Im going to go ahead and ask this well aware of the fact i may get flamed. Either way, i dont know if Ford STILL does this or if it was just on my mom's expedition or what. We went to change the plugs and wires once on it, and were quite baffled in that i dont think we saw wires, and for sure couldnt see plugs, and there were all those little yellow round things, 8 of them. I think they were yellow anyway. I assume those are the coil packs.

My question is this...why oh why do you need EIGHT packs instead of ONE coil? It almost seems WAAYYY too over engineered. Im sure there is some advantage....thats where you guys come in. Whats the purpose? Just redundancy, or to scare owners from working on it, what?? Im sure they dont want owners poking around in it as evidenced by the many plastic covers and shields. Either way, the Expedition runs like a champ with ORIGINAL plugs, wires, or whatever the hell it has-- all with 140,000 miles.



Thanks

 

Those "yellow" things were probably the injectors. The coils are larger round things right next to them that extend deep into the head where the actual plug resides. Should be black with a silver top for the most part.....

Can't explain why they use them, but there is no distributer to worry about. No loss of energy from the coil having to send current through a long wire. No wires to worry about replacing. The computer is able to detect a misfire on the exact cylinder and give you a code telling you what cylinder to look at. The earlier 4.6 engines use two coil packs and actual plug wires. Seems you hear about them having to change the wires all the time.

We don't have push rods either and use two cam shafts....

 

Coils put out a max of @ 20,000 V. if you run that through a wire you can have resistance that will cause less voltage to reach the plug. Also, if your single coil goes bad you are dead in the water. Now if one your coils goes bad you have a performance problem but can still motor to where youcan get it fixed( sometimes many, many miles from where you first moticed the problem.) The other reason most manufactures have gone to multi coils is a better control of the ign. system. Still, if you folow the theads here you can see that a blown coil is a major cause of performance problems. Are the single coils more suspect to failure than the regular coil? Hard to say. I would rather loose one cylinder than 4 or all eight.

 

One of the reasons for 8 individual coils is that you don't need plug wires. If you had one coil then you would need a distributor to put the spark to the cylinder you want. This all adds up to losses in the spark energy. You would have to fire one coil 8x as fast as individual coils. With coil on plug, there is power to each coil, and the computer grounds it to fire it. It is much more effient and cheaper to maintain.
Ignition systems have come along way. Except on Dodges.

 

No distributor, and no plug wires.....thats the answer.

Thats good to know.....however, i've never had a coil go bad, and i can still limp along to the next town too. Here is where MY thinking may differ.

I have ONE coil to go bad, EIGHT wires that could go bad, a distributor, and a rotor.

You have 8 packs and some wires.

I dont know how, but my truck can and has detected misfires and ID's the cylinder that misfired. Mine was due to a wire i had snagged on something when i changed plugs. The thing that i still don't understand is what is good about having one pack per cylinder. So its more efficient with spark delivery...so what...so MY coil just has to be alot 'juicier' to get to 8 cyls thru wires. In the end, they both spark, they both ignite a fuel mixture and drive a piston. Thing is, I can replace my whole ignition system for the price of ONE or TWO coil packs. The only advantage i can see is the ability of being able to limp home should the coil pack fail. So, i go shell out 15 whole bucks and get a spare coil and keep it in my toolbox. More importantly, i can pull over, open the hood, determine the coil failed from the MIL and replace it with standard tools in under 10 mins.

The reason i ask all this is that i almost bought a Ford, it happened it was way more than i wanted to spend (dealer's fault). My mom has one, and i tried to repair things on it and im almost insulted by the plastic covers, hidden bolts, expensive parts, and special tool requirements that (to me) have been implemented in an effort to keep me, the "dumb" owner from repairing anything. Obviously, if you own one, you work on it and get used to it and its not a problem, but at first sight, it was/is quite daunting. So far, my mom's and my fiance's (02 FX4 SCREW) have had no problems, hopefully they will continue that way. I must say i am impressed with my mom's expedition. 5.4L engine, the ONLY thing that has ever been serviced in 140,000 miles is the oil.

 

Also, if you get a distributor wet, you don't drive away. You can run on 7 cylinders.

 

I suppose.

 

Don't let these guys (or gals) intimitate you. You raised some very good questions that Ford Motor Company itself would be needed to step up and justify.
Do I like the fact that my ignition system can crap out after 20-40k miles? Nope! Am I happy mine shows no noticable signs of deteration after 70K? Yep!
They all have different things and different agendas based on.....? what? Better torque, longivity, lower cost....????
Yep, but more importantly (at least to the designer and/or engineer) will their $100K plus a year job be safe and secured if he/she recommends this change and it saves the company $$?
Welcome to my world, at least, the way I see it!

 

Some pictures of coil on plugs can be found here...

http://www.svtlightnings.com/svt/how...lugs/plugs.htm

Some links...

http://members.aol.com/carleyware/library/copign.htm

COP used by Indy cars...

http://www.sdsefi.com/techcomb.htm

 

wanna run it? I'll meet you halfway!

 

Well, it will run on 7 or even down to 5 cylinders, and it doesn't run well, but it will get you out of a bad place and back to safety, instead of getting out and trying to dry a distributor out. I have run my truck home on 5, 6, or 7 cylinders plenty of times. Not by choice, but it got me out of the coyote and bear territory and back to civilization. The bad part of this design is, there's more parts, so there's more to go wrong, but the good part is, it's very unlikely that it will all go bad at one time. The c.o.p. design may be superior to the coil packs, also, because if a coil pack goes bad, you've lost 4 cylinders, but if a c.o.p. goes bad, you only lose one. There are upsides and downsides to both designs, but the c.o.p. is more modern and advanced technology, and with the way that modern engines rely on technology to run, the c.o.p. fits really well in their design.

 

Negative, ghostwriter.

At any rate, don't LIKE the expensive parts ford has on their engine, but i DO like the technology. When i got my truck back in 1998, an oil change was quite an undertaking. Now that im mechanically gifted however, i often wonder why my Dodge engine has many similar parts as my 1970 Oldsmobile engine, only in a MUCH smaller form. Only difference is a computer and fuel injection. It has pushrods, like mentioned. I was wondering why they didnt step into the modern age myself. However, that probly wasnt at the top of their list. At that time, the most important part was designing a truck that was very very different in hopes their company wouldnt go down the tubes.

When did the ford truck engines do away with pushrods and switch to DOHC?

 

To me, the Ford COP system makes a lot of sense, and not having to deal with constantly deteriorating plug wires is a good thing. Plug wires can't stand the heat well and deteriorate pretty quickly...they build up more resistance over time. And 9 times out of ten I end up spilling oil on them when I add, and that ain't good for the wires either.

What I fault Ford for is making the freakin' plugs so difficult to change! The steep windshield rake angle means half the engine is under the cowl, and the OHC heads mean that the plugs are buried 3" down in the hole. And we don't even want to get into the "not enough threads" issue that has caused plugs to blow like Old Faithful.

That being said, the plugs are still changeable for the average Joe who doesn't mind bloody knuckles, a certain level of frustration, and having the neighbors tell him to "Stop that damn yelling and cursing!"

We deal with it!

 

97 was the first year for the 5.4, but Ford has had the 4.6 out for some time before that.

Nothing wrong with the old tried and true engine design that's been around since the dawn of time (pushrods, OHV, distributer, single coil).....

Add some new technology to the mix (OHC, Coil on Plug, Multi point fuel injection, MAF, IAC......) you get even more efficient and more power, but also more expense and more possible failures....

My old 1971 LTD with a 400 in it had maybe two wires that went to it! Might have had one to the carb for the choke too...... but that was it! All adjustments were made to the carb. Want it to run rich, turn a screw. Lean it out by turning it the other way..... Idle adjustment was the same thing. You could put in those .99 spark plugs. Oh, you did have to adjust the points all the time too...... Got 12 mpg and had some power, but less then my 330 ci engine in my truck......

Yeah, it's a PITA when one of the thousands of sensors go out, but at least the computer will tell you which one it is, so that helps..... Just part of the times now. It is the 21st Century, and we were supposed to be living on Mars by now (according to the movies of 30 some odd years ago....), so I guess getting our internal combustion engines to run on mostly electronics is just the start to getting there!

 

I've got a little over 50k miles on my '02 right now, and I've had 2 coils go bad on me already. It's obvious when it starts failing, but to replace it is another story. First they're not cheap. And second, they are a PITA to change. I took a look at my father's '04 Silverado the other day, and looking at his engine bay (5.3L), it makes me wonder why i didn't buy a Chevy. All of the coils are easily accessible, and even the headlight's were designed so that all you do is pull a pin and out comes the headlight assembly to change a bulb. Maybe someone with an '04 F-150 can chime in if the redesign went any better, otherwise for maintenance, our engine bay sucks.