Jump to content
Geno

Piercing leads for testing

Recommended Posts

Agreed with WHNUT if you have all this experience why are you asking the same question over and over other than to debate your point in the first place. Just fix the wire and be done

Share this post


Link to post
Share on other sites

Show me the answer please, I don't see it anywhere.   :)  

Share this post


Link to post
Share on other sites

Show me the answer please, I don't see it anywhere.   :)  

:banghead:

  • Like 1

Share this post


Link to post
Share on other sites

When diagnosing an electrical problem, expedience is the driving force. Time is money. The ultimate and most best practice may be not to ever pierce a wire. That is a given. The question is will it harm a circuit to pierce a wire. Under most cases I would suggest that it will not.

 

Now if you were to take a wire bundle and start piercing most of the wires in that bundle in the same spot, there is a chance you could cause a very high voltage to jump across to the wire next to it. But who would do that? If I had to pierce several wires in the same bundle I would make sure that I staggered the point of piercing to prevent arcing. We don't deal with high voltages in this type of repair except for the coil and it would never be necessary to pierce a coil wire as it is always easy to test continuity from one end to the other.  

 

Pierce a wire and then dunk it in a pail of water, Remove it and run voltage through it. You won't see voltage arcs jumping around like a horror movie. We are talking 12 volts here at 30 amps or less. mostly less. Ten years down the road that wire will still carry 12 volts at 30 amps and you won't see any corrosion either.

 

This is a silly argument. If you don't want to pierce a wire then  take the extra hours of your time to diagnose the problem in the best practice manner. If that is what works for you than that's what you should do.

 

There are times when getting to the source of a wire is just about impossible. Especially when working on cars. The wiring is placed in the vehicle before the instruments and seats and a sundry of other things are placed in the vehicle. Wires run through door panels and under rugs and in the headliner. In my Cadillac, to get at some of the rear lights, I have to dismantle part of the trunk lid. the engine is mounted sideways and to get to wiring behind the engine, you need to take the top motor mounts lose and pull the engine forward. I'm not doing that. I will pierce the wire where I can get at it.   

 

This is a matter of opinion. Every one has an opinion and is entitled to it. It is not worth arguing about. I sense that some folks are really agitated over this. Looks like it is about to get nasty. Since I started to write this post, I have received notice that there are six more replies. That is real activity for such a trivial matter.

  • Like 3

Share this post


Link to post
Share on other sites

Voltage drop does not mean arching. It means the ability of the wire to carry the load. If you are going to pierce the wire it needs to be resealed.

 

 

 

 

"Looks like it is about to get nasty"

 

 Not nasty at all, but we don't agree, but that's what life is all about.

Edited by WH nut

Share this post


Link to post
Share on other sites

Voltage drop does not mean arching. It means the ability of the wire to carry the load. If you are going to pierce the wire it needs to be revealed.

And that can be easily accomplished with liquid tape...

I'm gonna chime in with my two pennies.. I don't do wiring for a living but yes I can troubleshoot and fix when I have to. It's not going to hurt the wire if it's resealed. Be as good as new and last just as long...

So if you want to do it your way by all means... Do it your way. I'll do it mine, and if I ever need Geno to do any wiring for me... I have faith in his way and his willingness to stand behind it.

Different doesn't always mean wrong... Just means different. You take the scenic route and I'll take the expressway... In the end... We both get to our destination. I'm just there first and playing on my horses.

  • Like 3

Share this post


Link to post
Share on other sites

Voltage drop does not mean arching. It means the ability of the wire to carry the load. If you are going to pierce the wire it needs to be resealed.

 

 

 

 

"Looks like it is about to get nasty"

 

 Not nasty at all, but we don't agree, but that's what life is all about.

Piercing the wire will not cause a voltage drop.

  • Like 3

Share this post


Link to post
Share on other sites

Okie dokie folks. have fun with this

Share this post


Link to post
Share on other sites

I'm gonna answer #4 if that ends this thread

 

Thank you, that's all I wanted was an answer.  :laughing-rolling:

 

 

It shouldn't get nasty Nick.  I just asked an honest question about what someone would do in a situation and was trying to get an answer.   :handgestures-thumbsup: 

  • Like 3

Share this post


Link to post
Share on other sites

  Not to add more junk to the thread but I like a good debate. I think the problem is not arching as an issue but rather corrosion. Most wire in our cars and horses will be copper stranded. When copper stranded starts to corrode it insulates the copper strands from each other and cause resistance / heat. Having experience in outdoor railroading. I have buried miles of wire in ground with and without conduit. I have seen copper wire turn green almost two feet into the insulation from moisture wicking its way up the insulation. This reaction was from extreme weather and climate conditions and not having properly tinned leads and sealed connectors. Even then , moisture finds its way in under ground.

 

  That being said, most all of our horse will never see the extreme condition needed to be met to cause this type of failure in the wire. Our connections are not weather proof and moisture has plenty of ways to find its way into our wiring harness but I never see major issues. On the other hand. I dont like to splice wires but I believe the pin prick of this tool would cause no foul play or damage in most applications. Unless you want to bury the tractor in the dirt for a few years..... Seal it with some liquid tape and rest at peace at night if you wish.

 

 

 Looking at it from a cars angle. If the wire is a brake light or fuel sending unit wiring under the frame in wet areas , I might opt to replace the wire instead of splicing the damaged area. Moisture and salt can reak havoc. My trailor wiring never fails me but I can bet you will not find crimp on connectors in my wiring. All soldered and heat shrink. I hate fussing with trailor lights and see way to many people year after year fighting this issue. Under the hood or interior . Sure poke away with your tool but 99% of the time the wiring harness is hidden under wiring loom or taped up anyway which still has you tearing the harness apart in the first place and poking along till you find it. My opinion, replace or run new wire and save me the shop labor.  Rendering the use of the tool you speak of useless.

 

   In my opinion, any time I wish I had that tool in my box was when I wanted to test readings off of , lets say, a throttle position sensor while it was still on the car to determine if it needed replacing or not. And the plug was sealed up nice and tight and there is no way to get my meter probes anywhere near wires. Just my opinion. I think this tool has applications and is worth having around. For a horse, you can usually sneak the probes of your meter behind any plug, or fuze needed. Also no miles of wire found on the wheel horses, I just replace if there is an issue most of the time. For a quick fix , out comes the Weller solder station and heat shrink. never fails me.

 

  Kyle

Edited by Theroundhousernr
  • Like 4

Share this post


Link to post
Share on other sites

Good points there.   :handgestures-thumbsup:  

 

The one thing I can not do is use solder.  Most manufacturers will not allow it as a viable repair.  I learned this through many years of warranty work as I do a lot of electrical for dealers on vehicles still under factory warranty.  The only thing they will allow is a shrinkable butt connector.  The connectors even come with any exterior pigtails.

 

The problem with running a new wire is if you have to go from the engine compartment to the interior it is incredibly more time consuming than picking select areas in the harness and opening it up to narrow down the problem.  Another big thing here also is time is money, I do this for a living and cost factors in and we all know we have to keep the customer happy.  The next problem is protection of the new wire, as well as the sealing of it if you can get it into the interior at all without making a hole in the car.  Finally, this repair if done by my shop will be guaranteed for life, a big thing to factor in when doing the repair.  I don't like doing something a second time for free and putting the customer out.  :)

 

 I have a neat little tool I'll try to get some pics of today.  Doesn't work in every scenario though.  It's a device that you plug into a circuit that broadcasts a radio frequency into the circuit.  It has a wireless handheld receiver with arrows that guides you right to the problem.  I'm surprised that no one has mentioned it, but even most electronic experts have never even heard of it.  Must be the OCD again.  :laughing-rolling:

  • Like 3

Share this post


Link to post
Share on other sites

   I have heard of that tool and would love to get me one. Many times I could have used something like that. I have a tool that plugs into house hold sockets and sends a signal over the AC wave forms. Then I can go to the breaker box and search what breaker that particular receptacle is attached to with a hand held unit that produces a high pitch signal like a metal detector when I hover over the right breaker. Has been the best tool in the world with houses that were wired by Tim the tool man Taylor and unmarked breakers!

 

  Lets see a picture!

  • Like 1

Share this post


Link to post
Share on other sites

Power Probe makes on, works nice

post-1982-0-98556300-1414028107_thumb.jp

Edited by WH nut
  • Like 2

Share this post


Link to post
Share on other sites

You have one too? 

Share this post


Link to post
Share on other sites

Of course I do

  • Like 2

Share this post


Link to post
Share on other sites

I've been waiting this whole thread for someone to tell me about those, weird.   Here's mine.

 

 

post-13404-0-21867800-1414075853_thumb.j

  • Like 1

Share this post


Link to post
Share on other sites

Geno,

My answer to you question is 4.

I work on aircraft for a living and in my world 4 is the only answer unless you can find a break using a megger.

      Caution: always have electronic components disconnected at both ends of the harness when using a megger.

Then if you must splice a wire it is always with a sealing splice.

 

Clark

  • Like 2

Share this post


Link to post
Share on other sites

You work in a whole lot more risky business than I do, thanks for the answer.

 

Also, :WRS:

  • Like 2

Share this post


Link to post
Share on other sites

I dont work on cars much, but in my business I use a time-domain reflectometer.

 

Sends a pulse down a wire and measures the reflection when the pulse hits the end of the wire. Wouldnt be very practical in your situation most of the time but just to add to the "electronic solutions"

 

The one I used could measure a high resistance are or break within .5" and was about $10K...

 

:handgestures-thumbupright:

  • Like 1

Share this post


Link to post
Share on other sites

Brandon,

That's what we use as well.

Those Fox and Hounds work fine as long as the harness is accessible.

You get a harness that is out of reach and a TDR will give you a distance from the meter, so you can locate a defect easier.

The one we have at work was about $8K.

 

Clark

  • Like 1

Share this post


Link to post
Share on other sites

I dont work on cars much, but in my business I use a time-domain reflectometer.

 

Sends a pulse down a wire and measures the reflection when the pulse hits the end of the wire. Wouldnt be very practical in your situation most of the time but just to add to the "electronic solutions"

 

The one I used could measure a high resistance are or break within .5" and was about $10K...

 

:handgestures-thumbupright:

 

If you already have a decent o'scope, you can build a fast rise pulse generator for around $10 that will do the exact same thing as the $10K piece. You just have to do a pencil and paper calculation to find the distance. TDR works great on coax cable or paired cables but may be difficult to work with in an automotive environment. The ground plane needed for TDR to be performed is non predictable in the automobile due to changing cable distance from   grounded metal. 

 

Edited by Save Old Iron
  • Like 2

Share this post


Link to post
Share on other sites

After all this chatter I figured I need to do a little more investigation on the claims made in the post.

 

A little poke here and another one there .... let's go back and check that once again, and all of a sudden you have the same issue but now your wiring harness feels like this guy feels.

 

porcp1_zpsbc33b870.jpg

 

 

I decided to finally break out my wire piercing adapters I have had in storage for years [never used].

 

After having to repair several harnesses that had green powdery buildup, bulges in the insulation and stretched an inch or more under tension, and after hearing statements the pierce probes "do no damage 'cause the wires heal themselves", out came my unused set of adapters.

 

I purchased these adapters many years back for that "just in case" event. These are Pamona / Fluke brand adapters which allow the user to adjust the depth of the piercing point into the wire. The adapter is placed on the wire with the screw adjustment all the way out, and you slowly turn the adjustment until the needle probe just pierces the insulation. This feature alone is worth the higher price tag these adapters command.  These adapters also have a much thinner diameter probe, leaving a much smaller indentation than less expensive probes. I figure these would do less damage than almost all other probes on the market.

 

http://www.amazon.com/INSULATION-PIERCING-CLIPS-PACK-OF/dp/B00HB7ETXY/ref=sr_1_15?ie=UTF8&qid=1415180991&sr=8-15&keywords=pomona+piercing+probes

 

Two different types of wire were pierced in effort to prove or disprove the "self healing" statement. All these experiments were performed over two weeks ago while the crickets were chirping. Two + weeks later, I don't see any evidence of self healing on either the marine grade 14 awg wire or the automotive quality 22 awg wire shown in the pics below. Next comes the dunk test in salt water to see if any portion of the pierce has the ability to seal out the environment.

 

 

Results will be posted shortly.

 

 

post-1689-0-25341500-1415181338_thumb.gi

Edited by Save Old Iron
  • Like 4

Share this post


Link to post
Share on other sites

Interesting enough, I stumbled across a few informative posts in magazine articles targeted at the professional troubleshooter in today's automotive arena.

 

Some techs have no qualms about piercing a wire’s insulation any time--or any place on a vehicle. Yes, there are piercing tools that inflict minimal damage to the insulation. Yes, you can treat the pierced insulation with something like nail polish, liquid tape or something similar after the fact.

However, I’m well acquainted with snowy weather, road salt and the impact of both on electrical wiring. I have fixed my share of wires and connections that road splash and salt destroyed. Often, visual inspection suggested that the wire’s insulation was damaged or compromised somehow. Sometimes it takes a while for symptoms to appear. By the time the owner brings the vehicle in for diagnosis, the copper strands inside the damaged insulation have disintegrated into a greenish powder!

Consequently, I don’t pierce a wire’s insulation unless there’s simply no other way to make the voltage measurement. Instead, I backprobe connections wherever possible. I’ve been using the backprobes sold by Automotive Electronics Services (www.aeswave.com) for years. Likely, these are among the most popular ones on the market.

Foreign Service

By Dan Marinucci | October 2012

Motor Magazine.

 

 

and from the supplier of automotive wiring and lighting products

 

 

Water wicking is a term describing how water can travel internally through and along wires due to some of water’s very strong properties. When water seeps into very small cracks and seams

in connectors and wires, it uses adhesion cohesion and surface tension to stick to things.

Through high adhesion, water’s “sticking†property, water will hold to surfaces, just as rain sticks to the surface of clothing (rather than completely running off). It is in this manner that water sticks to the copper in harness wiring well, and gets into the small places between the wires and the insulation. Water’s high cohesion properties cause it to bead up and, and through surface   tension, it will stick to itself, as shown on a newly waxed car. Water that gets pulled into the small

spaces in wiring, between the wire and insulation, drags along more water because it sticks to itself well. The problem escalates when these properties propel the water up the wire far more than the level the connector may have been immersed to begin with. Water can travel great distances by wicking, sometimes causing corrosion along the entire length

of the wire. This is the most damaging form of corrosion because it can be slow and difficult to

detect until a failure has occurred deep in a wire. It can damage the whole wire length, and when the harness eventually fails, the entire length must be replaced.

 

Sometimes corrosion can appear in the middle of the

harness due to a break in the insulation from road

damage, or through the use of a piercing probe. Look

for signs of corrosion or breaks inside the wire.

Using a piercing probe is discouraged, as it leaves a

hole in the wire that can lead to corrosion itself. If

there is evidence that a piercing probe was used in

the past, all holes in the insulation must be sealed.

Road debris can also break the insulation and allow

moisture to wick into the wire. Swelling in the wire

insulation can indicate the presence of corrosion at

a break in the insulation. The corrosion will often

extend beyond the swelling, requiring a larger

segment of the wire to be replaced.

 

 

Dark internal wire indicates signs

of corrosion or moisture, and should be cut further

back until clean bright wire is exposed.

 

 

To begin splicing in a new length of wire, be sure to

cut the new section of wire to be slightly longer than

needed to assure there will be adequate slack.

1. It is important to avoid any damage-prone

methods, such as insulation-displacement clamp

connectors. They tend to create more problems

than they solve in harsh

environments.

Use of these connectors

also causes the insulation to

be displaced or moved out

of the way by a blade that

cuts through the insulation

to make the electrical

connection to the copper

inside. This is a weak mechanical connection, both

mechanically and electrically. The exposed wire

and weak connection also provides an easy target

to corrosives, arcing, and mechanical vibration.

Sealing the connector with tape is also not practical,

because water can wick into holes in the tape. A

fully sealed permanent repair is recommended to

prevent the connection from failing in the future.

 

©2007 All rights reserved. Truck-Lite Co., Inc.

 

 

and the last submission I will make revolves around the following YouTube video. Yes, it is 40 minutes long and troubleshoots a harness problem in a Chevy Impala, but the level of professionalism displayed by this individual is what I would expect from any shop. Give me 2 more individuals like him and I could run every other repair facility out of town. This gentleman goes thru great lengths NOT TO PIERCE THE HARNESS just for convenience sake. Notice, no sensors are randomly swapped out. Notice, customer (possibly you ) will not be charged for wrong guesses on the part of the troubleshooter.

 

If anyone cares about how I think a true professional acts ..... here it is.

 

 

Edited by Save Old Iron
  • Like 3

Share this post


Link to post
Share on other sites

Years ago in my Chevy shop days a Police car was towed in. It had been to a couple of local shops recently and one was a fuel pump change.  sure enough it was a no fuel issue. Fuel pump wasn't running. I check the fuse first and proceed to the fuel pump relay. Relay is working and sending power to the pump. I check at the pump connector and nothing. I follow the 12v feed back to the relay and about half way along the wire "feels ' different. In fact it STRETCHES! The wire had corroded internally in the wire. I check the wire further and find a piercing hole in the wire a ways away from the relay. water had gotten in and found a spot it liked under the LR seat.  

 

Fast forward 10 years. I'm working at a Napa store and a garage calls for a fuel pump for a S-10. Later he calls for a relay. I live near the shop and he calls and asks me if I can stop by because he can't get the truck running. I get there and do the same test, and find the same thing.

 

I had also had 2 cars towed in for no starts where the fusible link was corroded internally after the power feed it was connected to had been pierced somewhere down the line.

  • Like 1

Share this post


Link to post
Share on other sites

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now


  • Recently Browsing   0 members

    No registered users viewing this page.

×