348 Spark plug wire rebuild.

I'd been hearing a small misfire at idle for some time, but it was nothing to be worried about. It became a big deal when the car started to miss at about 3200 rpm consistently. That miss became a bigger miss at idle, and the odd backfire. It didn't matter which combo of things I tried (switching sides with components, etc), I couldn't seem to track it down. Searching threads, I tried replacing the cam phase sensor, I thought I had success when switching sides with the MAFs showed the right side one was failing (it had water in it and they were rebuilt by FIC).

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@chris1866 says "check your plug wires once more". So I took each of them off, and looked again. #7 showed signs of arcing.

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Time for new plug wires....$900!!!! no way they're that special. Search F-chat....

"Anatomy of a spark plug wire" is the best thread I've found so far.
https://www.ferrarichat.com/forum/threads/anatomy-of-a-348-spark-plug-wire.239855/

The ends are sort of special (more on that in a minute), but 7mm copper core plug wire is $1/ft from a shop that will cut to length, you can get a 100 foot roll between 50 and 70 bucks. If you're not concerned with color IMO, if the ends work and are in good shape, just replace the wire as I'll show below. Here we go.

WAIT, you say, ferrari must have used some special shielded RFI wrapped steel mesh reinforced wire right?

NOPE. Here's a dissected cut of one of my Reinshagen FZL2XG wires. It's copper core, core sleeve (proper name?), rubber. That's it. And the cut looks that bad because the rubber is getting flaky, afterall they're 31 years old.

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So what do you do? First, find some 7mm copper core wire. I used O'Reilly Omnispark 7mm silicone jacket (not kidding). PN 9998. Yes, they're grey. I think grey is cool, and there is a car and a half of wire there. Oh, and they're $24.99.

https://www.oreillyauto.com/detail/c/omnispark/omnispark-spark-plug-wire-set/oms0/9998

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Second, get the connectors. Here's where it gets fun. A little more searching turned up the kingsborne links to beru ends, and while the style is slightly different, the dimensions are the same. (taking a chance #1). They're $75 for 100 pcs. I only used 16 of mine, so if you want some, PM me. So for $12/16pcs you can build a set of wires. Our running total is now $36. All that is left is labor. I'll address that next.

 

Labor:

Per the "Anatomy of a spark plug wire thread" Measured resistance at the pencil is about 5k ohms and measured resistance at the coil connector is about 1k Ohms. Get a meter, measure them to see if you have other parts out of spec. The kingsborne BER-VESO116 coil ends are really really really close to perfect. The plug connector is a tougher part to find. There are 5k Ohm ends available, but none are dimensionally the same as OE, but I hadn't looked very hard as my ends all measured correct. I bought a BER-ZLE197 at 5k ohms, and it plugs on and looks good, but does NOT look like it will take the factory boot without modification.

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First step to a rebuild is to take apart the old wire, Per @ernie and the AOSPW thread, twist two turns like you're unscrewing it and then pull. With the ends removed, you'll end up with just a wire with the beru ends on it. My old wire was so stiff, it would hold the plug end up.

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Now, with the ends off and the wire removed, measure the length. I found mine to be 750mm, 745mm, 640mm, and 440mm from longest to shortest. there's a +/- 5mm variance. Wire length isn't a big deal because they don't use resistance wire.

One at a time remove a wire assembly, remove the ends, measure and cut the new length of wire and strip about 7mm off each end. Make a jog in the copper downward as shown, it will help when you crimp.

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Set a beru end in place. The connector is flat across the bottom, so the jog in the wire helps keep strands from getting away. Image Unavailable, Please Login

Use a standard pair of crimpers to make the small crimp.


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I bought and Accel wire crimper meant for a vise to make the big crimp. ($18, but I needed it now, $54 running total)

Load:

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Cover:

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....and in a single swift motion squash it with channel locks. I didn't use a vice because I didn't think a vice would move fast enough for the beru ends. It worked great!

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Reassembly, as they say is the reverse of disassembly. When you push the wire back into place in the ends, you may or may not hear it click. I pushed until I was sure it was seated, then gave it a 1/4 turn to "tighten" the wire in place.

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Repeat 8x more times, and that's how it's done.

sjd

 

Clarification on post 1. The MAF had water in it BEFORE they were rebuilt by FIC, and they work great now. FIC was great to work with, and I can recommend them. Each MAF cost $275, and I had them both done. You have to reset them to 383 ohm when they come back, but that's all. Car runs great.

sjd