devongarver

So I decided to compile some info about the COP setup on our cars, let me know if there is anything you think I should add or if I made any mistakes. Thanks guys!
C.O.P. General Information:

A Coil On Plug is nothing more than a transformer which steps up voltage to fire the spark plug, that is located directly over top the spark plug. The only real difference between COP and other ignition systems is that each COP coil is mounted directly atop the spark plug so the voltage goes directly to the plug electrodes without having to pass through a distributor or wires. It is a direct connection that delivers the hottest spark possible. Resistor plugs are generally used to suppress EMI. Spark plugs wires are going away for the same reason that distributors went away. Vehicle manufacturers want to reduce costs and improve ignition performance and reliability. Plug wires are an assembly line nuisance, and are often the weak link in distributor-less ignition systems. The plug wires must carry anywhere from 5,000 up to 40,000 or more volts to fire the plugs. This requires heavy insulation plus the ability to suppress electromagnetic interference (EMI). The wires must also be coated with a tough outer jacket to withstand high temperatures in the engine compartment and chemical attack.

As reliable as today's plug wires are, there is always the potential for trouble. Even the toughest insulation can burn if a wire rubs up against a hot exhaust manifold. The connection inside the spark plug boot between the wire and plug terminal can also be damaged if someone jerks on the wire to remove the boot when changing spark plugs. Plug wires can also radiate magnetic fields that may affect nearby sensor wires or other electronic circuits.

Attaching the ignition coils directly to the spark plugs eliminates the need for separate high voltage wires along with their potential for trouble. Eliminating the individual plug wires also eliminates the need for wire looms and heat shields. That is why coil-on-plug ignition systems are being used on a growing number of late model engines.

Getting rid of the plug wires not only saves money, it also improves the durability of the ignition system. No high voltage wires means no voltage leaks and no misfires due to "bad" plug wires. Using individual coils for each spark plug also means the coils have more time between each firing. Increasing the "coil saturation" time (the time the voltage to the coil is on to build up its magnetic field) increases the coil output voltage at high rpm when misfire is most apt to occur under load.


What are common symptoms associated with them failing?

COP problems can include many of the same ailments as other ignition systems such as misfiring, hard starting or a no start. Spark plugs can still be fouled by oil or fuel deposits as well as pre-ignition and detonation. So COP ignition systems are not immune to trouble.

If the crankshaft position sensor fails, the loss of the basic timing signal will prevent the system from generating a spark and the engine will not start or run. A failed driver circuit within the PCM can kill an individual coil and prevent that cylinder from firing. But with COP, an individual coil failure will only cause misfiring in one cylinder.

It is important to remember that ignition misfire can also be caused by other factors such as worn or fouled spark plugs, loose or damaged coil connectors or terminals, dirty fuel injectors, low fuel pressure, intake vacuum leaks, loss of compression in a cylinder, even a tankful of "bad" gas contaminated with water. These other possibilities should all be ruled out before a COP unit is replaced.

The most common trouble codes you may encounter with COP systems on OBD II equipped vehicles are P0300 series codes such as P0301, P0302, etc. that indicate a misfire in a particular cylinder. The important point to remember here is that a general misfire code (P0300) is probably not ignition related but is due to a vacuum leak or fuel delivery problem.

A code that indicates a misfire in a single cylinder (such as P0304), on the other hand, will usually be due to a fouled spark plug, weak coil, dirty or dead fuel injector, or loss of compression (burned vale or leaky head gasket).

If a misfire is due to a bad coil, you should find a coil code that corresponds to the same cylinder (P0351 to P0358). (Not ALWAYS the case as intermittent misfires won't always throw codes)
If a misfire is fuel related, you should also find a code that indicates an open or shorted injector in that cylinder (P0201 to P0208).

A COP engine that cranks but fails to start, in many cases, will often have a problem in the crankshaft position sensor circuit (code P0320). Loss of the camshaft position sensor signal (code P0340) may prevent the PCM from properly synchronizing the fuel injectors, but may still allow the engine to start and run in a limp-in mode.

What are some ways they can fail? / What causes them to fail?

There are a few ways that the COP setup can fail.
The casing which the coil itself is surrounded with will often crack and allow moisture to enter the coil. This is usually due to the 100s of heat cycles the housing and coil have gone through over the lifespan of the vehicle. It can also be onset to an already weakened housing by spraying water on your engine when it has just been run to full operating temperature.

The primary of the coil can also open, causing no output whatsoever. This is usually from nothing more than the many cycles the coil has been through as well as the age itself.
The primary can also become highly resistive if corrosion builds up at the primary side-either on the harness connector itself, or if the housing has been compromised and allowed the coil to be open to the harsh environment of the engine bay.

The coil isn't the only part that can fail, the boot itself may dry rot and crack over time, allowing arcing to occur which in turn will cause a misfire. It will be intermittent making it even harder to diagnose.
The spring inside the boot which sets over the spark plug can also become corroded, causing a poor connection and misfires.

How can i help prevent them from failing?

Preventative maintenance is likely the least used section in any repair manual, but it should be the other way around! Some simple things like keeping the engine bay clean and only cleaning the motor when its cold can make a big difference in the life of your components.

The use of dielectric grease on both the harness connections and the plug connections for each COP setup is crucial to prevent future corrosion.

Frequent check ups on your plug connections and the coil boot can help deter a breakdown on the road, by finding an issue before it becomes bad enough to prevent cylinder firing.

How can you test them to tell if they have failed or are failing?

There are a few ways to test the COP ignition system, however, two of the best ways are not commonly able to be performed by your average shade tree mechanic. These include using an oscilloscope to look at the firing signal itself, as well as testing the coil with a HIPOT or Megger. These two devices are basically a high voltage Ohmmeter used to test break over for devices with a high voltage/low current action. Since most people wont have any of this equipment, there is another method of testing that can be used.

(Contributed by CliffyK 8/1/12)
Using a Multimeter on the resistance setting or an Ohmmeter, you can test a COP to some extent. It is not a surefire method, as the amount of voltage applied with a regular meter is not enough to find errant paths or weaknesses that may easily be found with 15-20 kV. It will however give a good representation of a decidedly bad coil.

The primary winding is just "wound up piece of wire", however it is a longish piece of wire that does have measurable resistance--though many inexpensive multimeters are not capable of accurately measuring such low values.

To measure the primary resistance one should first short the test leads and note the meter's readout which will be the resistance of the test leads. Subtract this value from that observed when testing the COP's primary coil. A good COP should show 0.3Ω to 0.8Ω. Less than that would indicate a shorted primary--though this is something I have never seen "in the field".

Also, there is a connection between the primary and secondary, they are joined at the "ground" end of the coil assembly :



Because of this, and the secondary winding being a very long coil of wire having 4kΩ to 10kΩ resistance, the resistance between the either of the primary terminals will be 4kΩ to 10kΩ as the primary resistance (included when testing between the B+ primary terminal and the COP output) is so small as to be negligible.

So, may I suggest:

You may measure the resistance across the primary coil by putting one lead on each of the COPs primary terminals. This should read between 0.3Ω and 0.8Ω. Should it read more than 0.8Ω to 1.0 Ω, the primary is likely shorted. If it reads in the Mega Ohm range, the coil has likely burned/broken open completely and will certainly cause a misfire.

(note: When reading such low resistance values the resistance of the test leads themselves becomes a component of the meter's readout. Before making the primary coil measurement short (connect together) the test leads and note the meter's display--this is the resistance of the test leads, it should be subtracted from the reading you get when testing he primary.)

You can also measure from either of the primary terminals to the spring in the plug boot. This should read between 4kΩ to 10kΩ. Any less would indicate a shorted secondary, more than 12kΩ to 15kΩ, or infinite resistance, indicates the secondary is open. "

Another method of testing to determine if the issue is in fact a coil, you can do a simple trick. Simply unplug a COP harness connector one at a time and see if the engine runs any differently. If it worsens, it is likely not that coil, move on to the next. If it has no change, it very well could be that coil, and you should test it further with a meter and inspect for cracking or damage.

Where can I get replacements?

Once you have figured out that you need to replace the coils, you have many options to consider when purchasing a new set, or individuals.

Prices range from 85-100$/coil to 85-100$/set of 8! Your local Ford dealer can supply them to you, gladly charging you 85$ each. Many aftermarket companies also offer replacements, and some are just as expensive as the dealership ones, while offering a "high performance" rated product. These coils are offered by the likes of Accel, Screamin Demon, MSD, etc. They promise power gains due to a longer duty cycle or higher voltage or both. This allows you to run a wider plug gap(.065) which will allow more combustion and thus more power. I personally have not tried any of these products and I don't ever intend to, as I feel my money is better spent on other aspects of my vehicle.

*NEW* (contributed by cliffyk)
Nearly all (and perhaps ALL) OEM looking COPs are made by the same company...

It's a company named Micro-Tech, they make the Ford OEM coils, and Granatelli's (that's on there website), and I know for a fact Accel's. I could likely buy some made to my specs, with my name on them if I bought enough.

The way that aftermarket coils create a stronger spark is to reduce the number of turns in the primary and use heavier wire--this reduces the impedance of the primary causing it to draw more power and thereby more fully saturate the core. When the core field collapses this creates a potential for a higher powered spark.

It also make the primaries more prone to failure (I lost 3 Accel COPs in less than 30k miles and am now running my OEM units which I had saved)--and if pushed too far can overload the control transistors in the PCM and fry them...


Now, for most of you out there like myself, A good compromise of price and quality is the way to go. For this, I turn to smaller corporations who deal through eBay and do not have a retail location. This saves them tons of money allowing them to pass on the discount to the consumer-US! I have bought multiple sets for 80-90$ with no issues and received a quality product. The choice is up to you, but my personal recommendation is to check out sources online before you hump it up to your dealership and fork over hard earned cash for the same product. Below is a list of common model numbers that can be used for replacements for the 4.6 motors.

Compatible Model Numbers:
DG 508
DG 457
DG 472
DG 491
F523
F7TU-12A366AB
F7TU-2A366BA
F7TZ012029BA
F7TZ-1029CC
F7TZ-1029CC
F7TZ-12029AB
FZTZ-12029CA
I2LU-12A388-AA
IL-2Z-12029-AA

NEW INFO**** Numbers for 4V motors!!!

Ford F7LZ-12029-AC, F7LZ-12029-AA, F7LZ-12029-AD, 4L7Z-12029-AA,
UF-191 UF 191 UF191 C-1141 E567C C1141E567C
1F3Z-12029-AA 1F3Z 12029 AA 1F3Z12029AA
2C6Z-12029AA 2C6Z12029AA 2C6U-12A366AA 2C6U12A366AA
C1808C F7LU-12A366-AD F7LU 12A366 AD F7LU12A366AD Motorcraft DG-478 DG-492

DG-512







How do I replace them?

Once you have attained you replacement COPs you may want to make sure you have all your ducks in a row before installation. Be sure you have checked ALL of your spark plugs first and purchased a replacement set if necessary. Make sure you have some dielectric grease on hand as well as a 1/4 drive socket set with wobble ends/flexible extensions.

You do NOT have to loosen or remove the fuel rails to change the plugs or the COPs. To remove the old COP simply unplug the harness, remove the retaining bolt holding the housing of the COP in place, then give the COP a bit of a turn/wiggle and it should pop right out. Replace the plug if you have decided to do so at this time, then prepare you new COP for installation by applying a small amount of dielectric grease to the inside of the spring and the lip of the boot to help it slide on easier and prevent it from sticking later. Align the new COP over the plug and push down firmly until it is seated onto the plug. Reinstall the bolt, connect the harness, and move on to the next. Be careful not to over tighten as it is easy to crack the housing. All of them can be done with just a ratchet and flexible extensions, but the back ones can be tricky and it is sometimes easier with a small ratcheting wrench.



Useful Links/Sources


https://mustangforums.com/forum/4-6-m...ting-cops.html

https://mustangforums.com/forum/4-6-m...-no-codes.html

http://cgi.ebay.com/ebaymotors/ws/eB...m=110368136118

http://www.aa1car.com/library/copign.htm

http://www.asashop.org/autoinc/feb2003/mech.htm

http://www.micro-tech-auto.com/mt/Ford_COP_Assy.html *NEW* manufacturer of OEM COPs

http://www.weaponxperformance.com/te...CHNICAL_V1.pdf *NEW*

http://www.weaponxperformance.com/xcopinfo.jpg *NEW*

http://www.weaponxperformance.com/te...ls/JBAdyno.jpg *NEW*

http://www.weaponxperformance.com/ *NEW*

devongarver

Big thanks to cliffyk for his contributions to recent threads on this topic!

ShinobiOfLegends

huh, that looks like a page in one of my text books...

also, did cliffy ever find out if the WeaponX COPs were actually worth the money and if they were actually that different from the stock and stock-style COPs?

devongarver

Huh, thats funny i dont remember writing your text book...

Ummm well i dunno, why don't you pm him? I will look into it myself though and get back to you.


EDIT: i just read a lot on their website, im adding a few links the sticky, check them out. Seems they are a COMPLETELY different design and may be worth a look.

cliffyk

I have not yet gotten a set of them to test (I'm working on it)--as for "worth it", probably not unless you are running BIG compression or f/i at more than 12-15 psi.

The OEM COPs have more than enough "testicular fortitude" to fire anything n/a or moderately boosted--unless you toast an OEM cop--which is rare, Ford says over 50% of the COPs returned as warranty replacements have nothing wrong with them--and need a less expensive replacement there's nothing to be had from "OEM look" after market COPs...

Sxynerd

I love you guys! After 20 minutes of pondering what Cliff said in the other thread (and I'm not a 12v dummy) I finally finished downloading and processing in my Brain Housing Group then I tested my suspected COP and the given result was:
1. My $400 Fluke pisses me off.
2. My $40 HF Cen-tech is only worth being a Tire Chuck
3. And swapping the COP boot was my solution, lol

mustangman03

but when u use the ford tester which is the vss used with the ids most of your coils will test bad even when they are good but if u have a missing cylinder just swap the coil around to another cylinder and see if the miss follows the coil. thats what i do a whole lot faster than hooking up the tester.

devongarver

Im not sure i understand how your response is relating to cliffyk's statement. What is a vss? or ids?

Side note: Swapping coils is something i mentioned above lol

cliffyk

IDS (Integrated Diagnostic System) is the latest software that accompanies the VCM/VMM (Vehicle Communications Module/Vehicle Measurement Module) OBD2 interface tools.

Other than Vehicle Speed Sensor I don't know what VSS is, it may be an earlier version of the VMM?

I have the VCM and IDS software, it wasn't cheap however it has paid for itself at least twice over...

ShinobiOfLegends

I've gotten to use it one time. and holy crap was it amazing (Not to mention EXPENSIVE). however, a cheaper alternative for me is using AutoTap and a scope... however, i should add that i can't change any tables or values, just view them...