8.1 spark plug wires

[TAN]

I would like to no the number of the spark plug wires that burn out the most. I would also like to no the firing order. Thank you.

[DriVer]

Quote:

Originally Posted by TAN I would like to no the number of the spark plug wires that burn out the most. I would also like to no the firing order. Thank you.

TAN, The number of spark plug wires that may burn out due to body manufacturer configuration differ. There isn't a set pattern.

The plug wires that have typically been seen as failing for various reasons on the left side of the engine from the drivers seat are the number 5 & 7. On the passenger side one might see the 6 & 8 wires failing however there has been no stead fast rule that the wires are going to fail. I went many miles with original wires with no burnouts.

Workhorse developed a vent kit that applies the smallest amount of air, passively, that has been proven effective in reducing the temperature of the plug boots to the point where burn-out have been remedied.

The 8.1L engine's firing order is: 1-8-7-2-6-5-4-3. I was just wondering; Now that you know the firing order, how does that help you manage this issue?

The 8.1L engine's firing order is different than the 1-8-4-3-6-5-7-2 firing order that we have previously seen on GM engines as they claim that the revised firing order allows the engine to operate more smoothly.

The engine's spark plug configuration begins at the left front where the #1 plug is located followed by the 3, 5, & 7. On the right side of the engine you will see the #2 in front followed by the 4, 6, & 8.

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[TAN]

Thanks Driver. I wanted to know the firing order so I would know what wire was the one that burnt out when I would read about some one on this site having burnt wires. Also thinking it would help me know what wires to look at on mine. I had my wires replaced at 25000 miles and the number 7 wire would fall off. I rotated number 5 and 7 and the problam seemed to go away. Thanks again.

[Paul T]

Now that DriVer has explained the plug numbering system I’ll add two cents. Back at 10,000 miles I had the dreaded engine miss problem and plugs 5 and 8 were replaced under warrantee. The shop doing the work said number 5 had come apart and burnt however, the documentation made no comment on number 8. I recently experienced the same engine miss problems near 25,000 miles and being a bit cheap thought I’d just replace the wires myself. After three weeks thinking about it, buying a set of Taylor Extremes, reading hints from other on this forum and giving up at least twice I finally have my new plug wires in.



But now I have a question DriVer. Should I have reinstalled the metal shields that were on the original wires underneath the new fiber heat shields? I left them off thinking the flexible fiber heat shields that came installed on the Taylors were designed as replacements.



After much pondering as to how to gain access to the wires I attacked the right bank first. That was so easy it gave me the courage to attack the left bank of wires. The second from the aft plug wire on the driver’s side appeared loose and burnt. So, according to DRIVER, that was my number 5 wire, (the same one as was described as bunt back at 10,000 miles). In my particular coach it is also the wire with the least amount of free air space around it.

Access to the wires on the passenger side was very easy and the pictures here basically portray my entry to gain access. Once under the RV a bit of twisting to get on ones knees on the passenger side was required but from that position access to the right bank of plug wires was very easy and removal an installation was a non event. Using the suggestion of others here I removed to top of each wire first then rotated the boot around the plug itself while pulling at the same time. I also only did one wire at a time so if I had a major problem I assumed I could get the engine started and drive the beast to a real shop.

Replacing the wires on the driver’s side required a bit more body manipulation than the passenger side because I have a hydraulic pump right where you would want to get on your knees. Thus, I slid further aft on my back and was able to gain access sitting on my behind just aft of the driver’s side tire and just forward of the jack/slide hydraulic pump installation. Working on the driver’s side was a lot more difficult than the passenger side but if a crippled old man can do it I bet some of the rest of you can. I had the most trouble getting the top of wire 1 plugged in primarily because I could barely reach it with my hand from my chosen position.

If I only have to do this every 10 to 15 thousand miles I’ll live without installing the additional airflow systems described so thoroughly elsewhere. I’m hoping that just using the Taylor Extremes will avoid future problems. And, the next time I have a engine miss, I just might use one of my old wires to replace number 5 wire only.

Sorry about the Xs, can't figure out how to post a photo.

[DriVer]

Quote:

Originally Posted by Paul T But now I have a question DriVer. Should I have reinstalled the metal shields that were on the original wires underneath the new fiber heat shields? I left them off thinking the flexible fiber heat shields that came installed on the Taylors were designed as replacements.

Paul T., According to Taylor, do not reinstall the plug shields.

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[JC2]

Quote:

Originally Posted by DriVer Paul T., According to Taylor, do not reinstall the plug shields. - ■ -

No respect to you DriVer but:

Do you agree with this Oemy?

[DriVer]

Quote:

Originally Posted by JC2 No respect to you DriVer but ...

JC2, That's me - I get no respect!

[oemtech]

I have had mine on since I put the Taylor TV 50's and the wire shields some 3 year's ago. I will leave that up to the user.

I guess would need to know why Taylor recommends not to reinstall them. Better yet why did GM install them in the first place?

Mike you are going against what GM/Whorkhorse installed?

[DriVer]

Quote:

Originally Posted by oemtech Mike you are going against what GM/Workhorse installed?

Dale, GM didn't install Taylors. Check with Brazels - their recommendation is per Taylor to delete the spark plug shield when using "their" product, the #99615.

Now if I'm using OE Delco wires, I'm putting the shields on.

[JC2]

Quote:

Originally Posted by DriVer Dale, GM didn't install Taylors. Check with Brazels - their recommendation is per Taylor to delete the spark plug shield when using "their" product, the #99615. Now if I'm using OE Delco wires, I'm putting the shields on.

Now that we've got that clarified.

[TandW]

5 & 7 were my troubling plugs, with the wires either vibrating or blowing off. Never had a "burnt" wire, instead having those that won't come off the plug before leaving the ferrule behind and decoring the fine wire core of the wire itself. I chose to install wire looms, even though the short length of the wire makes this look ridiculous. But after some 60k miles not another wire has come off a plug. I service the plugs from the doghouse. Good luck!!

[oemtech]

Quote:

Originally Posted by DriVer Dale, GM didn't install Taylors. :

That is fairly obvious.

But, Taylor and the OEM wires share the same plug boot. So, why did GM install them and Taylor says not use them on their wires?

OBTW - I sent Taylor an Email asking for an explanation.

[DriVer]

Quote:

Originally Posted by oemtech OBTW - I sent Taylor an Email asking for an explanation.

Dale, Let me know what they said ...

I don't believe the plug boots are the same and I can't tell by the material used since I don't have an OE wire at the moment however where the Taylor wire fits to the boot, it's much wider to accommodate the Blue Spiro wire, so it is different. Exactly how different all the way down to the material would be interesting to find out.



I think the reason as to why to remove the shields may be some how related to heat soak. In evidence here is a severely deteriorated plug boot which is melted into the side of the shield. The other 7 wires did not exhibit this type of severe damage. This evidence provided, it was related to me by Brazels that the shields should have not restored. The inside wrapper presented black in color which is visible in the full size shot.

A miss developed however there was no evidence that the wire burned and separated at the connection point because I was unable to pull the boot away from the wire as is typically seen in those types of failures with OE wires. I have found that OE wires may separate or may be found dangling having burned out at the boot. As you know it is a rare day when as set of OE wires can be removed without at least breaking one. I have not had that type of problem with the Taylors due to the better materials used and more robust wire.



The #7 plug seen here, was having some severe issues in firing properly. In my estimation, The spark was jumping from the boot to the shield once the insulator broke down. The other 7 plug's insulators were much lighter in color.

I'm going to run without shields for the moment and see how that works out. This issue was resolved by installing a new set of plugs and replacing the 1 wire. The engine is firing on all eight, no misses no drops no errors on my WOT test drive yesterday.

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[TandW]

Driver, you just mentioned driving WOT. I take that to mean Wide Open Throttle. Surely you know that if your wires are less than 100% or if your plugs are worn or overgapped the high energy spark will not be produced at the plug tip. It will escape via the weakest point in the secondary ignition wiring and that my friend is where heat is highest.This is why we are seeing wires that are "burnt" at the plug. The high heat supports plasma-type conditions where the spark has differentiated into many different paths. One might think of a root ball of a tree. You must have heard of Misfire Under Load. And anyway, what's this business about driving around WOT. Is this not abuse? Pedal to the metal is for rockabillies, not for something you want to keep out of the shop!! With all due respect, Good luck!!