Why you should remove the negative battery terminal before doing ANYTHING!!!!
#61
Guest
Posts: n/a
Re: Why you should remove the negative battery terminal before doingANYTHING!!!!
Refinish King wrote:
> The very reason that using a wrong bulb:
>
> Will set a code on an OBD2 system.
that's load measurement, not inductance from a bulb filament coil.
>
> RK
>
> PS
> I'm not speculating on Jim's method of earning a living. But there are such
> instruments available.
of course! but i bet t.h. doesn't have any, and i'll bet he doesn't
know how to measure whether it has any noticeable effect!
> "jim beam" <spamvortex@bad.example.net> wrote in message
> news:eK-dnSP_xrPhEqfanZ2dnUVZ_qHinZ2d@speakeasy.net...
>> Tony Hwang wrote:
>>> jim beam wrote:
>>>
>>>> Tony Hwang wrote:
>>>>
>>>>> Dan_Thomas_nospam@yahoo.com wrote:
>>>>>
>>>>>> On Nov 11, 3:48 pm, "Steve W." <csr684...@yahoo.com> wrote:
>>>>>>
>>>>>>
>>>>>>> VERY WRONG. ECUs are easy to kill if you are not paying attention. My
>>>>>>> SOP in the body shop is to pull the ECU on anything that rolls in for
>>>>>>> panel work. One good zap from a welder can kill the ECU without being
>>>>>>> near it.
>>>>>>
>>>>>>
>>>>>> A welder and a dome light are vastly different things. An arc
>>>>>> welder generates a HUGE reactive voltage spike when striking the arc,
>>>>>> and that spike can wander all over the entire vehicle and fry
>>>>>> sensitive electronics and not-so-sensitive things, too, like
>>>>>> alternator diodes. Standard procedure there is to disconnect the
>>>>>> battery whenever doing any welding on the thing. Shorting a dome light
>>>>>> will NOT generate any sort of spike. Period. You need a coil to
>>>>>> generate spikes, coils like those found in starters, alternator
>>>>>> rotors, ignition coils. You might as well try to generate a spike by
>>>>>> disconecting and reconnecting the battery.
>>>>>>
>>>>>> Dan
>>>>>>
>>>>> Hmmm,
>>>>> Lamp filament is a tiny coil, LOL!
>>>>
>>>> with an air core and virtually no inductance. if you have instruments
>>>> that can measure any voltage spike you get from a coiled bulb filament,
>>>> i'd love to see your readings.
>>> Hmmm,
>>> You are so bone headed, can't even take a joke.
>>> The more you babble, the more you reveal your lack of knowledge:
>>> pratical or thory. My job used to deal with fraction of nano amps. VLSI,
>>> ASIC, etc. on mil-spec.
>> bullshitting idiot.
>
>
> The very reason that using a wrong bulb:
>
> Will set a code on an OBD2 system.
that's load measurement, not inductance from a bulb filament coil.
>
> RK
>
> PS
> I'm not speculating on Jim's method of earning a living. But there are such
> instruments available.
of course! but i bet t.h. doesn't have any, and i'll bet he doesn't
know how to measure whether it has any noticeable effect!
> "jim beam" <spamvortex@bad.example.net> wrote in message
> news:eK-dnSP_xrPhEqfanZ2dnUVZ_qHinZ2d@speakeasy.net...
>> Tony Hwang wrote:
>>> jim beam wrote:
>>>
>>>> Tony Hwang wrote:
>>>>
>>>>> Dan_Thomas_nospam@yahoo.com wrote:
>>>>>
>>>>>> On Nov 11, 3:48 pm, "Steve W." <csr684...@yahoo.com> wrote:
>>>>>>
>>>>>>
>>>>>>> VERY WRONG. ECUs are easy to kill if you are not paying attention. My
>>>>>>> SOP in the body shop is to pull the ECU on anything that rolls in for
>>>>>>> panel work. One good zap from a welder can kill the ECU without being
>>>>>>> near it.
>>>>>>
>>>>>>
>>>>>> A welder and a dome light are vastly different things. An arc
>>>>>> welder generates a HUGE reactive voltage spike when striking the arc,
>>>>>> and that spike can wander all over the entire vehicle and fry
>>>>>> sensitive electronics and not-so-sensitive things, too, like
>>>>>> alternator diodes. Standard procedure there is to disconnect the
>>>>>> battery whenever doing any welding on the thing. Shorting a dome light
>>>>>> will NOT generate any sort of spike. Period. You need a coil to
>>>>>> generate spikes, coils like those found in starters, alternator
>>>>>> rotors, ignition coils. You might as well try to generate a spike by
>>>>>> disconecting and reconnecting the battery.
>>>>>>
>>>>>> Dan
>>>>>>
>>>>> Hmmm,
>>>>> Lamp filament is a tiny coil, LOL!
>>>>
>>>> with an air core and virtually no inductance. if you have instruments
>>>> that can measure any voltage spike you get from a coiled bulb filament,
>>>> i'd love to see your readings.
>>> Hmmm,
>>> You are so bone headed, can't even take a joke.
>>> The more you babble, the more you reveal your lack of knowledge:
>>> pratical or thory. My job used to deal with fraction of nano amps. VLSI,
>>> ASIC, etc. on mil-spec.
>> bullshitting idiot.
>
>
#62
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Posts: n/a
Re: Why you should remove the negative battery terminal before doingANYTHING!!!!
Scott Dorsey wrote:
> jim beam <spamvortex@bad.example.net> wrote:
>> with an air core and virtually no inductance. if you have instruments
>> that can measure any voltage spike you get from a coiled bulb filament,
>> i'd love to see your readings.
>
> I do.
>
> BUT, you don't need one. If you have an 1141 lamp with 50 loops of
> 1/16" (that's estimated by eye here) about 1/2" long, you can use
> Wheeler's Formula:
>
> 50^2 * (0.065)^2 10.5
> --------------- = ----- = 0.27 microhenries
> 18 * 0.065 + 40 * 0.5 28.0
>
>
> That's a lot less than the hundreds of henries that an arc welder ballast
> will have, and it's probably small enough to be compensated for by the
> capacitance of the wiring, even.
excellent. and it's /well/ below any level that could /possibly/ impact
the ecu!
> But it's enough that you could measure it
> carefully with a scope and a pulse generator, even though it's actually
> going to be swamped at any reasonable voltage by the nonlinearity when the
> filament heats up and its resistance increases.
indeed.
> jim beam <spamvortex@bad.example.net> wrote:
>> with an air core and virtually no inductance. if you have instruments
>> that can measure any voltage spike you get from a coiled bulb filament,
>> i'd love to see your readings.
>
> I do.
>
> BUT, you don't need one. If you have an 1141 lamp with 50 loops of
> 1/16" (that's estimated by eye here) about 1/2" long, you can use
> Wheeler's Formula:
>
> 50^2 * (0.065)^2 10.5
> --------------- = ----- = 0.27 microhenries
> 18 * 0.065 + 40 * 0.5 28.0
>
>
> That's a lot less than the hundreds of henries that an arc welder ballast
> will have, and it's probably small enough to be compensated for by the
> capacitance of the wiring, even.
excellent. and it's /well/ below any level that could /possibly/ impact
the ecu!
> But it's enough that you could measure it
> carefully with a scope and a pulse generator, even though it's actually
> going to be swamped at any reasonable voltage by the nonlinearity when the
> filament heats up and its resistance increases.
indeed.
#63
Guest
Posts: n/a
Re: Why you should remove the negative battery terminal before doingANYTHING!!!!
jim beam wrote:
>
> excellent. and it's /well/ below any level that could /possibly/ impact
> the ecu!
>
You seem to forget that the dome light is 'live' all the time using a
ground as a switch.
They can have the glass fall out of the base and the loose internal
connecting wire(s) can and will cause a short circuit. This happens all
the time with bulbs such as the 1157 in taillights.
Short circuits can do nasty things to computers like blow the input
diode 'before' the fuse has a chance to blow.
It's not like the designers of modern vehicles are just BSing when they
say to unhook the negative before working on them.....
Mike
86/00 CJ7 Laredo, 33x9.5 BFG Muds, 'glass nose to tail in '00
'New' frame in the works for '08
>
> excellent. and it's /well/ below any level that could /possibly/ impact
> the ecu!
>
You seem to forget that the dome light is 'live' all the time using a
ground as a switch.
They can have the glass fall out of the base and the loose internal
connecting wire(s) can and will cause a short circuit. This happens all
the time with bulbs such as the 1157 in taillights.
Short circuits can do nasty things to computers like blow the input
diode 'before' the fuse has a chance to blow.
It's not like the designers of modern vehicles are just BSing when they
say to unhook the negative before working on them.....
Mike
86/00 CJ7 Laredo, 33x9.5 BFG Muds, 'glass nose to tail in '00
'New' frame in the works for '08
#64
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Posts: n/a
Re: Why you should remove the negative battery terminal before doingANYTHING!!!!
Hachiroku ãƒãƒãƒã‚¯ wrote:
\
>
> Well, he didn't really wreck it. He had a bad bulb in the overhead light.
> He removed the lens, and the bulb was in pieces, but still working
> intermittantly. He removed the bulb and replaced the lens, and then tried
> to start the truck. No Go. The starter spins, but the engine doesn't catch.
>
> Looks like he fried the ECU!!!! All the other lights work, the dome light
> works, but the fuel pumpo doesn't energize. He tried the reset procedure
> and nothing.
>
> I had heard of this before; I can't remember what the car was, but someone
> shorted out the ECU replacing the dome light...
>
>
I don't buy it. ECUs are actually *very* well protected against
intermittent faults, voltage spikes, etc. (Zener diodes are a wonderful
thing). 99.9% of the "failed" ECUs people pull out of cars are actually
fine and the problem lies elsewhere. There's no WAY you can hurt one
just changing a light bulb.
\
>
> Well, he didn't really wreck it. He had a bad bulb in the overhead light.
> He removed the lens, and the bulb was in pieces, but still working
> intermittantly. He removed the bulb and replaced the lens, and then tried
> to start the truck. No Go. The starter spins, but the engine doesn't catch.
>
> Looks like he fried the ECU!!!! All the other lights work, the dome light
> works, but the fuel pumpo doesn't energize. He tried the reset procedure
> and nothing.
>
> I had heard of this before; I can't remember what the car was, but someone
> shorted out the ECU replacing the dome light...
>
>
I don't buy it. ECUs are actually *very* well protected against
intermittent faults, voltage spikes, etc. (Zener diodes are a wonderful
thing). 99.9% of the "failed" ECUs people pull out of cars are actually
fine and the problem lies elsewhere. There's no WAY you can hurt one
just changing a light bulb.
#65
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Posts: n/a
Re: Why you should remove the negative battery terminal before doingANYTHING!!!!
jim beam wrote:
> Hachiroku wrote:
> <snip crap>
>
>> I had heard of this before; I can't remember what the car was, but
>> someone
>> shorted out the ECU replacing the dome light...
>
>
> no way - the ecu's not even connected to the dome light.
That much is not true in all cases. Any care that has "theater fade"
interior lights, for example, has them powered from a computer module
(not necessarily the engine controller, but a "body controller" or some
other computer module.)
> and they're
> electrically protected against all kinds of "user error", including
> battery reversal, over-voltage, dead shorts and static. short of direct
> lightning strike, water damage, or fire, none of which have a single
> damned thing to do with dome lights, the ecu's not going anywhere and
> it's /certainly/ not going to be fubared by a bulb change.
And on all of THAT, I agree completely!
> Hachiroku wrote:
> <snip crap>
>
>> I had heard of this before; I can't remember what the car was, but
>> someone
>> shorted out the ECU replacing the dome light...
>
>
> no way - the ecu's not even connected to the dome light.
That much is not true in all cases. Any care that has "theater fade"
interior lights, for example, has them powered from a computer module
(not necessarily the engine controller, but a "body controller" or some
other computer module.)
> and they're
> electrically protected against all kinds of "user error", including
> battery reversal, over-voltage, dead shorts and static. short of direct
> lightning strike, water damage, or fire, none of which have a single
> damned thing to do with dome lights, the ecu's not going anywhere and
> it's /certainly/ not going to be fubared by a bulb change.
And on all of THAT, I agree completely!
#66
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Posts: n/a
Re: Why you should remove the negative battery terminal before doingANYTHING!!!!
Tony Hwang wrote:
> jim beam wrote:
>> yeah, it could have been hit by meteorite.
>
> hmmm,
> Whatever you think. A car battery has lots of energy in it.
> Think current in this case.
Think "fuse" in this case.... unless it was one of those Chinese-made
fuses from Harbor Freight... ;-)
> jim beam wrote:
>> yeah, it could have been hit by meteorite.
>
> hmmm,
> Whatever you think. A car battery has lots of energy in it.
> Think current in this case.
Think "fuse" in this case.... unless it was one of those Chinese-made
fuses from Harbor Freight... ;-)
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