2001 Expl 5.0 miss under a load

[koda2000]

About a month ago I notice a slight miss when climbing a steep hill near my house in high gear. I was waiting for it to throw a CEL but it never did. I had replaced my spark plugs about 20k ago with Autolite double platinum's so I didn't think that was the issue. The previous owner had his mechanic replace the plug wires (with Motorcraft brand wires) at some point in the not too distant past, so that didn't immediately jump out at me. Upon examination I noticed that the replacement plug wires were routed in the easiest way possible for the mechanic, rather than using the factory wire retainer clip locations and wire routing. I know this because I replaced the OE plug wires on my daughter's '00 5.0L Mountaineer last spring and the OE routing was a pain to duplicate. Plus opening the wire retainer clips without knowing their secrets is also a joy.

Today was sunny and 78 degrees in GA (gotta love that) so I decided I'd at least get one side rewired and install new plugs. I decided to begin with the driver's side, as those plugs take a beating with the wasted-spark. The plugs looked fine, but as I'd bought a set of Autolite double platinum's off RA (which included a $16 rebate) I decided to install new plugs and a new set of plug wires.

It was a pain trying to figure out which wire would work best with the OE routing because the PO's mechanic just put any wire that would reach where ever. I found I was missing 1 of the OE wire retainer clips for the driver's side, but the majority of them were there just not used where they belonged. I finally got the new wires routed to my satisfaction and took it for a test drive. No more miss. I'll wait until another nice day before I do the passenger side.

If any of you "junk yard dogs" (you know who you are) happen to see a Ford 5.0L with its original plastic wire clips on the driver's side valve cover (they snap onto a small post which is welded to the top of the VC and there are 2 used on the driver's VC) I need at lease one. These retainer clips have space for 3 wires, but are only used to hold 2. Note: You'll probably need to cut the plug wires as opening these clips with the wires in the vehicle is nearly impossible. These 2 clips need to be snapped off from the side, not pulled.

As I haven't attempted the passenger side wires yet so I don't know what I might be missing there. There are several different wire retainers used on this vehicle/engine...

- The 2 used on top of the driver's side VC used for cylinders 7 and 8.

- 2 that slides over posts on the two passenger side VC bolts. This clip holds just one wire and is used under the intake plenum and the rear of the VC for the #4 plug wire. They fit onto 2 special bolts used on the valve cover.

- Ones that holds 2 wires and the clip has a push-in style Xmass tree clip which fit into special brackets used on both sides of the front of the engine. These are used to hold the plug wires for cylinders 5 & 6 and cylinders 1 & 2.

- Basic clips that hold 4 wires, float and just snap closed (there are a few of those used near the coil pack on both sides)

- I think there's one 3-wire clip used on the passenger side and it holds the wires for cylinder 1, 2, and 3.

Without using the factory wire retainer clips (and routing the wires properly) you run the risk of burning a $90 wire set on the exhaust manifolds or from rubbing on various things under the hood.

 

[tripog]

i haven't had the original wire holders for a long time now and never had an issue with missing because of lazy spark plug wire routing. i think you have other issues or extremely poor quality wires.

 

[koda2000]

i haven't had the original wire holders for a long time now and never had an issue with missing because of lazy spark plug wire routing. i think you have other issues or extremely poor quality wires.

I don't think so. They were the second set of Motorcraft wires installed in under 200,000 miles and the plugs were quite new. My daughter's Mountaineer's factory wires had 240,000 miles on them and were probably still okay.

Anyway, replacing the plugs and wires fixed my problem and I like things to be installed the way the manufacturer intended them to be. Being sloppy will always bite you in the ass eventually. I found plug wires touching the exhaust manifold, which is never a good thing.

 

[tripog]

these aren't super high performance engines, if wires are affecting the other wires like that there is a bigger issue. your problem may be solved for the time but i wouldn't blame the wire route.

fwiw i have run some cheap rock auto wires for about 6 years now just routed over and on each other every which way. i changed out the plugs and wires when i got the vehicle because it had a bit of a miss preventing the torque converter from locking up. the valve covers were too rusty so those wire holders were the first to rust off obviously. routing makes things look nice but on a basic stock engine like the ford 5.0 unless the wires are faulty the routing of them isnt going to cause a miss

 

[koda2000]

I've been working on engines probably longer than you've been alive and I think I can diagnosis a spark related miss when I feel one.

As far as plug wire quality and routing, you are welcome to do it anyway you want. There have been many cases of plug wires burning on exhaust headers reported here over the years.

 

[Mbrooks420]

Routing surely can matter, as I’m sure you know. The extreme high voltage of the wires can certainly cause induction issues. I also had an issue with my first Mounty having a melted wire due to someone half assing the wire routing.

I’m sure you also know that Motorcraft wires are pretty excellent. I’ve never had issues with 100k on the factory wires. Typically people damage them by yanking on them.

I’m trying to get to the pick an pull next week, I’ll see if I can grab some clips.

 

[shucker1]

Watching.

 

[koda2000]

Routing surely can matter, as I’m sure you know. The extreme high voltage of the wires can certainly cause induction issues. I also had an issue with my first Mounty having a melted wire due to someone half assing the wire routing.

I’m sure you also know that Motorcraft wires are pretty excellent. I’ve never had issues with 100k on the factory wires. Typically people damage them by yanking on them.

I’m trying to get to the pick an pull next week, I’ll see if I can grab some clips.

Oh, I forgot to mention, I found the clip I needed for the driver's side valve cover used on the passenger side wires and moved it back where it belonged. The passenger side clips were used on the passenger side, just not where they belonged, so I'm good on clips. Thanks for offering though.

It's a shame the PO's mechanic ruined a new set of Motorcraft wires by his routing, but you never know what you're gonna find on a used vehicle. I used to restore 50's and 60's classic cars and you really find messed up electrical stuff when you dig into them.

I don't know if you got to see the pic of what I actually found after examining the plug wires I removed from my Explorer (my post got deleted by the moderator) but below is what I found from a wire that had been sitting on the exhaust header (it's a little blurry, but it was burned through to the core).

Note: For those who disagree that using the factory plug wire routing is necessary, I'm not saying everyone needs to do it this way (it's just the way I do things) but however you chose to route your plug wires keep them away from moving parts and the exhaust headers. It's just logical.