7.3L spark plug/coil wire failure

stufarmer said:
Hey Red, .. this topic has gotten a little confusing. Since the upgraded "RV" Plug Wires appears to accommodate a Spark Plug with a larger sized Porcelain, what's your opinion on installing a new set of "RV" Spark Plugs along with the larger porcelain Spark Plug. Everything then would be sized appropriate.
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I guess my only thoughts on this are what's the design purpose of the larger diameter porcelain insulator? Plugs usually have a purpose for each characteristic designed in. Heat retention/dissipation are just a couple reasons for insulator length and size, among other reasons. I have a couple of these wires installed on the original plugs no issue. Pulled the camper to Tenn. and back and then a week later went to Alabama and back no issues. Actually I wasn't aware of a larger diameter plug that was specified for our engine.
 
Well I finally got bit by the plug wires. Was towing my toy hauler on Tuesday, truck shuttered and died. Restarted and had zero CEL’s. Pulled codes and nothing was in there. A Ford tech was able to hop in through the connected services and see that the engine had a #1 cylinder misfire. The truck drove fine for another 120 miles or so and I swapped wires out for the Ultima Select wires from O’reilly’s.

Found Cylinder one to have disintegrated the inner wire right above the metal clamp. From reading through this, it looks like I had “B” wires on.

Truck has just shy of 30k with about 1/3 of that being towing miles with our toy hauler through the Colorado Rockies.
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Flourman said:
Well I finally got bit by the plug wires. Was towing my toy hauler on Tuesday, truck shuttered and died. Restarted and had zero CEL’s. Pulled codes and nothing was in there. A Ford tech was able to hop in through the connected services and see that the engine had a #1 cylinder misfire. The truck drove fine for another 120 miles or so and I swapped wires out for the Ultima Select wires from O’reilly’s.

Found Cylinder one to have disintegrated the inner wire right above the metal clamp. From reading through this, it looks like I had “B” wires on.

Truck has just shy of 30k with about 1/3 of that being towing miles with our toy hauler through the Colorado Rockies. View attachment 124788View attachment 124789View attachment 124790View attachment 124791
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Well looking for the positive side of things at least you were able to find the cause of the truck dying. That could've been a bit unnerving not knowing if it was going to rear its head again...
 
KILLAZILLA said:
Your kidding? They have a "D" version now...
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Yes, 4th version.
WR6163- 1st gen (A wires)
WR6164- 2nd gen (B wires)
WR6167- “3rd gen” (C wires) I don’t know that these were ever installed from the factory on the super duty’s. These were on the motorhome chassis 7.3’s. A few of us swapped over to these including myself.
WR6170- 4th gen (D wires)
A quick search on rock auto for my ‘22 and it only shows the new D wires.

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Tucsontremor said:
Yes, 4th version.
WR6163- 1st gen (A wires)
WR6164- 2nd gen (B wires)
WR6167- “3rd gen” (C wires) I don’t know that these were ever installed from the factory on the super duty’s. These were on the motorhome chassis 7.3’s. A few of us swapped over to these including myself.
WR6170- 4th gen (D wires)
A quick search on rock auto for my ‘22 and it only shows the new D wires.

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Wonder what the changed or upgraded from previous versions
 
KILLAZILLA said:
Wonder what the changed or upgraded from previous versions
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One change I am aware of is more positive retention between the plug and wire. Apparently one of the issues has been intermittent contact...
 
Modman said:
One change I am aware of is more positive retention between the plug and wire. Apparently one of the issues has been intermittent contact...
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Makes sense as when I installed the A and C wires I didn't feel like there was a definitive snap-on and really had to push and pull on them to double check that they were fully on and wouldn't pop loose.
 
Well, it happened today. Misfire on cylinder 2. Luckily, thanks to this forum I was carrying 8 new WR6167 / LC3Z-12886-C wires with me, as well as a reader. Swapped out the single wire on the side of the road, code cleared. 26,870 miles. I'll probably change the other 7 when its not 102 degrees and the exhaust manifold isn't red hot. The old wire broke as I took it out - the rubber insulator was completely deteriorated and crumbly under the metal shield. I would highly recommend that everyone with a 7.3 carry an OBD reader and at least one extra wire with them, or 8... :rolleyes:

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TexanTremor said:
Well, it happened today. Misfire on cylinder 2. Luckily, thanks to this forum I was carrying 8 new WR6167 / LC3Z-12886-C wires with me, as well as a reader. Swapped out the single wire on the side of the road, code cleared. 26,870 miles. I'll probably change the other 7 when its not 102 degrees and the exhaust manifold isn't red hot. The old wire broke as I took it out - the rubber insulator was completely deteriorated and crumbly under the metal shield. I would highly recommend that everyone with a 7.3 carry an OBD reader and at least one extra wire with them, or 8... :rolleyes:
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I've been running a set of suffix C wires now for about 30,000 miles. I put six of the original wires under the rear seat as spares to get home. My code reader didi not show me a problem on a particular cylinder. Do I need a more up to date reader? Or one more compatible with the current vehicle code? What should I get?
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That's the reader I'm using too. It obviously detailed the correct cylinder. I saw that my Ford pass app also showed a "service engine soon" notification - It even noted the problem as a misfire!

I will be putting the old wires under the seat for emergency spares as well.
 
 
It's funny how this problem can appear to come and go, as well as making the engine run terrible when it happens. I have some theories on this.

First, the wires fail because of a poor connection between the carbon impregnated string conductor and the spark plug clip. I took mine apart and thst is what I found. As the bad connection allows the spark to burn away the string, the gap eventually becomes so great that the spark cannot jump the gap, and a misfire happens. But once cool, there is less resistance and it can run normally, for a while. Also, the engine is tuned to run very lean and is constantly being monitored and the mixture adjusted. When there is a misfire, raw gas goes out that cylinder's exhaust port and is read by the oxygen sensor. The computer leans the mixture to compensate and other cylinders drop out because the mixture is too lean to run correctly. Bottom line: The loss of one cylinder can seriously affect the entire engine. Strangely, I discovered that adding a heavy dose of gas treatment temporarily cures the problem and the engine runs good for a while. This is a good trick for getting home if you don't have any spare wires. I babied mine along for 1,500 miles this way while I decided on the best wire set, confirmed what the problem was and got the parts in. I tried to order the wires at my dealer but the parts guy argued with me that I did not need new wires. I tuned him up on the subject and then ordered suffix C wires from Rockauto for 1/3 the price. BTW, in a pinch and stopped somewhere far from a parts store, I see no reason why a temporary wire could not be fashioned from a coat hangar, bailing wire, or piece of copper wire from a piece of romex house wire. Bend one end into a U and fit it into the coil. Wrap the other end around the plug tip and keep the wire as far from the manifold as possible. Drive on. I spend a lot of time out in the desert and way up in the mountains and I have no intention of walking out if I can help it. But as far as the wires are concerned, I have six extras with me.
 
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Raspy said:
When there is a misfire, raw gas goes out that cylinder's exhaust port and is read by the oxygen sensor. The computer leans the mixture to compensate and other cylinders drop out because the mixture is too lean to run correctly.
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I think you are spot on regarding what is happening to the plug wires. The first statement in the quoted text above also is correct. There is a misfire monitor strategy, however, that will determine the cylinder in question based on the timing of the rich mixture (in this case) at the oxygen sensor. There is no need to adjust all cylinders unless there is a "global" issue. In that case an engine protect strategy can be employed which is a relatively rich mixture, not lean... the emissions laws allow for this as a last resort so that engine replacements don't become an unintended result. The logic/capability of a modern engine control system is really phenomenal. Both hardware and software come into play here...
 
Modman said:
I think you are spot on regarding what is happening to the plug wires. The first statement in the quoted text above also is correct. There is a misfire monitor strategy, however, that will determine the cylinder in question based on the timing of the rich mixture (in this case) at the oxygen sensor. There is no need to adjust all cylinders unless there is a "global" issue. In that case an engine protect strategy can be employed which is a relatively rich mixture, not lean... the emissions laws allow for this as a last resort so that engine replacements don't become an unintended result. The logic/capability of a modern engine control system is really phenomenal. Both hardware and software come into play here...
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IMHO, the MAIN issue is engine bay heat as I've been through 3 battery "leaking" cap replaced from I believe a engine bay heat issue. The spark wire just get exposed to more extreme heat being directed near the exhaust headers. C wires seem to be holding up this far...FINGERS CROSSED
 
KILLAZILLA said:
IMHO, the MAIN issue is engine bay heat as I've been through 3 battery "leaking" cap replaced from I believe a engine bay heat issue. The spark wire just get exposed to more extreme heat being directed near the exhaust headers. C wires seem to be holding up this far...FINGERS CROSSED
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I'm wondering if the heat is the reason Ford went with those giant side badges on the 23MY. 🤷 It would make sense
 
marine_wi said:
I'm wondering if the heat is the reason Ford went with those giant side badges on the 23MY. 🤷 It would make sense
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Yep. Of course they did specifically for that exact reason. Kinda UGLY...but, functional I suppose??? Time will tell
 
If anything all our trucks will eventually have the "BEST" wires "prematurely" replaced in some cases and let's ALL just do the damn plugs as well while we're down there...
 
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