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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
 
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#95 ·
i just bought the motorcraft cc spark plugs and some msd 8.5 wires i put them in today gapped at .065 and my car ran like absolute garbage, smelled like eggs and ran like ish. I put the normal plugs back in left the wires on and the car runs normal, but backfires and spits alot when you get off the gas, it also stalled once (it has never done any of this prier to me putting in new plugs and wires) ?????? ANY HELP
 
#97 ·
Re-check your wire connections, I've always been under the impression that MSD wires dont work with the stock coil.

Also check to make sure your firing order is right.
 
#102 ·
I'd put the stock wires back on, just to make sure.

BTW, .065 is a bit on the high side gap wise.
Most of us that have installed the coppers on NA engines have run a .060 gap.
(And...I still stand by Taylor wires all the way.)

Oh, make sure you check the wires going to the coil.
Not the plug wires, but little wires coming from harness connector itself.
The wires are pretty tight right there, and have been known to fray or break.
 
#103 ·
sorry cant make it to your apt tommorow gotta work, im just gonna throw the stock wires back on hope it straightens out and i am just gonna go and get the msd coil pack or see if i can return these msd wires.

OH YEAH i tried to get the taylor thundervolt wires but they were on back order til the 21st so i said F it.
 
#107 ·
Ok i pulled my msd wires off and put them back on fiercly, warmed the car up and took it out for a drive it seems to be running back to normal, idle is at 900-850 steady everytime (once it did drop low but picked itself back up accordingly). For the member that said the msd wires wont work with the stock coil, you are partially right they make two kinds of the wires one set for the stock coil and one for the performance coil. (i do have the set for the stock coil, i have read you dont need the high performance coil anyways). So i believe that i just gapped my plugs way to big and didnt have my wires shoved all the way on. I will post agian if something goes wrong or i have other questions thanks alot everyone who helped. [hihi]
 
#108 ·
For the member that said the msd wires wont work with the stock coil, you are partially right they make two kinds of the wires one set for the stock coil and one for the performance coil. [hihi]
That was me, I've never seen a set of regular MSD wires... I've always seen the "lock on" type.


Glad to see it up and running again.
 
#114 ·
Its called indexing, you face the tip of the spark plugs toward your intake manifold, supposed to help with combustion, its some old school hot rodder trick.
 
#115 ·
Actually you are suppose to face the spark plug opening toward the exhaust valves... that way when they ignite the "explosion" is already traveling towards to exhaust valves as they are opening, thus giving you better scaveging and a higher exhaust flow rate.
 
#116 ·
Hi There, After waiting far too long I recently did some spring cleaning and changed my fuel filter, plugs (Motorcraft Coppers gapped to .060) I haven't noticed any real difference. It feels a little sluggish and even had a bit of pinging launching up a steep incline last weekend (the first I've ever noticed). My plats had over 100.000km's on them before I changed them out, but I haven't changed the plug wires though. (I have 2 year old Steeda's and a new set of Taylors Thundervolts waiting in the wings) I just want to know if I should be adjusting the gap smaller before I change my wires or if the wires might be the reason for the sluggish mid RPM feeling I am experiencing? I thought I would notice more than just a smoother idle.
 
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