Focus Fanatics Forum banner

Ask your spark plug, wires and coil questions here

214K views 469 replies 172 participants last post by  amc49 
#1 ·
I've decided to make an "ignition" thread.

and post up answer's to the more commonly asked questions.

Do I need to upgrade my coil?

Simply put.... No
Stock coils will provide enough spark to support over 700whp. The average 4 tower coil will put out between 36-40k volts most aftermarket coils put out only 42k MAX. You will not see any gains what so ever by swapping out a working stock coil for an aftermarket one.

Do I need to go with those really expensive plugs?

Again.... No

Unless you have a HEAVILY Modded (MORE THAN BOLT ONS) engine there is no need to use any other plug than STOCK. You CAN re-gap the stock plugs to .060 (in most cases) and you will get a smoother idle and the overall running of the car will be improved... but just slightly. When you open up the gap it take MORE voltage to jump the gap and make spark.. therefore wider the gap the hotter the spark.

Now if you are running Nitrous of Forced Induction then yes you can benefit from changing plugs. I highly recommend the MotorCraft AZFS22C f4 sparkplugs. They are copper cored (which is one of the BEST conductors of electricity.. better than Iridium) and will provide a wider,stronger spark. They also work VERY well with NA engines,and at $8 a set you cant go wrong.

Should I change plug wires?

Yes

Changing your plugs wires is problely the most effective ignition upgrade you can do on a Focus. Any descent low resistance wire is MILES beyond the stock wires... I can not say how much I despise stock wires for there inability to carry good voltage. Remember the bigger the wire the better... smaller wires will heat up internally and heat greatly reduces their ability to conduct electricity.


Well thats your basic ignition questions covered... feel free to ask any questions that you have.

John
 
See less See more
#438 ·
replaced coil pack with oem replaced wires with borg warner 8mm ones checkd the pigtail for coil and wires look in decent shape. green and blue wire has a sliver of wire showing. and under boost the car misfires like a mofo
 
#440 ·
Hi I'm new to this forum and I kinda wish I would had became a member before I bought my plugs and wires. I just got my hands on a 02 Focus SVT and decided to give it a tune-up. I got some LTR5IX-11 4344 NGK Iridium IX plugs reasonably priced on eBay and I also bought some JBA PowerCables (W06809). I've read mixed reviews on Iridium plugs here, can anyone tell me if putting the gap to .57-.6 is the way to go with those plugs or should I return them and go with MotorCraft's. The wires are low resistance.
 
#442 ·
changing spark plug wires on my focus...help

Hey there. I recently been to the mechanics and paid them almost a grand on some repairs. I just been told that my wires need replacing and the cost will be $172.72! I do NOT want to spend any more money than I have to and I think changing the wires out will not be difficult but I would like some feedback from someone that really knows. My car is a 2002 ford focus zx5 2 liter in line4. Ive got O'reilys for only 33 bucks on the wires which is sweet. Can anyone please help me out here, I would be ever so greatfull!
 
#443 ·
Hey there. I recently been to the mechanics and paid them almost a grand on some repairs. I just been told that my wires need replacing and the cost will be $172.72! I do NOT want to spend any more money than I have to and I think changing the wires out will not be difficult but I would like some feedback from someone that really knows. My car is a 2002 ford focus zx5 2 liter in line4. Ive got O'reilys for only 33 bucks on the wires which is sweet. Can anyone please help me out here, I would be ever so greatfull!
You can get Motorcraft (OEM) wires for that price on Rockauto.com, which I highly recommend for good prices. There are always a lot of options, though, so you need to know what you're looking for.

Motorcraft WR5973 - $25.79 (SOHC)
Motorcraft WR5974 - $29.99 (DOHC)
 
#444 ·
Anyone know where to get a decent deal on a stock Motorcraft coil pack?
 
#446 ·
Will the coppers work no problem for a stock focus? I have msd super conductors currently with stock double platinums. I never checked the gap last time (silly me) but the plugs and wires now have about 53k miles on them and it has a bit of a rough idle now.

My MSD plug wires look to be fine but I was looking at grabbing the coppers and gapping them to .60 as everyone is saying but is that for the SVT only?

Thanks
 
#448 ·
From what I've read in this thread and others on the same topic you should be fine at .06 regardless of motor zetec , duratec , or svt as long as your Na (naturally asperated) if your fi (forced induction (supercharger /turbo)) you have to start closing the gap .04 and lower depending on boost level . also not sure if it was a typo but gap is measured in imperial so .6 would be over 1/2 an inch , hope this helps
-cheeze
 
#447 ·
Ok I know this post is ancient but I hope it's still active ... I've read this whole thread and countless others so it's not for lack of effort , here it goes ... So if the motocraft sp-463's are supposed diritec spark plugs that are reccomended (in this thread) for the Zetec motor will the a103's also work(also duritec)? Also the sp-463's are platnum not copper ... And I'm looking for copper plugs and can't seem to find them for some reason... Thanks in advance

-cheeze
 
#449 ·
SP-463's are for the Zetec engines, as they're all known here in the US - std. or SVT.

A103's, 104's or AR versions are for the Duratec engines, again as we know them here.

Not always in stock everywhere, platinums and other fancier plugs are more common & profitable to sell.

Try to avoid confusion from Zetec & Duratec being used differently in other countries - for example our SVT is equivalent to an ST170 in Europe, and the engine (same as ours) is called a Duratec ST in that model.
 
#450 ·
Whats the difference between the SP-463s and SP-524?

I recently purchased plugs from Advanced, and when looking up what plugs were available (I specifically requested Motorcraft brand) they gave me the 524's.

Did they give me the wrong plug? I'm a little confused here, as I see 2-3 different plug numbers that are mentioned.
 
#453 ·
Whats the difference between the SP-463s and SP-524?

I recently purchased plugs from Advanced, and when looking up what plugs were available (I specifically requested Motorcraft brand) they gave me the 524's.

Did they give me the wrong plug? I'm a little confused here, as I see 2-3 different plug numbers that are mentioned.
Sorry it took so long to get back to you no they didn't and a heads up for everyone SP-524 is the new stock number
 
#457 ·
I have an 07 Focus SE 2.0 Duratec. I use AR103 spark plugs gapped at 0.55". Rides nice, but I don't want to burn out my ignition or any wires, so I have a question:

NAPA says my car doesn't have plug wires - only coil over plug boots. If people are upgrading plug wires to at least 8mm to handle wider gaps on plugs, and I don't have plug wires, do I need to upgrade my coil over boots or can the stock ones handle AR103s at 0.55"?

Thanks for the advice!
 
#460 · (Edited)
After reading through this thread I decided I should go check my spark plugs because my neighbor had gapped them when we were trying to figure out why my engine was misfiring (ended up being a broken wire in the coil pack) and I'm pretty sure he didn't gap them correctly. Sure enough, I check them today and they were only at ~.050 which would be on the low end for my (mostly) stock SVT according to what others are doing. I gapped them up to .060 and it definitely felt better even with the stock replacement plugs and the stock wires. I'm thinking next time I change the plugs I'll be going with the copper cores to see what kind of a difference that makes, and then possibly switching to some aftermarket wires since I'm sure these ones are towards the end of their lives.

EDIT: I didn't mean to say the guy didn't gap them correctly, he just didn't bother to ask where I wanted them and just kinda threw them in the car.
 
#462 ·
Um .06 is a little high for ours also. I drop mine down to .05 and it feels a lot better, it depends on the power you're making how you want to gap it. Anyway stock gap is 1.5mm which is .051 in SAE you're gaping to high.....imho....
Stock gap on a 2004 SVT is 1.23mm to 1.37mm (.048" to .054").
Taken directly from the emissions decal under the hood.
1.5mm would be .059", check your math.
 
#466 ·
Stock Motorcraft Spark Plug Wires No Good?

Any descent low resistance wire is MILES beyond the stock wires... I can not say how much I despise stock wires for there inability to carry good voltage.
John,
I've read several posts that say stock wires (and I'm thinking that means Motorcraft) are fine.

You seem to disagree, so I'm confused. [???:)][scratch]

Are you sticking by your original statement? Is any clarification needed?

Anybody else want to weigh in?
 
#467 ·
Not going to debate a post from '07, we lost John a while ago now and special cases and parts can apply.

What you'll normally find is all of the same resistance value, special low resistance or even solid wire types are a separate category. When you go to solid wire you'd need to find resistor plugs if you want to eliminate RF interference, haven't actually seen those for cars myself in a long time.
 
#468 ·
Do you really need all 4 screws to screw down the coil?

Because one of them was stripped by whoever installed the coil last time, and another screw dropped and I can;t find it even with a magnetic handle.

And what is the size of that screw? So I can get another one at the Hone Depot instead of spending $10 each from the dealer.

I used a NOS coil that was made in the USA (even Motorcraft/OEM comes from China now), and I have NGK Laser Platinum spark plugs and NGK wires.

If I couldn't find the NOS coil, I would've used the NGK coil (made in Mexico)
 
This is an older thread, you may not receive a response, and could be reviving an old thread. Please consider creating a new thread.
Top