(First off - Kudos - I have been a member of this board for some time now. The amount of information on this Forum is amazing. I do a lot of searching, and and find just about everything that I have ever wanted to know about my RX8 on here. Thanks to everyone that posts, it makes a huge difference)

OK - I have been fighting this misfire for the past 10 days reading stuff on the forums here, trying stuff, and today had smoke come into the cabin of the car and coming out of the hood, so I decided I better create my own Thread to track this issue case someone else has this problem.

Issue started with a hesitation, and CIL. Pulled code and it was P0302. Found a thread talking about a Fuel pump issue, and how you can not make a sweeping curve when going xMPH under 1/4 tank of fuel. Being that I was just under a 1/4 of fuel when this originally happened, pointed blame at this. Filled up with gas, good to go for a couple days. I borrowed my to my Brother-In-Law (20 Years Old) for 3 weeks. He told me that the issue came back while he was driving it.

Got the RX8 back about 10 days ago. Check engine light was on with P0302 code. Removed code. Drove car for 2 days no issues. Then the light came back on, lost about 50% power, sound was throaty, and idle would become very low (stall on occasion) . This would stay this way for about 1-2 miles, then it would run fine again. CIL was on again P0302 issue. Came back out here, found the 20 brake peddle stomp trick. Did that, worked for a day or so, then P0302 came back with same symptoms, 50% power, throaty sound, low idle. I then found another tread about the same 20 brake peddle stomp but adding the steering wheel turn gig.. Did that left then right. This cleared the code and the problem for about 70 miles. When the issue returned this time (2 days ago) I decided I was going to replace the plugs as there was a burning odor when at low speeds (I assume at highway speed the smell was still there just being pushed away from the airflow).

Last night I replaced the plugs, which were in need of replacing BTW. The Trailing (top) rear rotor plug was solid black, with a fair amount of carbon buildup on it. Leading (bottom) rear plug was pretty worn, and needing replacement. The Front ones, looked OK, with the exception of some buildup on them, but were a brownish tint. Cleared all codes and brought it for a test drive. Same symptoms. The P0302 code came back, but had P0171 along with it this time.. Progress or step back not sure... So I decided to bring the car home.

Being the guy that I am, I could not sleep as this is really starting to get to me. So I went outside, pulled the Crank Position Sensor off (Thanks to RX8Club forums again) there was some metel shavings on the sensor.. Cleaned this off well. Did the ohms test came back at 1155 so this was in spec, put it back on the car, drove it around (8.5 miles) and it ran PERFECT.

Got up this morning.. Jumped int he RX8 Pulled out of the driveway and about 2 min later... Power loss, sound, CIL, low idle...

I continued my drive into work. The CIL going on and off, power issue coming and going at random. Got about 8 miles into my 11 mile trip, and was sitting at a stoplight, CIL ON, Misfiring happening, Throaty sound happening, Holding RPM's at about 2K to prevent from stalling. Burning smell getting really bad, and I start to see smoke entering the cabin at the shifter, and the arm rest area. Smoke was getting thick, so I rolled down the windows. At this point I am getting nervous. Mind is thinking Smoke=Fire Fire=Get Out! <this is about exactly what I looked like at the stoplight. Well I stuck it out, pulled away from the stop light, CIL turned off, Car pulled away from the light PERFECT.. Rest of the ride (about 3 miles) went flawless. Car ran like new.

Here I sit at work, wishing the damn thing would have caught on fire... OK that is a little extreme.. But I am getting very upset with this thing. Tonight I was thinking about moving the back two coils & wires up to the front and moving the front 2 coils & wires to the back to see if the problem follows the coils or the rotor.

Anyone else have any thoughts or direction on where to go here? Wife said to bring it to the dealer, but I am afraid of what that would cost. They quoted me $1,000 for plugs and coils.

Couple questions:
Compression Tests: Does it matter if I use the Leading or Trailing plug for the tester?
Do I need a Special Compression Tester, or would a traditional compression tester work? Threads on the plugs look normal, but want to make sure as this is my first Rotary motor.

Coils: Is there a way to test these besides moving them to the other rotor? If so, I must have missed the thread in my searches with the specs on how to test.

I would like to fix this, or at least diagnose this issue myself. I have pretty much all the tools I would need, just missing some of the knowledge, which I hope to get from here. If I don't have the tools, I will go get it.

Any direction would be much appreciated.

Edit to add details about car:

RX8 Details:
2004 RX8 43,xxx Miles
Manual Tranny
BONE STOCK

 

1st: Where are you, $1,000 for plugs and coils is probably a record. Considering you have already shown mechanical aptitude, buy the plugs ($80 for all 4) and coils ($140 for all 4) from a forum vendor, and take the 20 minutes and replace them yourself. Don't get voluntarily raped.

2nd: The smells, smoke, power loss, etc... sounds all cat related to me. Have you looked under the 8 and seen if it was glowing during any of this? I'm guessing not or you would have mentioned it. I like detailed writeups like this Even when parked, you can look for signs of melting around the cat and sensors.

3rd: Test, a complete and accurate compression test requires a total of 6 readings, 3 from the front rotor, 3 from the rear rotor, along with an RPM that the engine cranked at. This does mean that you need a compression tester that is able to record the compression for each rotor face individually as it spins past at 200+RPM. The analog ones from auto parts stores don't cut it. There are a few out there that will do it, but it's costly, several times more than the cost of a dealer doing the test, so it's not really cost effective. I don't know which plug is the right one to use, or if it even matters.

4th: You can test the coils with a multimeter, and check the Omhs on each of the varying contact points. However, coils go bad well before they actually fail offcial Mazda spec.




Overall, you probably do have a severely failing coil (or more than 1), and the excess gas fouled the plugs on the rear rotor, then clogged the cat. Cat can't evacuate the exhaust, you get localized heat buildup, stuff starts to melt and burn, you have massive power loss, etc...

Your cat probably keeps having chunks clog up then melt away.

 

You can confirm cat failure through several methods. Glowing red is one, though a dealer might not take it. Pulling the cat off and seeing a jacked up interior is another, but the dealer might say you damaged it pulling it off (uncommon, but it's happened). If YOU are convinced it's the cat though, then let the dealer diagnose it if you are within the 80,000 mandatory federal warranty. Warranty will cover it.

If you are outside of that, then either hunt on here for a used cat, or buy a midpipe. With a midpipe, you will probably get a permanent CEL unless you are lucky (not everyone does), or have something to mask it (like an AccessPORT).


Severe cat failure leads to additional problems though, such as
- continuing to destroy your plugs, new or old
- roasting your O2 sensor and making it fail, completely or inconsistently
- catching your car on fire

 

I'd say start out by check plug wires, check the resistance see if they are to specs. I don't use OEM so i'm not sure what the specs are, you probably can find them here on the forums. My buddy was getting misfires and it was due to a spark plug wire with higher resistance/faulty, he couldn't rev past 6-7k and would get the P302 code. Then check your coils if you have stock and its more than 30k old and has white spots underneath, you probably need to replace them. I recommend LS2 coil upgrade, BHR sells them as a kit. The lean code, i've had that one before when i upgraded my headers, midpipe, intake anything that changes normal air flow will give you this code, pull out the "Room fuse" on the driver side kick panel (15mins) and it should reset fuel trims. Our car sets 3 fuel trims anything out of the ordinary will give you this code, assuming you modified ur car. If not try cleaning your MAF, check for vaccum leaks, 3 little hoses that connect to the intake follow them.. You could have a bad cat as well with the smell, burnt plastic i had that before got a midpipe done .

 

RIWWP - Thanks for the reply(s). I will check the Cat today on the way home. I looked at the cat a little when I was under the car for the plugs, but really didn't focus on it too much. Everything looks normal at first glance. But to answer your questions in order you asked:

1.) I am in Minneapolis. It was Morries Mazda in Minnetonka off 394. The Exact cost was $954 I rounded up the $46 as I figured they would find a way to do the same. <- Crooks Being my car is the 2004 version (I just added this to my original post BTW.. Sorry I missed this MAJOR detail). The coils come in a pack, NAPA wanted like $450, Dealer wanted $550 I have not checked anywhere online, cause I am hoping to by stuff local so I can work on it without waiting for shipping.

2.) I will put the car in the situation again, then take a peek at the Cat. When I looked at the cat when doing the plugs I didn't see any signs of melting. I had my OBDII Code Reader hooked up when it did that today.. The Cat Temp was about 1500 Degrees. Not sure what it should be , and to be honest I have searched on that spec either. I will do some research and see what I come up with no the "Normal" temp of a CAT.

3.) Called the dealer $210 for a CAT inspection and Compression test. Being this is the only car that I think I will own with a Rotary motor, I would have to agree with you that going to the dealer to do the compression test and CAT inspection would be cost effective. The compression tester that I have is the analog style, but has a bunch of adapters. So I would not be able to capture the reading you are talking about. I did some searching for Rotary Engine Compression testers and found a few but they are about $250. and have multiple leads to replace plugs... Yeah Dealer bound on this one

4.) Do you know the Omhs reading specs for the Coils? Done some searching and I am coming up empty handed. Maybe I am searching with the wrong keywords . Help to obtain some solid numbers would be helpful.

2nd Post:
I am within the 80,000 miles. At about 43,000 on a 2004, so I am really leaning to the dealer after I eliminate the coils from the possible cause.

Added Details about the issue:

I have noticed that on warm starts the issue isn't are prone to happen. Cold starts, it is about 95% of the time. The only time on a cold start it didn't act up was after doing the peddle stomp, steering wheel turn deal.

Junirol -
Thanks for the reply. I will Omh out the wires when I do the coils to see if there are any issues there as well. I will try to pull that "Room Fuse" as well tonight. Being that I am driving a Bone Stock car I suspect putting OEM stuff back on should get me back to stock running performance.

Thanks for the replies guys... Wish I could get out of work here and get this car running right.

 

Sounds low. We normally run at 1,800 to 2,100 degrees I think. Could be a sign of thermometer damage.

$210 is still high, but doable. Most dealers are in the $80 to $140 range for compression testing.
Actually, the Mazda specs are entirely "if 0 ohms" or "if infinity". There are no specific numbers. It's one of the pain points we have. They start causing problems before we have a chance at a precise test to determine if they are failing or not. Typically, replacing them every 30,000 miles fixes them about the time they start to fail. Assuming everything else is good with your 8 (which isn't the case here), you can detect coil failure through observation of how the car is reaction, idling, reving, etc... But when other issues are present, it gets messy.

Handy. Warranties help a bunch there

That sounds like the O2 sensor is certainly giving you issues as well. When my O2 sensor got fried from my cat failure, I was chasing my tail for 8 months before I finally replaced it on a hunch and it fixed the issues. Most of my O2 sensor problems were after cold starts.

$280 from Mazmart (just so you know in case the dealer tries raping you there)

 

OK - Leaving work today the 8 was acting up right away. I let it sit and Idle as I spoke with a co-worker of mine. While talking with him the 8 died. He left shortly after that. I got it to restart (very difficult, very simular to flooded situation) got it to idle again for me and poked my head under the car. Found a glowing cat! Called the dealer and they agreed that the cat was faulty, and would replace the cat free of charge on Monday.

Now comes the trivial question. Do I go get a set of coils tomorrow and swap these before I bring it in, so they cann't charge me the $300 in labor I was quoted to replace these, or do I hope they don't blame the coils and just replace the CAT. What are the thoughts on this.

Does the clogged CAT cause the rotor to misfire, or does the rotor misfiring cause the CAT to clog?

 

I'm going to jump in real quick.

Is there anyway you could live without driving the car a day or two?
I just don't recommend driving the car in it's present state. Only bad things can happen..AND....things can get worse!

So, if you can avoid driving it, at least buy the coils here http://www.finishlineperformance.com...cat=338&page=2 or http://www.mazmart.com/ItemDetail.aspx?id=609 and do them yourself first! Maybe even have them overnighted is still going to save you money over the dealer. You could put those coils in in about 30 minutes probably.

Get plugs as well. I was having trouble finding plugs right now at either of the two linked above, buy BHR has some.......scroll down the page. http://blackhaloracing.com/products-...gine/ignition/

Also, attached is how to check the coils(just use "C"), but has been stated...........they can go bad even when they pass this.

Now............the CAT is under warranty, so you could just hold firm and say, I just want my CAT replace as it's federally mandated and that's it.
Then I would immediately take the car home take and replace the coils and plugs.
Hopefully you would have already ordered them and they would be on the way from somewhere.
When you are through, get cleaned up and take the wife out for a nice dinner with some of the money you just saved!

 

I agree with Mazurfer. If you can avoid driving it until you can get the cat replaced, do so. That severe of a clogged cat is already going to be costing you in other repairs. No need to make the issue even worse. And if you burn down your car from driving it like that, please avoid the forums for the rest of your life

Just tell them to replace the cat. They can not refuse the cat warranty because you aren't letting them replace the coils. If they try to pull some BS on you, take the car back and let it sit until you get the new coils in, then bring it back. But tell them that new coils are on the way, it should mollify them.

Generally, the order of failure is:
1: Coil fails, generating weak spark and excess unburned fuel, misfires possible
2: Excess fuel fouls both plugs in that housing, further weakening the spark, causing even more unburnt fuel, misfires likely
3: The coil for the other plug begins to degrade faster, as the spark isn't allowing smooth release of the power, excess unburnt fuel volume is snowballing in size, misfires probable
4: The excess unburnt fuel is all getting shoveled into your exhaust, and into your cat, along with the oil that isn't getting burned completely as well
5: Cat begins to break down, chunk up and blow out if you are lucky, clog up if you are not
6: Cat clogging limits exhaust flow, and further power loss begins (other than the power loss from the misfiring and weak spark), this power loss begins from the top of the power band and works it's way downwards as the exhaust flow becomes more and more restrictive.
7: You tend to push the pedal farther and farther down for the same speed, even if not noticably, dumping more fuel in, or lower gear, to make the same power, accelerating cat failure even further
8: As power loss becomes severe, the efforts to continue driving at normal speed is generating ALOT of heat, and that heat can't go anywhere effectively, and accelerates localized heat buildup
9: The localized heat buildup begins damaging things, what depends on which elements of your cat failed probably. Either or both O2 sensors are likely (lots of carbon, unburnt fuel, exhaust, and heat), heat shielding and shrouding begins to glow and melt, oil temps climb and oil breaks down faster, engine working to evacuate the exhaust gases is straining more and the stress on the side and apex seals can begin to damage them. Worst case, the heat catches the underside of your car on fire, and with the fuel lines not that far away, the fire is fast and hot.

(disclaimer: Most of this is is known, several points of exactly what is happening is conjecture and theory. I might be proven wrong about some of this at some point.)

1 through 4 can take a while to happen, 5k-10k miles possibly. 5 happens faster, and it's an accelerating failure at that point.

When my cat failed critically, it went from ~16-19mpg and slight power issues to ~11-15mpg and noticable power issues in about a month, from there it got to 9mpg and bad power issues in about a week. From there it went to "unable to maintain highway speed" in about 36 hours, maybe 4 hours of driving total.


From the symptoms you describe, if you drive it until the dealer replaces the cat, you are on the edge of risking fire, and well into where it's continuing to cause further damage.

Please avoid doing this

 

dont drive the car if you dont have to before getting the coils. buy the coils as per above from finish line or MazMart. or try onlinemazdaparts.com. change them yourself.

they are going to blame the coils if they have any clue in their heads- because they are the cause of the cat failure. but that doesnt matter they have to replace the cat per the federally mandated warranty. you wont have to pay the "cat inspection" fee.

what you are experiencing is classic leading coil failure

 

I don't think we can make it much clearer as to what our opinion is.
There are a few on the forum that might like to argue what points RIWWP, Zoom44, and myself have made, so keep driving at your own risk of further damage and expense if that's what you decide.

But.............We(or at least I) would be interested in what you decide to do and when you get it all fixed up okay? Make sure you report back.

Thanks and Good Luck,

Dave