal makes no difference, so long as the battery has been isolated, ie. 1 lead is removed... UNLESS you still have the NEGATIVE connected then short the positive battery terminal to the car body, in essence your placing the spanner across the battery (now a welding rod)... If you touch the positive lead to the body, you will get a spark which is just residual current left over in the system, IMO shouldn't cause any damage...

So disconnecting the Negative first is a wise choice, as for re-connecting, doesn't matter so long as you don't do it backwards!!!

As for Voltage Spikes - Impossible. Surge, maybe but doubtful... A spike in general would mean 'Over-Voltage' which cannot happen unless your regulator/alternator is rooted & passes AC thru with the engine running because your rectifier is shot (4 diode matrix inside the Alternator). Remember - a car battery is a 12v cell, so, you can't get more than 12v from it!

The other point worth a mention... 'Conventional Current flow' is indeed Positive to Negative, but, 'Electron Flow' is from Negative to Positive... Confusing i know

Hope that clears things up, i think we both mean the same thing but are saying it differently???

...

[gman]

OK here's the point i mean, im not being argumentative btw Gman, just clarifying the point, IF the circuit is broken, its broken. It doesn't matter if you break POSITIVE or NEGATIVE, the circuit is incomplete, therefore, no matter what you touch to the car body, whether it be the Positive OR Negative terminal makes no difference, so long as the battery has been isolated, ie. 1 lead is removed... UNLESS you still have the NEGATIVE connected then short the positive battery terminal to the car body, in essence your placing the spanner across the battery (now a welding rod)... If you touch the positive lead to the body, you will get a spark which is just residual current left over in the system, IMO shouldn't cause any damage...

So disconnecting the Negative first is a wise choice, as for re-connecting, doesn't matter so long as you don't do it backwards!!!

As for Voltage Spikes - Impossible. Surge, maybe but doubtful... A spike in general would mean 'Over-Voltage' which cannot happen unless your regulator/alternator is rooted & passes AC thru with the engine running because your rectifier is shot (4 diode matrix inside the Alternator). Remember - a car battery is a 12v cell, so, you can't get more than 12v from it!

The other point worth a mention... 'Conventional Current flow' is indeed Positive to Negative, but, 'Electron Flow' is from Negative to Positive... Confusing i know

Hope that clears things up, i think we both mean the same thing but are saying it differently???

...

I think you might be right...

[tomtom]

what the FK just happened in the last few posts lol?

I'm just going to say i'll be doing negative first as Ive always done.... because thats the way papa told me to.

ps. TomTom, 12v will not kill you unless you put 2x 1" nails in either side of your Penis & hook it up directly with no resistance in the circuit, even then it probably still won't kill you... You need the Volts to carry the Amps...

lolo i know thats why i said "from a 12v lol".