Re: 2003 Tiburon - no spark
#31
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Posts: n/a
Re: 2003 Tiburon - no spark - reply to Bob
"nothermark" <trash@gnomex.cotse.net> wrote in message
news:4uhnv1hj2970evtgkp79i5lsv5u98v58fr@4ax.com...
> took this out of the other thread because it's less relevant to his
> problem.
>
> On Mon, 20 Feb 2006 21:46:19 -0500, "Bob" <bobsjunkmail@bellsouth.net>
> wrote:
>
>
> I think he indicated the problem circuit does not include the O2
> sensor. I'm not too worried about the power draw as long as he does
> not jumper the fuse with a large wire. As you pointed out, and he
> measured, the current is limited to around 12 - 15 A so On times of 10
> seconds or so won't do more than run down the battery or blow the bad
> sensor open. Even melting something is not all bad as it points out
> the problem. The only thing I would feel bad about there is one wire
> in a large bundle and it took out the bundle.
Which is my concern. At 15 amps, something is getting hot. I would prefer
not to torch something in the harness.
>>
>>>
>>> Polarity probably will also be an issue. You are going to need to use
>>> the positive voltage resistance lead on the power lead to the sensor.
>>> If you are not sure what one that is use a second meter set to measure
>>> voltage and measure the voltage accross the probes of your resistance
>>> meter.
>>
>>If he's got a digital meter, most of them will not forward bias any diodes
>>present in things like position sensors, so he won't even see them. They
>>are
>>not likely culprits anyway.
>
> I was thinking more about a reverse polarity diode accross the sensor.
> I've seen them on a lot of automotive comm gear as the power from the
> alternator is pretty dirty. Most meters will detect that. That's how
> we check transistors. ;-)
>
It really depends on the meter. I typically use Fluke 73s. In ohms mode,
they don't "see" diodes real well. That is done intentionally. They do have
a mode for looking at semiconductor junctions.
>
>>
>>> Once You know the polarity probe the leads to the sensors with any
>>> ground lead connected to the chassis. I bet several will be over 100
>>> ohms so you can discount them for a first pass. If one is clearly
>>> below 2 or 3 ohms it is probably the problem. If all of them look OK
>>> then it is probably a function of the sensor activating and drawing
>>> too much current. The easiest way to find that will be to disconnect
>>> all of them then reconnect one at a time. You can either wait for the
>>> fuse to blow or connect an ammeter across a blown fuse. Monitor the
>>> current draw as each sensor is connected. If I was doing this much
>>> that is what I would start with. ;-)
>>
>>If he puts an ammeter (like the one in his meter) across the open fuse,
>>he'll either cook his meter, or blow the current fuse in it (if there is
>>one).
>
> Not really. It's already taking several seconds to blow the fuse so
> we know the current is limited. A 20 or 50 A current meter like he
> needs is pretty rugged. What I think I advised is that he pull all
> the sensor wires and put them back as he watched the meter. I assumed
> he would turn off the power or pull off the lead if he pegged the
> meter. Perhaps I assume too much?
>
We really don't know what kind of meter he has. The less expensive meters
have a fuse on the low current path, and nothing but a current shunt on the
high current path. Cat. III / IV meters like the ones I use are actually
fused at relatively low values - 440 ma, and 11 amps for the high current
port. For high current DC I use either an external shunt, or a DC clamp on.
For AC, I normally use a clamp on. The DC systems I work on can have
available source currents as high as 40,000 amps at voltages from 12 on up
to 480 volts. I also work on switching equipment and control systems for
voltages as high as 230,000 volts at lots of current.
So, maybe you can understand why I'm not real big on the keep feeding it
fuses technique.
In automotive, it might work without major issues, but it may also
eventually damage something besides what is already broken. feeding a line
with a current limited source - either a fancy power supply, or a lamp as a
ballast resistor - is a pretty effective technique. When you've isolated it
to one line, and it's a wiring issue, you can feed that line from either
end, and determine which end the fault to ground is closer to, and maybe
even estimate relative distance. I work on a wide variety of DC powered
devices that communicate with serial data, tones, voltages, and currents.
The things I recommended against are just things I cannot do because I have
to be very careful not to cause additional damage, as repeatedly re-fusing a
known failed circuit - even in a car - can do.
>
>>Something that works well - if you don't have access to a current limited
>>power supply - is to use a high current lamp - like one or both filaments
>>in
>>a 60 watt headlamp - in place of the fuse. Low current flow = no heating
>>of
>>filament, so little drop across it. Short to ground = light lights, and
>>current is limited to about 5 amps for one filament, or about 10 amps for
>>2
>>in parallel. In either case, you can start disconnecting (or connecting)
>>things and watch continuously for what changes.
>
> Your way is more elegant, just takes more fussing around. If I was
> doing much trouble shooting I would probably build a lamp bank. I was
> giving him a one shot quicky approach.
>
>
I'm disputing that your suggestion will work. It just makes me cringe when
you suggested shorting across a blown fuse with an ammeter when we are not
sure whether that is fused, or will just melt. Also, the assumption that
he'll get his meter off it fast enough is another variable.
>>
>>
>>> If the fuse is blowing with the key on but not cranking the engine I
>>> bet you will find the answer fairly easily. You probaly have a blown
>>> semiconductor junction. It still has resistance, as does the
>>> packaging leads, but it's well below what it should be.
>>>
>>> nothermark
>>
#32
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Posts: n/a
Re: 2003 Tiburon - no spark - reply to Bob
"Bob" <bobsjunkmail@bellsouth.net> wrote in message
news:aRRKf.22794$Ly6.15559@bignews5.bellsouth.net. ..
>> Your way is more elegant, just takes more fussing around. If I was
>> doing much trouble shooting I would probably build a lamp bank. I was
>> giving him a one shot quicky approach.
>>
Uhhhh..... That would be...... I'm NOT disputing..... Trigger finger a
little quick on the send button...
> I'm disputing that your suggestion will work. It just makes me cringe when
> you suggested shorting across a blown fuse with an ammeter when we are not
> sure whether that is fused, or will just melt. Also, the assumption that
> he'll get his meter off it fast enough is another variable.
>>>
>>>
#33
Guest
Posts: n/a
Re: 2003 Tiburon - no spark - reply to Bob
"Bob" <bobsjunkmail@bellsouth.net> wrote in message
news:aRRKf.22794$Ly6.15559@bignews5.bellsouth.net. ..
>> Your way is more elegant, just takes more fussing around. If I was
>> doing much trouble shooting I would probably build a lamp bank. I was
>> giving him a one shot quicky approach.
>>
Uhhhh..... That would be...... I'm NOT disputing..... Trigger finger a
little quick on the send button...
> I'm disputing that your suggestion will work. It just makes me cringe when
> you suggested shorting across a blown fuse with an ammeter when we are not
> sure whether that is fused, or will just melt. Also, the assumption that
> he'll get his meter off it fast enough is another variable.
>>>
>>>
#34
Guest
Posts: n/a
Re: 2003 Tiburon - no spark - reply to Bob
"Bob" <bobsjunkmail@bellsouth.net> wrote in message
news:aRRKf.22794$Ly6.15559@bignews5.bellsouth.net. ..
>> Your way is more elegant, just takes more fussing around. If I was
>> doing much trouble shooting I would probably build a lamp bank. I was
>> giving him a one shot quicky approach.
>>
Uhhhh..... That would be...... I'm NOT disputing..... Trigger finger a
little quick on the send button...
> I'm disputing that your suggestion will work. It just makes me cringe when
> you suggested shorting across a blown fuse with an ammeter when we are not
> sure whether that is fused, or will just melt. Also, the assumption that
> he'll get his meter off it fast enough is another variable.
>>>
>>>
#35
Guest
Posts: n/a
Re: 2003 Tiburon - no spark - reply to Bob
"Bob" <bobsjunkmail@bellsouth.net> wrote in message
news:aRRKf.22794$Ly6.15559@bignews5.bellsouth.net. ..
>
>
> We really don't know what kind of meter he has. The less expensive meters
> have a fuse on the low current path, and nothing but a current shunt on
the
> high current path. Cat. III / IV meters like the ones I use are actually
> fused at relatively low values - 440 ma, and 11 amps for the high current
> port. For high current DC I use either an external shunt, or a DC clamp
on.
> For AC, I normally use a clamp on. The DC systems I work on can have
> available source currents as high as 40,000 amps at voltages from 12 on up
> to 480 volts. I also work on switching equipment and control systems for
> voltages as high as 230,000 volts at lots of current.
> So, maybe you can understand why I'm not real big on the keep feeding it
> fuses technique.
>
> In automotive, it might work without major issues, but it may also
> eventually damage something besides what is already broken. feeding a line
> with a current limited source - either a fancy power supply, or a lamp as
a
> ballast resistor - is a pretty effective technique. When you've isolated
it
> to one line, and it's a wiring issue, you can feed that line from either
> end, and determine which end the fault to ground is closer to, and maybe
> even estimate relative distance. I work on a wide variety of DC powered
> devices that communicate with serial data, tones, voltages, and currents.
> The things I recommended against are just things I cannot do because I
have
> to be very careful not to cause additional damage, as repeatedly re-fusing
a
> known failed circuit - even in a car - can do.
>
>
I'm just getting caught up on this thread and have read the conversations
between you and northmark. Good stuff. I have to say - I have used the
technique of throwing a bulb in the circuit as a current limiter. It's a
great technique for more than one reason. Besides providing the current
limiting benefit, it also gives a pretty visible, easy to "read" indication,
which is often times a big plus when working on car wiring. I wish I had
thought a little further down the troubleshooting process to have
recommended that Bob.
--
-Mike-
mmarlowREMOVE@alltel.net
#36
Guest
Posts: n/a
Re: 2003 Tiburon - no spark - reply to Bob
"Bob" <bobsjunkmail@bellsouth.net> wrote in message
news:aRRKf.22794$Ly6.15559@bignews5.bellsouth.net. ..
>
>
> We really don't know what kind of meter he has. The less expensive meters
> have a fuse on the low current path, and nothing but a current shunt on
the
> high current path. Cat. III / IV meters like the ones I use are actually
> fused at relatively low values - 440 ma, and 11 amps for the high current
> port. For high current DC I use either an external shunt, or a DC clamp
on.
> For AC, I normally use a clamp on. The DC systems I work on can have
> available source currents as high as 40,000 amps at voltages from 12 on up
> to 480 volts. I also work on switching equipment and control systems for
> voltages as high as 230,000 volts at lots of current.
> So, maybe you can understand why I'm not real big on the keep feeding it
> fuses technique.
>
> In automotive, it might work without major issues, but it may also
> eventually damage something besides what is already broken. feeding a line
> with a current limited source - either a fancy power supply, or a lamp as
a
> ballast resistor - is a pretty effective technique. When you've isolated
it
> to one line, and it's a wiring issue, you can feed that line from either
> end, and determine which end the fault to ground is closer to, and maybe
> even estimate relative distance. I work on a wide variety of DC powered
> devices that communicate with serial data, tones, voltages, and currents.
> The things I recommended against are just things I cannot do because I
have
> to be very careful not to cause additional damage, as repeatedly re-fusing
a
> known failed circuit - even in a car - can do.
>
>
I'm just getting caught up on this thread and have read the conversations
between you and northmark. Good stuff. I have to say - I have used the
technique of throwing a bulb in the circuit as a current limiter. It's a
great technique for more than one reason. Besides providing the current
limiting benefit, it also gives a pretty visible, easy to "read" indication,
which is often times a big plus when working on car wiring. I wish I had
thought a little further down the troubleshooting process to have
recommended that Bob.
--
-Mike-
mmarlowREMOVE@alltel.net
#37
Guest
Posts: n/a
Re: 2003 Tiburon - no spark - reply to Bob
"Bob" <bobsjunkmail@bellsouth.net> wrote in message
news:aRRKf.22794$Ly6.15559@bignews5.bellsouth.net. ..
>
>
> We really don't know what kind of meter he has. The less expensive meters
> have a fuse on the low current path, and nothing but a current shunt on
the
> high current path. Cat. III / IV meters like the ones I use are actually
> fused at relatively low values - 440 ma, and 11 amps for the high current
> port. For high current DC I use either an external shunt, or a DC clamp
on.
> For AC, I normally use a clamp on. The DC systems I work on can have
> available source currents as high as 40,000 amps at voltages from 12 on up
> to 480 volts. I also work on switching equipment and control systems for
> voltages as high as 230,000 volts at lots of current.
> So, maybe you can understand why I'm not real big on the keep feeding it
> fuses technique.
>
> In automotive, it might work without major issues, but it may also
> eventually damage something besides what is already broken. feeding a line
> with a current limited source - either a fancy power supply, or a lamp as
a
> ballast resistor - is a pretty effective technique. When you've isolated
it
> to one line, and it's a wiring issue, you can feed that line from either
> end, and determine which end the fault to ground is closer to, and maybe
> even estimate relative distance. I work on a wide variety of DC powered
> devices that communicate with serial data, tones, voltages, and currents.
> The things I recommended against are just things I cannot do because I
have
> to be very careful not to cause additional damage, as repeatedly re-fusing
a
> known failed circuit - even in a car - can do.
>
>
I'm just getting caught up on this thread and have read the conversations
between you and northmark. Good stuff. I have to say - I have used the
technique of throwing a bulb in the circuit as a current limiter. It's a
great technique for more than one reason. Besides providing the current
limiting benefit, it also gives a pretty visible, easy to "read" indication,
which is often times a big plus when working on car wiring. I wish I had
thought a little further down the troubleshooting process to have
recommended that Bob.
--
-Mike-
mmarlowREMOVE@alltel.net
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