Ceelomane17

Hi i just bought my dream car the rx8 but it has problems. Its hard to start like its flooded followed that procedure then when started it has rough idle then smoothens out and you can drive it nice and fine but after say 20 seconds to 30 it begins to sputter and come to a stop and then die like an alternator. Hooked a obd2 port up and its running like 5 sensors and monitors but no codes. Heres what came up:

Rx8 obd2 diagnostics:

Green solid:
(MIS)- misfire monitor
(FUE)-fuel system monitor
(CCM)-comprehensive component monitor

Red flashing:
(CAT)-catalyst monitor
(EVA)- EVAP system monitor
(AIR) - secondary air system monitor
(OS2) - oxygen sensor monitor
(HTR) - oxygen sensor heated monitor

YELLOW LED LIGHT SYSTEM STAUTS

Emission related engine DTC's:
No powertrain DTC's or freeze frame data is presently stored in the vehicles computer


It also has a check engine light thats solid and sometimes flashes

TomX8

Flashing CEL is always a misfire.
Solid CEL can be anything, such as a dirty ESS.

I got both, and it turns out that my cat is probably really badly clogged. Check the insides of the cat, it might be a stuffed kitty causing your Problems. Otherwise, get compression tested. If you open the airlock, you can pulseread the compression. Even if you have low compression, try to seafoam the engine regardless, there has been an admin on here who regained 2 full bars of pressure.

Ceelomane17

Ah ok well how do i check the cat and if the cat is clogged how do i unclog it or do i just have to buy a new one? And sorta same thing with the compression test, can i do it my self or will i have to take it in somehwere? Im pretty new to the rotary and really just newer cars in general the only other car ive had was a 1994 honda accord lx not even vtech lol but yeah ao i know like how to keep the rotary maintained pretty well but im not good with diagnosing this kind of stuff but im trying to learn lol

UnknownJinX

Welcome.

Your car is, well, not very well received. Early 4-port/192 with 4AT RX-8 is the most problematic out of the bunch.

Please read the new owner sticky thread, which will greatly assist you.

The very first thing you need to do is checking the compression of the engine. You need a special compression tester for rotaries. Go to a Mazda dealership or rotary shop near you to see if your compression checks out. If your compression checks out fine, then you can proceed with the troubleshooting; if not, you be the judge if it's worth the effort and money to get a new engine(it's the best to part it out; no one with any RX-8 knowledge wants the 4-port 4AT). Really, this should be done before you bought the car.

Did you disconnect your battery recently? I have an OBD2 scanner like yours. If your battery has been disconnected, then the red lights will take a couple of drive cycles for the computer to check the car.

If your car floods regularly and your compression is okay, chances are the ignition system is busted. Change your coils and spark plugs if not already done. If you have the cash, BHR coils are highly recommended over the crappy OEM coils.

The best way to check the cat is jacking your car up and taking it off to physically look at it. You could also take it out for a rip, and look at the cat immediately afterward. If it's glowing, it's shot. There is no way to "unclog" it; you'd have to get a new one or hammer the element out for a temporary way until you can get a new one.

Also, check for possible vacuum leaks and clean your MAF and throttle body.

And please use punctuations in the future, thanks.

TomX8

Pretty much what Jinx says. Check the CAT physically, if it's clogged, either hammer the insides out (watch out for the o2 sensor, take it out first!) or just get a new one for 200 bucks.

You could check the compression yourself, as I said by releasing the airlock and cranking the engine. It will jump around and give you a reading for each face, but that's just a backyard Approach. Film the needle boucing, write down the numbers and identify the compression per face. No Need to get a 100 buck compression test. All you Need to know is whether it failed, is borderline, or good.

Dont worry about the Emission Monitoring System, These checks are not interesting to you. What is interesting to you is Trouble codes and other OBD2 sensor data do Diagnose what is wrong with your car.

How does the car start?

Love_Hounds

What good cat. costs 200 bucks?

Also that "compression test" tells you nothing.

TomX8

One that is made out of steel with the catalytic converter made out of ceramic covered with platinum, ECE approved? Why would I spend a thousand bucks on a new converter when one of 200 can do the same Job. Gut the old one to drive with, use the new one to pass Emission testing.

Besides, that 'compression test' is fine if you film it and measure every third compression pulse to a rotor face. The actual Rotary Compression Tester does exactly the same Thing except it's digital.

Love_Hounds

Because the new one will melt, quickly, resulting in the same problem. But you're right, you can spend a ton of time under your car switching midpipes if you want.

You need to know the RPM at which the readings are taken to determine the compression.

Ceelomane17

I appreciate your alls responces. I got the car for 1500 and when it did run. it ran really well not a single miss its was like it was just bought off the lot, for a mile, then started to sputter like not hard but a couple kicks then slowed down and stopped and all the power killed. Im not sure how to do the compression test that way im not good at directions like that and ive never heard of it done. And im not necessarily like trying to be a bitch about it but im starting to turn my head on rotaries simply because its either a hit or miss if you have a car or not. Does anyone know of any cheaper engine swaps? I say cheap because after i sell the rotary and trans ill have 1000 and help from some people but i need to be able yo go to work and save up for extras but my job its 25 miles away so no bus or anything. If anyone could help me getting it running for like a month thats all ill need.

Ceelomane17

And also i was ok with the automatic because my girlfriend dors not want to lesrn she barely wants to drive but incase i need her to she can without ******* the clutch and tranny up. And i also liked the paddle shifters and slap shift. I did resesrch i just didnt know they were so bad. I do not at all want to get rid of the car or i do want to keep it i just need a more simpler engine soley because i have a lot of responsibilities that require i dont spend every last dime on keeping the rotary alive

UnknownJinX

I have heard that ceramic cats can at least withstand street driving. The catted version of the BHR mid-pipe utilizes a ceramic cat and is only 100$ more than the uncatted version, but they do warn you not to use it for any hard driving. Using them just for emission tests should be fine.

Removing the cat in the stock pipe will result in a louder car, keep that in mind.

And yes, a proper compression test is worth the money. A backyard compression result is mostly useless.

A word of wisdom I have seen on this forum is that RX-8 is not a car you wanna cheap out on.

It sounds like a compression problem, but hard to say until you have the numbers. Pay the money for a rotary-specific compression test if you want to troubleshoot because otherwise, none of the fixes will help.

An engine swap is not a cheap option. You may as well sell the car, and look for a 6AT 6-port from later years, or better yet, learn how to drive a stick and get a 6MT 6-port version. RX-8 is best served with MT, with its AT version being very heavily criticized(mainly due to the lower red line).

If you are really desperate and your engine does have low compression, you could possibly try the Zoom-Zoom cleaner or even the ATF method. Keep in mind that these methods are gambles; sometimes they work, sometimes they don't.

Lastly, check your automatic transmission. All of them need good fluid to run well.

Rotaries are not a hit or miss; they require more attention. Before I bought mine, I looked through a lot of the resources here. Definitely not a good first car, I'd say. And every car out there has issues. You think Honda Accords are reliable? Well, turns out, the one I owned has a very well known issue for burning oil due to a faulty cylinder-deactivation mechanism. Mine didn't have that issue, thankfully. The 1999 Corolla I had also is well known for badly designed oil rings that will easily sludge up and burn oil. Remember to research the car you want to buy and what to watch out for prior to purchase; this goes for ANY car.

Ceelomane17

Ok well its not exactly the point that im trying to "cheap out" the rx8 its that i got 2500 and paid 1500 for it figuring i can get it running enough to work. Ik how to keep them very well maintained and i also never said one thing about the accord being reliable *hence why i got rid of it*. i plan on putting well over 3k into the car but over time not all at one time to get it running if i did that id get a charger put the 3k in and smack you at the red light just because. But thats not the point nor who i am. I get that they need attention and i love cars more than anything literally saved my life 4 times, but to just drop every last penny i own is just absurd all i need to do is get it running and i can work for the rest but,my job is also 25 miles away like i said. I appreciate everything ive been told but have you not stopped to think that all i want is the body and maybe i just need some help for now till i get the money to swap it. I didnt think so cuz your not in my head i get your a rotary fan but try not to shove it down peoples throats like that i never expected to go cheap on it i have a good job but premixing at every pump, checking your oil every day, Having nightmares about apex seals and not being avle to go to work i mean theres so many factors. Noe as the performance they are great but you have to take care of them down to T which yes you should do for every car but like, i do have a life outside of that. My bad on the rant but i hate it when people tell me who i am and what i should do based on their beliefs like sell the car over a swap? Or that im going in this trying to cheap out? And also the reason which you never told me how much a rebuild would be for but ive been told by mazda a rebuild or new engine would be 9k all in all.

Ceelomane17

And also i know how to drive standard i never also once said that i didnt know i said my girlfriend doesnt and doesnt want to learn. I said i was ok with it and liked the paddle shifters.

UnknownJinX

I wasn't saying you are cheaping out. Regardless, sorry if I sound a bit harsh.

As for the engine rebuild price, $9k is highway robbery. If you are just trying to put in another 4-port, you can talk to a rotary shop around you to get a better idea. I think it should be at least $3k, although I think other people have a better idea.

Selling the car over a swap was just a suggestion that makes more financial sense, unless you want an LS swap or something like that. I have heard some places can do it for $10k or so.

Regardless, please get the compression number before you jump in. Like I said, if you have a failing compression, there is very little you can do, other than trying the Zoom-Zoom cleaner and possibly the ATF method.

Lspankin

okay ! I lost interest once we started arguing, I bought a high flow catalyst.converter for my 2006 rx8 made by magnaflow for about 180.00$ bucks. on amazon. it works great, no check engine light came on or anything. And I live in New York where it is the law to have catalyst converters on your car. We have emissions inspections every year here. I agree. take out the cat and beat the guts out of it with a hammer and long chisel. at least you will know once your done that it's not a clogged cat that's causing the problem. clean or just replace the spark plugs , also cheap on amazon about 30 - 40 $ Driving the car hard under a load in first or second gear to about 6500 rpms will help clean the engine out and yes this should be done under a load not in neutral or parked. I usually punch mine entering the highway to clean her out. As for compression testing I haven't done one on a rotary but I agree with doing it with a standard compression tester. Just get an average on the compression. take out the spark plugs ( the top trailing ones) screw in the compression tester and crank it a few times. this will give you an idea as to whether there is enough compression or not, above 80-90 psi should run but 125 is really good. On another note, these cars should never be automatic. That's like buying a lamborgini with an automatic, you will never enjoy or get all of the performance out of the car. Many rx8's with auto have cat problems, because no one drives them hard enough to keep the cat clear. rotarys burn oil so the cat clogs easily. you have to run them hard to keep the cat clear. if your gonna keep an auto rx8 you should do 80 mph for two minutes every week to keep the cat clear. I love my baby. rotarys are simple and easy to work on, they just need a little more maintenance than a piston engine does but so worth it.

UnknownJinX

A couple of things:

1. Magnaflow cat won't last long in our exhaust if you drive hard. Our exhaust is too hot for them. If you want a cat that lasts, a used OEM is the cheapest option.

2. Don't chisel out a perfectly good factory cat. These things are worth a bit. Either keep it so you can put it back on when you sell the car, or sell it to someone who needs it for emissions.

3. Lambos and most supercars nowadays are automatic, mostly dual clutch transmissions. Why? They shift lightning fast. The moment you move your hand to the shifter in a manual, a DCT has already finished shifting, and these supercars have one goal: go fast. If a DCT is the fastest, so be it. Even a good automatic nowadays is faster than a stick. RX-8 is just in an age where automatics still suck. Not anymore.

New Yorker

UnknownJinX

Kinda hard to argue for the environment when you drive a rotary.

Personally, I don't think that far. I just don't want my car to be perpetually in recirculation mode(especially in rain) or be faced with that nice fume.

Loki

iTrader: (1)

Also this thread is from 2017. I think everyone in this thread has moved on by now.
Oil is a minor-to-none contributor to cat clogging. Modern oils have little in the way heavy metals for this exact reason. Incomplete combustion and rich condition is what gets them.

Lspankin

this is an old post , and I do care for the environment. and I know that lambos are automatic with shift paddles , and I know that they shift faster. my point is manual shifting is more fun. and you have more control of the engines rpms. with paddle shifters all you can do is delay shifting or keep the car in lower gears longer. I would still prefer to manual shift than to paddle shift thank you. and I agree not to chisel a perfectly good cat as they are expensive due to the platinum grid inside. maybe take the cat out and run the car with a straight pipe just to diagnose if it really is the cat that is clogged. I would never run my car without a cat. the smell alone from the exhaust is unbearable. and I am an environmentalist. please don't misunderstand what I'm saying.

Lspankin

and burning oil does contribute to clogging cats. burning oil means more carbon. carbon build up is bad for cats.

Lspankin

burning oil means more carbon. of course this will clog the cat more. low rpms due automatic transmission shifts will never allow the engine to rev high enough to reach hot temputures combined with oil consumption , and not enough air flow all add up to clogged cats.

Loki

iTrader: (1)

The temperature of a (happy) cat is always around 850-900C. It self cleans just fine, as long as the exhaust coming into it is not so full of fuel that it's accumulating faster than it can catalyze it out, and more importantly faster than the cat can cool itself down. If you think about what a cat does, it's literally burning fuel, which produces heat. Too much fuel = things get melty. So again little-to-nothing to do with oil. Don't confuse cat deposits with engine deposits.

I see no evidence anywhere that automatic cats fail more than manual ones, I don't know if anyone has kept track of those things. And forums aren't a good indication, people don't post problem threads when they don't have problems.

UnknownJinX

There is no reason to try and say things just to please anyone here. You are giving me that vibe here.

I like a stick shift better as well. Just stating some facts here about DCT and automatics.

You know what builds up even more carbon? Gasoline.

If you are losing sleep over it, mod your car to run on E85, hydrogen or add a methanol/water injection kit.

And technically, cats like lower revs because hot exhaust is much rougher on catalytic converters.

Also, watch the Engineering Explained video on carbon buildup. Higher temperature isn't necessarily better. It need to be very high, or very low so the deposits don't form in the first place.

I did hear that one problem with automatic transmission is that, since the torque converter is very close to the rear rotor, the heat it produces can add more thermal stress to the rear rotor components.

Lspankin

i'm not saying anything to please anyone. and yes you can state all the facts you want. I know what a cat does and how it works thank you. and yes more fuel or raw fuel due to a misfire will literally melt the guts of a cat. I've seen and experienced this first hand thank you ( 25 plus year working on cars and the last 15 years on diesel trucks). I haven't seen any forums on automatics clogging cats , I agree. I only spoke with one woman who told me her automatic rx8 kept clogging cats. Maybe due to running rich due to a vacuum leak? I don't know I never worked on the car. im just trying to help a fellow dorito that's all.