Ford 2.3L Sparkplugs and Coil Packs

Alex from Lynchburg Virginia sent in these excellent suggestions:

Hey, my name's Alex and I have an 88 mustang with a 2.3, I work at Autozone so I picked up a set of 8.8mm plug wires and an MSD streetfire coil, you can definitely feel the difference on the top end. I also heard if you bring the plug gap from .044 to .050 youll gain a little bit of go. The next best thing to do is an MSD blaster 3 coil ($49.99) and the MSD 6al-2 ignition box($232.00), even if just for a daily driver application the multiple spark out put of the MSD box, and the tuning capabilities you receive are worth it.

Aftermarket Performance Coil Pack

The later year 2.3l engines had two spark plugs per cylinder and two coil packs.

Here's another performance coil pack modification but this time from Alan:

The MSD PN-8241, coil packs (currently listed for '95- '04 Fords ) for Mustangs etc, totaly applies to 90-04 Rangers. WOW, what a difference they have made, in just in starting my '92 Ranger!

Dual Plug Heads and Coil Packs

Ford engineers redesigned the 91 and up heads for dual plugs but not for performance but for emissions. The exhaust side spark plugs are used to create combustion. The intake side spark plugs are fired on the exhaust stroke to reduce emissions by burning unspent fuel. I did a simple test to verify:

  • Unplugged only the exhaust side spark plugs - the engine would not run
  • Unplugged only the intake side spark plugs - the engine ran perfectly.

I wonder if there would be a performance improvement to have both spark plugs firing on the combustion stroke? The firing order for the 2.3L is 1-3-4-2 so when cylinder 1 is firing, cylinder 4 is on the exhaust stroke and vice versa. The same applies to cylinders 3 and 2. So I did another test and swapped the ignition wires for the intake side coil pack: swapped cylinder 1 for 4 and vice versa. Did the same for cylinders 2 and 3. Swapping the ignition wires should cause both plugs to fire on the combustion stroke for each cylinder. The engine started up find and then I went for a test ride.

Swap Coil Pack Ignition Wires

I didn't notice any difference in performance at first. I have a steep long test hill that I drive to compare modifications and didn't notice any changes from before. It seems that it takes the ECU a couple of days to learn the change. I especially noticed the improvement when I was taking about 500 lbs of trash to the dump. I barely noticed that I was hauling anything! It is a worthwhile change as the engine runs better.

This is a simple free modification that you can easily do and if it doesn't work or make an improvement, you can easily change it back to original. You may get an error code that is "rich at part throttle" - the Check Engine light occasionally comes on when I first accelerate then turns off. I'm interested in seeing if there is a gas mileage improvement too.

Change your Sparkplugs

The latest generation of 2.3L have long life sparkplugs, we're talking 50,000 miles. It is easy to forget to change them routinely. If your 2.3L idles rough, it could be that your sparkplugs are worn. The simple solution may be just to change the sparkplugs. This can also result in a 1 to 2 mpg increase in gas mileage and a performance improvement. Several people have emailed me that they have had excellent results with the platinum plugs.

Platinum Spark Plugs

I have mild pinging (detonation) in 4th or 5th gear at low rpm under load. This could be because the stock spark plugs (Champion RS14YC) are running hot with all the mods. I've swapped in the next step colder plugs (RS12YC) to see if this will help decrease the pinging. It is a simple modification that costs $20 for a set of 8. The toughest part is getting the plugs out on the intake side. A long extension will make cylinders 1,2 and 3 easy. Cylinder 4 needs a universal joint at the sparkplug socket then its easy.

Reading Spark Plugs

There's a lot of information on the Net about reading spark plugs and gathering information from them. Some sites go quite deep into what they can tell. One site which sells a book on how to read spark plugs, states that the author can tell the ignition timing - static and dynamic from the spark plug. His interpretation of the sparkplug goes directly against manufacturer's sites.

There's many sites out there so I'm not going to recap it here but here's what you can tell from reading a spark plug:

  • The spark plug is worn or damaged
  • The cylinder is leaking oil

Unless you are racing then there's not too much information on a well used spark plug that will help you except to tell you it's time to change them. And if you are racing then you will probably use many other methods to determine the performance of your engine other than spark plugs.

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Copyright February 2011 Eugene Blanchard