And the data for this is where, exactly?

If you use the calculator I provided above, you'll notice that at even a 10% bigger gap, the "strain" on the OE coils is negligible.

The part of the coil that fails is the ignitor. The coil itself will practically live forever.
What kills the ignitor is voltage drop and heat.

You do the reading on that. You'll discover the plug gap has nothing to do with it.

 

the data is all over the place. I just gave some myself about my talon. It started misfiring above 14psi and to fix it, all I did was regap the plugs to .025 again. they wore to .031 after several pulls at 21psi.

the calculator does not take into account intake temp, humidity, and current state of coil(s) so, it is 'bench racing' calculator.

Tell me something about what I dont know....heat kills anything in time....voltage does not mean much of anything and the gap has everything to do with how much heat is generated when producing the spark by the coil. When you introduce heat, you start changing things chemically. You could have a 9 volt battery to your tongue and it will just tingle/hurt slightly...up the amps and it will kill you....hense the batter that starts your car. 12v at .0001 amps will tingle...12v at 600amps will knock you into next week.

Nothing to read as I work with this stuff every day I work. I make wire and anneal it (anneal means to soften through heat for those that do not know so that the metal is maliable again and not hardened)

closing the gap slighly will take a HUGE load off the coils and not from a voltage standpoint but an amperage standpoint.

Reduced heat/voltage, given ignition system is working correctly yields longer laster system including the coils/ignitors as well.

 

Just for you MM. They are all over the place.
http://www.powerarc.com/sparkplug.htm
even ngk says the same basic thing and they make the stock plugs.

go with the smallest gap that keeps the coils/wires from wearing out...overheating and the gap, as I said before and NGK says it as well, the size of the gap has a direct relationship on the amount of current needed to fire the plug. The over all current and not just the voltage as voltage is just one aspect of current. amperes is another.

As sparkplugs wear, the gap widens. Common sense tells you that if you start with a smaller gap, it will put less wear on the other components, given they are in good shape compared to a larger gap, given the other components are in the same basic shape meaning....the larger gap will cause more wear on the components. I can find more sites if you want me to.

the mod works. rule of thumb, more compression/power the car makes, you need a better ignition system or smaller gap. Plain and simple.

 

if you are going to 'quote' me, it is not wise to pick part of a sentence out. let's not go through this again please. I do not do it to you and do not do it to me.

 

I wonder when and how Mazda and NGK went wrong when the engineering team specified the coils, wires, and spark plugs to be used on the Renesis engine.

 

^^ you can ask the same question about the engine and other specific RX-8 issues. It almost makes you wonder ....

 

Every rotary ever made has had "Ignition" or Spark 'issues'....every one of them.

 

Since the rotary was made, it ran hotter, in general, than piston engines...especially back in the late 60s to mid 80s. I am sure that many of you remember the 'reactor' exhaust it used to have instead of a converter around the time gas went up in the 70s.

Point is, the gap will become larger, faster due to the very nature of the engine and design. Mazda did not go wrong with anything. They just did the best they could based on price in order to keep selling the motor that is, in many ways, ahead of its time. No ignition system is perfect for any car.

there are, basically, 3 ways to deal with the issue

change the plugs often based on driving preference as autocrossing, racing, or lots of spirited driving will wear the plugs faster than just cruising.

set the gaps slightly lower to offset the progression of the gaps widening so you do not have to change them as often given same driving habits

get better coils that will fire when the gap exceeds the capacity of the oem coils and causes issues

the above is assuming that the ignition system is fairly new and in good operation as in new/amost new plugs, wires, and coils.

There is more than one way to deal with the ignition system 'potential' problems and the 3 above can be done based on what the owner feels comfortable with. They all work to a degree. good maintainence habits are essential for this engine to ensure proper operation as every will agree.

 

You make a replacement for it so, very good question indeed.

 

Replaced all four last week. Very easy to do once the air box is removed.
The white spots on the bottom of the coil were also there. These coils made it for 40k mi. Not sure why the coils went, all four had the white spots, but the problem coincidentally occured with a bad battery. The dealer wanted to do a throttle body cleaning before any diagnosis was done. A neon bulb spark tester was used to determine the problem was in the coils before taking too much apart.

 

glad you tested instead of just buying.
What about your plugs? What kind of shape were they in? It's recommended to change plugs/coils at the same time.

 

I want to preface this by saying that I am technically competent enough to change a battery or tire. That's about it.

My 8 was exhibiting the signs of cat failure, namely, glowing orange cat.

I had the cat replaced earlier this week, and the 8 ran fine for a day, then started sputtering and stalling.

I just had new plugs and wires replace in March, the reason I didn't have the dealer do the coils is because I'm unemployed and couldn't afford to have everything replaced at the same time (stupid, I know).

After sifting through the forum to determine what was wrong with my 8, I thought it might be the coils.

Once I removed the air filter housing, I saw the coils and thought that I might be able to do this myself.

Bought the coils and replaced them. Fairly straightforward, just slightly difficult to access them.

Before replacing the coils, the 8 wouldn't start.

When I pulled the coils out, they all had the telltale white spots on the bottom.

After replacing the coils, reattaching the battery cable, I put the key in the ignition and crossed my fingers.

She fired up immediately.

I let her warm up, and took her for a bit of a spirited ride.

The 8 feels like her old self again.

Thanks to dozer for the excellent DIY with pictures. Without it, I would have been hosed by a dealership for about $280-$340 for the coils alone (which I bought for about $120), not including the labor.

Thank you, thank you, thank you.

If I can do this, truly anyone can.

 

I recently had engine trouble with my 2005 RX8 (37,600 miles). It was diagnosed as bad coils and fouled spark plugs. Performance Mazda in Houston, TX quoted me $1,105 to repair. The quote included 2.5 hours labor charge. The mark up on the parts was 200%. After reading your posts I did the job in 45 minutes and right at $200. There is no way this dealer can justify 2.5 hours labor. They are a complete rip off. If you live in the Houston Metro area stay away from these con artists. Thanks so much for your instructive posts.

 

Just finished replacing coils. Took about an hour from start to finish. Hardest part was disconnecting old coil from plug. I knew I had to pinch the clip problem was I didn't know where to pinch. For any newbies that are going to try this you need to push down on top at the very end where the wires come out. Then the coil comes right out.

Another tip that made it so much easier is tweezers. I used a pair of tweezers to hold the bolt because I couldn't get my fat fingers down far enough through all the wires to get the bolt started. It worked great.

As for the air filter assembly. I removed the air filter, then I just loosened the 2 clamps on either side of the round flexible tubing, slid that out and just pushed over to the side and had enough room to change the coils.

I was hoping to notice an improvement and was pleasantly surprised that it made a very noticable improvement. It idles smoother, revs smoother, and the lack of power at lower revs was hugely improved.

Wouldn't have been able to do this without this great site and all the great info from the more experienced RX-8 owners who have contributed. Thanks guys!

 

Hey guys, just changed my coils and wanted to say thanks to the original poster for the pics. I have 57,000 miles on the car, bought it used last year with 44,500 on it. I don't know if the coils were still the original or not. I was getting the hot start issue, lack of power, rough idle you name it. I ran tests with torque and my obd2 adapter and saw all the misfires, so I hurried up and got the coils.

Swap took about an hour. Everything was super easy. Upon initial start up, it ran smooth but the revs jumped around at idle until the ecu settled down. My dsc light was flashing and traction control turned off for some reason. It may have been due to the obd2 adapter still being plugged in. I drove it, stopped and started and all was back to normal after 10 minutes.

Low end power is back, idle is smoother, no more hot start issues. Ran the tests with torque and misfires are about gone, registered 3 on "cylinder 1". I am changing the plugs and wires this weekend to complete the job, and that should take care of everything.

I can't believe the difference in the car, so much power is restored. I got the coils shipped free from advance auto with a 20% coupon for a total of 85 bucks. Can't beat that!

 

When I pulled the coils out, they all had the telltale white spots on the bottom.


this does not mean that your coils are bad

 

Thanks for the DIY. I followed the directions (and spark plug replacement) to replace my coils. Look at these crap coils and corroded plugs. Wife's 2005 RX-8, 39K miles.


By sleestax at 2012-07-20

 

Thanks for the DIY. With this and the one for the spark plugs, I saved $600+!

 

Replaced, plugs, coils and wires and the DIY information was invaluable and definitely saved substantial dollars over dealer pricing. Only issue I overlooked was the tip on removing the connectors for the coils, squeezing the back of the connector rather than the tip. After a frustrating few minutes and a quick reread of the DIY (and posts) made for an easy re and re.

 

anks to all the posts in the DIY section!!!
I bought the coils, plugs and wires from Mazmart and changed them all out this weekend. Since I am a "ahem" mature woman, 5-1 and 130lbs... my little hand and skinny arm... I only removed a little plastic "box" off the side of the air intake and my little fingers made quick work of it all.
I ran her up on the ramps and didn't even turn the tire, much less remove it... I can crawl nearly up in the wheel well... the plugs weren't bad and my son helped me replace the wires one at a time... a breeze!!! I saved $400 on parts alone... can't imagine what the dealer charges!
I'm in Houston and if anyone needs any pointers, it's seriously as easy to do as it sounds.
Thanks again for all the generous folks that don't mind sharing their knowledge!!

 

Since the air intake removal is the first thing we have to do to change coils, I'd appreciate it in the DIY if we had some shots of the stock air bellows, and getting that out. This original DIY showing an after-market air intake that's not in the way in the first place isn't much help for us totally stockers.

 

go on the AEM website and they have PDF instructions how to remove the stock intake for the AEM CAI. ez peezy.

 

Or you could just look at it and realize that there's two hose clamps (one on each end of the accordion tube) that need to be loosened, then the tube comes off. Really not that difficult and nothing that needs to be in a DIY. SMH.

 

Yeah, OK Fuzt...of course I don't have a problem with two clamps...but my 05 Shinka has about 50k on it now....and those hoses on the air bellows won't budge....and you know how brittle (or maybe you don't?) those black plastic nipples the hoses go on get after years of 100mph on a regular basis ....

.....so you guys are telling me nobody had any trouble at all getting those hoses off without breakage??

 

Oh...by the way EricB.....what's the "AEM" website you'retalking about?