View Poll Results: Do you back - probe wiring when doing electrical diagnostics?
Yes, and I don't know if it has caused future problems
1
7.69%
Yes, and it has never caused future problems
7
53.85%
Yes, and it has caused problems
1
7.69%
No, because I believe it will cause future wiring problems
2
15.38%
No, I don't know if it will cause future problems or not
0
0%
No, never had a need to do it
2
15.38%
Voters: 13. You may not vote on this poll
Back Probing Wiring
Thread Starter
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Postmaster
Joined: Jan 2003
Posts: 4,417
Likes: 3
From: Durham, NC
Back Probing Wiring
First, check out this thread on the Ranger Forum:
https://www.ford-trucks.com/forums/5...k-probing.html
There is a technical debate going on, so I thought I would do a poll on what the consensus is on back probing wiring. I think if it is properly done, it isn't
a problem. If you vote "Yes" in the pole, please post what you use to back probe.
https://www.ford-trucks.com/forums/5...k-probing.html
There is a technical debate going on, so I thought I would do a poll on what the consensus is on back probing wiring. I think if it is properly done, it isn't
a problem. If you vote "Yes" in the pole, please post what you use to back probe.
Last edited by Bob Ayers; Aug 6, 2006 at 05:07 PM.
Posting Guru
Joined: Feb 2006
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Likes: 1
Hey Bull Durham(heavy on the bull) I'm your first voter. The reasons are given in the other thread, and I'll not bore the readers by re-posting.
The term "back probing" generally refers to using some device to check the wiring inside a connector or other access. Otherwise, you are simply "probing" if you are just poking holes in wires.
jd
The term "back probing" generally refers to using some device to check the wiring inside a connector or other access. Otherwise, you are simply "probing" if you are just poking holes in wires.
jd
Cargo Master
Joined: Aug 2003
Posts: 3,237
Likes: 3
From: Belleville, Ontario
Holes in wires...
I've been there done that.
At this time, I'm just going to plead Rookie status and politely bow out.
AL.
P.S. ..... Jimdandy.....Your Signature is bang on !!!!!!!!!!!
At this time, I'm just going to plead Rookie status and politely bow out.
AL.
P.S. ..... Jimdandy.....Your Signature is bang on !!!!!!!!!!!
Hotshot
Joined: Dec 2003
Posts: 18,423
Likes: 9
From: iowa
I vote no cause I know for a fact it can and does cause problems. But I am not going to get lured into an aurguement about it, it just will never be done on my vehicles, and if I find it has been I will replace the wiring or make the shop that allowed it to replace the wiring harness.
Last edited by monsterbaby; Aug 6, 2006 at 10:30 PM.
Fleet Owner
Joined: Aug 2005
Posts: 23,667
Likes: 301
From: Easton,Ks
The Ford Shop Manuals say to use a straight pin to poke the wire so I have and no problems yet. But it has been only 20 years ago I did it, come to think of it I did not seal it. I think I will go out and seal it now.
I have had more problems with wires cut open by varmints and fall off at the connectors. I can not recall any falling in two out in the middle unless a varmint ate through it.
I use a breakout box to do most of the checks anymore but when push comes to shove....
I have had more problems with wires cut open by varmints and fall off at the connectors. I can not recall any falling in two out in the middle unless a varmint ate through it.
I use a breakout box to do most of the checks anymore but when push comes to shove....
Lead Driver
Joined: Nov 2002
Posts: 9,557
Likes: 44
From: Concord, NC
When backprobing is done properly, the insulation of the wires is not pierced at all, thus future problems should never be a concern. Proper backprobing means slipping a probe wire along the wire, past the weather seal of a connector to the metal pin inside the connector. The probes on my multimeter are small enough to fit in the back of the connectors, so I just use those. The rubber seal is flexible enough to allow the probes through, and seal right back when I am finished. With EFI, even the slightest bit of corrosion can cause problems (milliamp signals are impacted heavily by even the slightest change in resistance), so I don't pierce the wire insulation with anything.
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Posting Guru
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Originally Posted by EPNCSU2006
When backprobing is done properly, the insulation of the wires is not pierced at all, thus future problems should never be a concern. Proper backprobing means slipping a probe wire along the wire, past the weather seal of a connector to the metal pin inside the connector. The probes on my multimeter are small enough to fit in the back of the connectors, so I just use those. The rubber seal is flexible enough to allow the probes through, and seal right back when I am finished. With EFI, even the slightest bit of corrosion can cause problems (milliamp signals are impacted heavily by even the slightest change in resistance), so I don't pierce the wire insulation with anything.
jd
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Thread Starter
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Postmaster
Joined: Jan 2003
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From: Durham, NC
Originally Posted by EPNCSU2006
When backprobing is done properly, the insulation of the wires is not pierced at all, thus future problems should never be a concern. Proper backprobing means slipping a probe wire along the wire, past the weather seal of a connector to the metal pin inside the connector. The probes on my multimeter are small enough to fit in the back of the connectors, so I just use those. The rubber seal is flexible enough to allow the probes through, and seal right back when I am finished. With EFI, even the slightest bit of corrosion can cause problems (milliamp signals are impacted heavily by even the slightest change in resistance), so I don't pierce the wire insulation with anything.
Therefore, low values of series resistance will not effect their operation.
The signal from the passive sensors (IAT, ECT) use a current source from the PCM, so these sensors are affected by series wiring resistance. The good news, the passive sensors can be tested by measuring their resistance with the connector unplugged.
Last edited by Bob Ayers; Aug 8, 2006 at 05:29 AM.
Lead Driver
Joined: Nov 2002
Posts: 9,557
Likes: 44
From: Concord, NC
The corrosion would have to be quite bad to cause problems, but even with the op-amps and such, there is a small amount of current going through the wiring of the voltage generating sensors. Resistance alters the voltage signal some amount, maybe not much, but the voltage is altered none-the-less. Even if corrosion weren't a problem, why risk it when the connector can be backprobed avoiding piercing the wire altogether?
Thread Starter
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Postmaster
Joined: Jan 2003
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From: Durham, NC
Originally Posted by EPNCSU2006
The corrosion would have to be quite bad to cause problems, but even with the op-amps and such, there is a small amount of current going through the wiring of the voltage generating sensors. Resistance alters the voltage signal some amount, maybe not much, but the voltage is altered none-the-less. Even if corrosion weren't a problem, why risk it when the connector can be backprobed avoiding piercing the wire altogether?
circuit....
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Thevenin, Norton, Boolean, Pythagoren theorem's. I named more than you did, but have nothing to do with nothing.
EGO/HEGO, knock, MAP, BP and others are signal generators.
Spout, PIP signals are in shielded cable.
Troubleshooting these devices suggest "back probing" not probing, and poking holes in them. The difference has been explained.
Because of the invironment in which these devices are used, the mfgr goes to much trouble and expense to protect the sensor connectors and wiring. If it were not necessary, they would not bother.
So, common sense (and some hands on experience) tells me not to damage the connector boots or wiring. jd
EGO/HEGO, knock, MAP, BP and others are signal generators.
Spout, PIP signals are in shielded cable.
Troubleshooting these devices suggest "back probing" not probing, and poking holes in them. The difference has been explained.
Because of the invironment in which these devices are used, the mfgr goes to much trouble and expense to protect the sensor connectors and wiring. If it were not necessary, they would not bother.
So, common sense (and some hands on experience) tells me not to damage the connector boots or wiring.
jd
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Postmaster
Joined: Jan 2003
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From: Durham, NC
Originally Posted by jimdandy
Thevenin, Norton, Boolean, Pythagoren theorem's. I named more than you did, but have nothing to do with nothing.
course, this goes along with your thinking that an automotive ignition system
operates on DC, which somebody else had to correct you on in another thread in this forum........
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Originally Posted by Bob Ayers
You obviously don't have a clue what a Thevinin equivalent circuit is, so I can see why you would think they have nothing to do with nothing....
Of course, this goes along with your thinking that an automotive ignition system operates on DC, which somebody else had to correct you on in another thread in this forum........
I also notice that you did not respond to anything I said in the above post, instead you started your usual personal attacks when things don't go your way.
Give it up, Bob. Poking holes in automobile wiring is not a good thing, as several experienced people have stated, and if it is not a good thing, I'm not going to tell someone to do it to their automobile. One can get in enough trouble doing the right things.
jd