Active LVC Member
- Sep 17, 2012
- Reaction score
Only been on these forums for 6-7 months, But i understand everyone's frustration with constant coil questions, or "misfire" questions, or "what can i do to upgrade my coils?"
Being an Electrical Technician with Aviation Turbine background training, I know a thing or two about Ignition Systems. Being a GenI LS8 owner, I can tell you pretty much any symptom, because chances are good I've had it.
Some of these are MY personal opinions as far as brands, and experience. Others may vary.
I want all LVC members to read through this carefully, and feel free to "politely" correct me, or provide feedback. Lengthy Threads are hard on the brain, and this write up took a VERY long time, and a LOT of thought.
starting things off...
The Typical Newbie LS owners question: "Had a misfire on cylinder 2, replaced the coil, now i have a misfire on 3, and 2 again! Why?"
BEFORE YOU EVEN LAY THAT 7MM SOCKET ON THOSE COVERS, DIAGNOSE IT!
see - "Diagnosing LS Coil Issues" below.
and before you ask about your new "harsh shift" or transmission problems, FIX your misfire, and reset your ECM! (unhook battery for a while)
Couple Rules for Coils on the LS. Both Generations, Both Engines (V6-V8)
1. Replace 1 Coil? - REPLACE THEM ALL - Trust me, and any other member here. You own a "Luxury" car. You've gotta pay the"Luxury"price.
2. Replacing Coils? REPLACE ALL THE PLUGS TOO.
- new coil + old plug = bad coil on each involved cylinder in most cases. usually about 2,000 miles or less. (more resistance on the coil) resistance = heat!
- old coil + new plug = bad coil on each involved cylinder in most cases. usually about 2,000 miles or less.
3.If its not broke, don't fix it. In other words, If its running like a 4.6 Mustang, and getting 23+ MPG.... LEAVE IT ALONE.
4. If it is broke, diagnose and FIX IT!! Misfires, rough idles, emission codes, and bad gas mileage aren't only killing your street reputation, they are killing your converters, and emission components due to unburned fuel!
5. DON'T OVER GAP your plugs. Most call for .35-.44in of gap. I WOULD RECOMMEND .39in or less!
longer distance gap = more voltage required to arc (resistance)
more voltage being used = higher coil temps
higher coil temps = premature failure and a quarter in the swear jar.
6. Take your time. plan ahead. buy a case, or a carton of cigs, pick a night that you have enough time. buy everything you need. even if you have to make 5 trips to the local Auto parts. no shortcuts!
you will need:
A.) 8 new plugs of your preference. I've experimented with them all. all arguments aside, a plug is a plug. I Prefer NGK Iriduim's (BKR5EIX) **for V8** or Motorcraft (SP468) **see "Coil Design, Features, & Aftermarket Options below**
B.) 8 new Coils - Most Member's prefer OEM's (DG529) **GENIV8** I've Experimented with BWD, Duralast, And Masterpro. **see "Coil Design, Features, & Aftermarket Options below**
C.) Spark Plug Gapper (if you don't have one)
D.) Spark Plug Boot Grease - Dielectric, Silicon Grease, Caliper Grease, whatever you would like to call it. Don't be scared to buy two tubes. (it's cheap) - **see "Preventative Coil Measures" below.**
E.) Swivel Sockets, 7mm End Wrench, Extensions, 7mm Deep-well & Shallow sockets. As well as a 5/8 SPARK PLUG SOCKET for easy removal. && let's not forget patience.
got the rules, got the parts and tools?
here's a post on step by steps.
V8 - http://www.lincolnvscadillac.com/tec...gnitionCoilV8/
V6 - http://www.lincolnvscadillac.com/tec...onCoil00-02V6/
V8 - http://www.lincolnvscadillac.com/tec...S/SparkPlugV8/
V6 - http://www.lincolnvscadillac.com/tec...rkPlug00-02V6/
Diagnosing LS Coil Issues
based on experience, previous threads, and some recalls.
Almost every LS owner who buys used hears the same story 7/10 times..
"yeah, i had the coils changed about 3,000 miles ago."
and most new owners have no idea the history behind these cars and their coil problems. Coil problems almost always effect Transmission Operation/Shift Curves!
However, "Coils" aren't always the culprit. Yes, they are the reason for your headaches, but there is ALWAYS a reason why the coils failed. don't always blame the poor coil manufacturers. a lot of times, it was the installers fault. either lack of attention/diagnosis, or improper prevention procedures.
Reasons LS's have problems with Coils, and why Coils tend to fail:
1. Old or "burned up" Coils - If you have over 100,000mi on original coils your doing well.. and your LS deserves new coils. Inspect, and replace.
2. Leaking Valve Cover Gaskets - If your plug/plug wells look like mine did:
Chances are 100% you need VCG's.
Unofficial (to my knowledge) Recall. Some have gotten their gaskets replaced under warranty. Some without warranty, some do it themselves for around 100$. http://www.lincolnvscadillac.com/showthread.php?t=69466 Oil Seeps into the plug/COP well, pools in depth down the threads of the plug, fouling it out. which in turn causes a dead short to the block, which in turn kills a COP in hours.
3. Moisture - OR STRAIGHT WATER in the COP wells, or under the cowl cover.
mostly causes a misfire on 3,4,7,8. if your #4,#8 plugs look like mine did:
chances are 90% you have a moisture problem.
moisture problems are usually caused by the foam seal which gets beat up overtime. Very noticible in the rain, or when driving during humid, or wet foggy days/nights. I usually use Red Silicone to seal it off. easier to obtain.
4. Failure to follow LS rule #1,#2. Replace one, Replace All. one kills the other.
5. Failure to follow LS rule #5. Improper gap WILL KILL COILS.
6. Coils were not done correctly before, to "Luxury" standards.
If your LS is having repeated single coil failures, without a legitimate reason (or coefficient) from above, the coil may be working too hard. too much resistance! In some cases a lean fuel condition (dirty injectors, vacuum leak or leaky EGR valve) may be the culprit. jerking, stuttering, or shaking at idle can also be symptoms of a vacuum leak.
users frequently ask, "how can i test an ignition coil?"
the answer is: test it with misfire data on a OBD scan tool. if it's missing, then assume all the plugs, and coils are bad. (save them in your trunk if it makes you feel better)
here's a chart from NGK regarding plug wear symptoms:
COP Ignition System Design Theory, Features, & Aftermarket Options.
1. Design Theory & Understanding
Coils work on the principle of Capacitance.
which just means the ability of something to store an electrical charge.
All coils are essentially transformers that consist of an iron core surrounded by primary and secondary windings. The primary windings are a much larger diameter wire than the secondary windings, but have fewer turns around the core. The ratio of turns between the primary and secondary windings determines the coil's output potential (the higher the ratio, the higher the maximum output voltage). Most coils have about 10 times as many secondary windings as primary windings. High performance coils have more.
With all types of coils, the primary and secondary windings are insulated from one another and do not touch. The resistance of the primary winding is typically very low, usually less than a couple of ohms and as low as 0.6 to 0.7 ohms on some individual coils. The resistance of the secondary windings, by comparison, is quite high.
here's a picture of a Motorcraft COP (PNDG529) that i spent three hours trying to tear into. (without ruining insides)
**DO NOT TRY THIS - CAPACITANCE SYSTEMS STORE ENERGY FOR EXTENDED PERIODS**
it's hard to see, but the copper showing is the secondary winding, and if you look closely you can see the iron core. (not a whole lot of core materials or technology here) half of these things size is the insulation!
So how does a coil actually fire a spark plug? When battery voltage from the LS's PCM/Ignition Circuit flows through the coil's primary windings, the iron core becomes a strong electromagnet. This forms lines of magnetic force that surround the core and envelop the secondary windings. When the ignition module (PCM) switches off the primary voltage to the coil, (open circuit) the magnetic field collapses. As the lines of magnetic force contract and rush back towards the core, they push along the electrons in the secondary windings and induce a high voltage surge in the coil. The voltage then passes from the coil to the spark plug. this whole process takes place with only two wires to each coil! 12v switched, and a PCM ground.
The PCM receives a basic timing signal from the crankshaft position sensor and sometimes a camshaft position sensor to determine engine speed, firing order and timing. It then looks at inputs from the throttle position sensor, airflow sensor, coolant sensor, MAP sensor and even the transmission to determine how much timing advance to give each plug.
2. Features - Aftermarket Vs. OEM Differences & Pro's & Cons
Despite Arguments, Personal Opinions, and Experiences, these are facts i've noticed in the design, and features of Aftermarket Vs. OEM Coils/Plugs.
A.) OEM/Stock Replacements
no matter what, no coil will last forever.
no matter what, no coil can withstand abuse from the issues listed above.
no matter what, no coil will make your car faster - End of story.
I've used all of these brands and here's what i've noticed.
>Motorcraft: +comes pre-greased +fits perfectly -3 month warranty -Expensive
>BWD, Duralast, Etc: +lifetime warranty+cheaper than Motorcraft -cheaply made, loose fitting, lack of design.
notice here the gap between the spring, and inside the boot (Motorcraft)
the spring will fall out.
notice here the sealing portion (top three rings) on the boot
all OEM brands i've used have lasted me (for what they could, due to VCG, and moisture issues) and have worked well for many users here. heck, our vehicles came stock with these parts!
ANY COIL THAT'S INSTALLED 100% CORRECTLY WITH NO VARIABLES WILL LAST!!!!!!! REGARDLESS OF BRAND. -unless its made in china, or not a reputable design
B.) Aftermarket (Performance) Coils
-MSD Ignition Coils
-all "Performance" COP units available
no matter what, these coils are not going to gain any additional horsepower,unless you additionally convert to a multiple spark (dual) ignition system and upgrade/tune injectors. **see Aftermarket Options below**
no matter what, these coils wont last forever, and if they aren't properly installed will not solve a thing.
>Accel COP's +cheaper than all OEM replacements +claimed MPG gains +warranty +easily available -requires harness modifications -requires brackets -requires removal of cowl cover
>MSD COP's +warranty +claimed MPG gains +warranty -requires harness mods/brackets -permanent removal of cowl cover
Currently, several LVC members, and myself are running the Accel Coils.
for anyone wondering: PN140032-8, Brackets are available from Hite, harness mods aren't hard, but there's a great risk of them breaking. So far, no problems.
notice the gap on the aftermarket boots (Accel)
that is a straight on shot, with no light shining through. spring is thicker, boots are more firm/physically have to pull spring out.
notice here the sealing ring up top. much thicker, more firm, better seal. makes a "pop" noise when you pull it out, as the spring is still holding onto the plug!
showing the reversed plug situation:
in my book, i would go with accels. pending they are installed correctly, they are a cheaper alternative to OEM, and will outperform OEM AS FAR AS SPECS GO.. NOT HORSEPOWER. example: turns ratio: 61:1 oem: 45:1.
that's my .02.
C.) Aftermarket Options - If you wanna spend $1500. :shifty:
THE ONLY WAY AN AFTERMARKET COIL WILL INCREASE HORSEPOWER!
- Disable Factory Ignition System. (stock OEM coils can still be used)
FACTORY ignition system permits coil functions. such as: dual spark during start up, single spark during high RPM, rev limiter, etc. so, no matter how HUGE your coil is, its only going to charge so much, and release so much energy.
i've put together a kit with part numbers for anyone that's interested. i would recommend aftermarket tuning, and injectors/fuel pump for a full effect with this mod. no idea what kind of actual gains you would receive.
1. MSD DIS-4 Ignition Module X2 PN62152 $579.95EA
2. MSD Ignition Adapters X4 PN89121 $72.95EA
3. Ford "COP" Wiring Harness (optional but recommended) PN88813 $99.95
Module A(1) will control cylinders 1,7,6,4
Module B(2) will control cylinders 3,2,5,8 <--- Firing order (A,B,A,B,A,B,A,B)
^ ^^ ^^^ ^^
total cost (with harness) on Summit.com
Prevention of Coil Failures!
1. clean it up! this includes everything from COP wells, to cowl, harness, seals, etc
2. Seal it up! if your going with OEM's, SEAL the cowl with Silicone!
if your going with accels or aftermarkets, check your hood seals, test them!
3. Lock it out! Moisture that is. Use LOTS of dielectric grease! grease the insides of boots (spring) bottom of boot (where it meets the plug) top of boot (where coil locks into boot) and the sealing rings!
4. do the job right the first time. remember the luxury rules!
if everything is done correctly, i see no reason why coils cant last 75,000+ miles.
hopefully this clears up ANY AND ALL coil confusion.
2,260 words... wow