A 4.6/5.4/6.8 2v Modular engine COP ignition coil
Intro:
1991-1997 Town Car and 1992-1997 Crown Victoria and Grand Marquis have a waste-spark ignition system. This was the first all-electronic distributor-less ignition system for the panther platform with it's new 4.6l Modular engine.
The waste-spark EDIS uses two main coil packs, mounted at the front of the engine, with spark plug wires from the packs to each cylinder. Each of these packs contain two primary coils each igniting 2 cylinders/spark plugs.
As the name denotes, because of the paired cylinder firing one of the sparks is 'wasted' on the non-firing cylinder (which is on it's exhaust stroke).
The two coil packs are powered constant w/ ignition, with the primary coils being triggered via ground pulse from the PCM. THere are 4 total ground triggers, one for each coil in each coil pack, and each one for two cylinders.
1998 to current Crown Victoria, Grand Marquis, Town Car, and the '03-'04 Marauder use an ignition system called coil-on/near-plug. This system uses a separate ignition coil for each cylinder, allowing full individual spark control of each cylinder by the power train control module.
The ignition coils are mounted to the intake manifold, directly above each plug and use a small rubber boot and spring to connect to the plug. The electrical connection to the engine harness is a small two pin connector. Voltage is supplied constant w/ ignition, with the ground for each coil being triggered by the PCM.
With some work, we can retrofit the '98+ style COPs to our '91/'92-'97s - but with one main difference. Unlike the factory '98+ system, ours will remain waste-spark EDIS. So, we need to fire two of the new COPs at the same time using the existing PCM ground triggers.
The advantage is a cleaner engine bay appearance and more clearance around the engine.
But, a draw back is the -'97 plug wire/coil pack setup is far more resilient to moisture-induced misfires than the '98+
You won't notice any power increase from this modification, other than being new(er) coils versus old. This is really just for aesthetics and to gain some clearance.
As far as which COPs you should use - I recommend using Genuine OE Motorcraft coils. These are the same for all 4.6/5.4/6.8 modular 2v engines. DG508 is the current Motorcraft part number.
Mounting:
I am starting out with mounting, because there is a catch with this and it may shy many of you from the entire project.
The COPs are designed to bolt to the intake manifold using a single M6x20mm bolt. However, only the 1998+ 4.6l 2v intakes have the provisions/mount for the COPs.
So, if you want to use OEM or aftermarket factory-style COPS you need an intakem manifold with these provisions. For '96-'97, that means a '98-'00 nPI intake manifold. If your manifold has already been replaced for the coolant crossover issue, you're in luck. All the updated aluminum crossover manifolds have the COP provisions - so you're good to go.
'91/'92-'97 have it a little tougher. A complete '96-'97 style intake/EGR/fuel rail conversion to use a '96-'00 style nPi intake w/ COP provisions, and everything entailed with that. That said, it's not practical.
But, you're not completely out of luck. This applies to the '96-'97 guys who are (and want to stick with) their factory non-COP manifolds as well.
A few aftermarket vendors are now selling a 4.6l 2v COP which uses no mounting, it simply locks to the plug and plugs into the same connection as the factory. WeaponX is one of a few companies selling these. So, that would be the easiest way for '92-'95 to go ahead with this conversion without EXTENSIVE modifications.
Electrical:
This is surprisingly simple to wire up.
First off, you want to pick up at least 8 COP connectors of a salvage yard car - or order new pigtails from Ford. Do NOT attempt to use a factory COP harness whole, it won't work, as you will find below.
Basically, what we will be doing is wiring the COPs for the existing coil pack cylinder pairs in SERIES. This will fire both COPs for the corresponding cylinder pair using the existing PCM ground triggers at the coil pack connectors.
Most of you are probably thinking - why in series? Wouldn't it be better in parallel?
Well, actually, you're right. Parallel would be better as then if there is an issue with one COP it won't knock out the other COP it is paired with. Both COPs will also have full power when triggered. But, we cannot wire them like this. The PCM ground triggers cannot support enough amperage to ground BOTH COPs when wired in parallel.
That said, DON'T WIRE THEM IN PARALLEL! Trust me, the car will not start or run if you do so - I tested it myself. You could even damage the PCM by doing so.
So, here's a wiring diagram of how we will wire them in series:
So, on the right side coil pack wiring we see the cylinder 1 and 6 pair wired to the COPs in series. For the diagram, I used a green wire - but you can use whatever color you fancy.
Also on the RH coil is the cylinder 3 and 5 pair, I used blue for the diagram.
On the left coil cylinder 2 and cylinder 8 are show with a yellow wire. Cylinder 4 and 7 with orange.
For all cylinder pairs - in the diagram the coil seeing the hot/B+ side of the series pair has a red wire to the connector's Red/Light Green B+ wire. This is to be wired to the COP connectors "B+" labeled pin, which will have a Red/light green wire if using salvage pigtails.
All of your splices to the COP connector pigtails should be soldered and covered with adhesive-lined heat shrink tubing. The entire harness should be wrapped with wire loom then tapped up with electrical tape.
Splices to the stock coil pack wiring can be soldered for a permanent install - but I recommend using connectors instead so the harness can be removed if needed. Three-pin "Weather-pak" style connectors would be perfect for this.
You can leave the stock coil pack connectors wired in as well if you please. If so, make sure to cover it well to prevent moisture from corroding the terminals.
Take your time assembling the harness for a clean installation. I made mine on a bench, and measured the distance from plug to plug for a factory fit. But you can make it in-car if you prefer.
Make sure to leave PLENTY of slack at the back of the harness, where it crosses over between sides. Also take care routing the harness along the back to keep it away from EGR heat.
Radio Noise capacitors:
Thought I should mention this as well. Mine are still wired in with the stock wiring, which I cut AFTER the splice to the capacitors.
I recommend you retain these to prevent any unwanted electrical noise feedback to the sound system. Since the coil packs will be gone you need to mount them elsewhere. I enlarged the holes on the metal mounting tab for each and mounted them to one of the existing timing cover bosses where the coil pack brackets were on each side, using the same bolts. Works great and keeps them tucked tight to the engine.
Review:
I've logged nearly a thousand miles so far on this conversion, with forced induction, without issue. The engine bay looks much cleaner without all the plug wires.
BTW, make sure to use plenty of dielectric grease on those COP boots - all around the seal to the head and some inside the tip to plug as well.
Picture of my COPs and harness installed on RH side:
Have fun! :biggrin:
Email me at dRock96Marquis@crownvic.net
Page last updated: 7-20-2008