Running too rich..
 

needing help with this guys i have no idea why i would be running too rich every tells me this aside from already knowing this..

i have replaced this on the 8

intake,
cat
and deleted resonator
and the have the racing beat catback..

i use plus fuel instead of premium cause obviously its a bit more expensive and burns faster it seems when i was using it!

so any help would help thanks in advance

With a high flow cat, cat back, and K&N panel filter I would log ~11.0:1 AFR when loads exceeded 80%.

If you want to lean this out, buy an accessport or hymee tuning package and make the necessary adjustments.

Lower octanes would burn faster than higher octanes...they have a lower combustion temp. Try switching back to a higher octane and see if that helps. Gas cost should not be a concern to an RX-8 owner...

well a newborn baby 16 hrs a week job and about 20,000 worth of debt will make a man pinch some pennies even if it is just a 10 cent differnce..

even when i had it at premium it still was running too rich..

i know for fact i need to replace my iginiton coils which i can do myself its just that 150 bucks is murder to my pockets for now!

would that be a factor??

At $.10 a gallon on a full fill up you would be saving less than $1.50 per fill up, over the course of a year if you fill up once a week you would save less than $100. The savings is about the same as a bottle of coke or a cup of coffee, there are better ways to save...

What makes you say it is running rich? Have you had the AFR's read? And if so, what were the readings? I am just asking this hoping you are not assuming it is rich due to the build up on the tail pipes...

Ignition coils wouldnt cause it to run rich, would affect the ignition of the fuel in the housing, but not how much fuel is being thrown into it.

Just because you changed those parts doesn't not change the amount of fuel going into the engine, the air/fuel ratio, or the timing. Only the accessport can alter your situation. You can switch exhaust, midpipe, intake, etc till the cows come home, you'll still be programmed through the ECU to burn the fuel you're instructed to burn.

u can smell it.
a couple mechanics mentioned it as well..
were do i go to get these readings?? its smells like pure gasoline when i drive around, unbearably at that!

You sure its not a fuel leak somewhere? Have you noticed any decreased fuel efficiency? And finally, not trying to insult with questions like this, but you do know that the Renesis engine by design runs a bit rich to meet emmisions testing, right?

Any Mazda dealer or decent mechanic shop should be able to get you an AFR reading. I believe it can be read through the OBD2 system, but may be mistaken on that.

see i didnt have an understanding of how it was actually working..

ok good.. thanks!

yeah its not i checked when i got work done on my exhaust

and no fuel efficiency decrease..

i did not know that the renesis was designed like that..

and okay i will check into an afr reading! thanks again for all the information

There is no design issue whatsoever. The engine will only run rich as I mentioned above at high load points. For idle and cruise the engine targets and operates at 14.7:1 and sometimes even a little leaner - none of which is considered rich.

All the cars with a stock ECU run relatively rich. This isnt a huge problem though, you can tune it for slightly better performance and fuel mileage, but as mentioned this requires an expensive accessport, interceptor x, or some other ECU replacement or reflasher. Don't worry about it, and if you dont want it to smell put the cat back in.

Am I not right in my understanding that in order to meet US emmisions standards the motor was designed to be injected with excess fuel so that it could ignite and burn off additional hydrocarbons in an expansion chamber before the cat converter?

Maybe I just mis-spoke in saying that it is designed to run rich when I should have said something more accurate along those lines? I am still learning the motor myself...

repeat after me

octane tells you nothing about how fast a given fuel burns. period.


back to point.


if you were running excessively rich the car would notice and light a CEL. If you are actually smelling unburnt fuel while driving you have a fuel leak.

Now you could have a cat that's going bad- they smell awful... and no it wont necessarily light a cel when the cat goes.

You are actually on the right track. Look at it like this - ideal burn is 14.7:1.

The vast majority of the factory engine calibration in daily driving will get you right around there - idle and light cruise conditions. In moderate load, you will be at low 14s to high 13s. High load situations are where it operates very rich - like 11.0:1.

Mazda programmed in this high load rich condition to save the life of the cat due to stricter EPA catalytic converter requirements. This is where excess fuel is being sent into the engine. At all other points of engine load, Mazda actually does a pretty good job of sending in the correct amount and definitely not an excess.

I've been told first hand that some have reprogramming their Renesis to idle at 16:1 and cruise at 15.5:1 instead of 14.7:1. This should save some gas, not sure how much as I've not tried it.

Ahhh, that does shed some more light on it.

Is there any downside to running the engine leaned out like that? Would it run any hotter or increase the chances of detonation?

now i dont know if its actual burnt fuel or not but my CEL is on. i hope i dont have a damn fuel leak.. where would the best place to check for that be at??? any local mechanics?? i sure as hell anit going to the damn stealership!
















*

Take it to pep boys or auto zone, they can read your OBD2 for the CEL code and tell you what it is for.

To lean it out, add nitromethane.....


:FIREdevil



:eek:

I have my doubts that at specifically idle that this would cause any issues. At the same time, I have nothing to substantiate this so take it with a grain of salt.

But for the amount of gas being saved to me it doesn't seem worth the effort. Maybe you'd gain 1-1.5 mpgs...the people I spoke with regarding it raved about the improved gas mileage. As a multiple rotary owner, I've learned to accept that "good gas mileage" and "rotary" rarely are in the same sentence in a positive light.

correct me if im wrong cuz im not the most knowledgeable, but did you replace your cat with something other than a stock cat? because anyone on here knows that running catless gives off a horrible smell that could be classified under what your saying. im running catless and people ask me all the time if im leaking fuel or running too rich. i tell em its just how my wankel works :yelrotflm

i didnt delete or remove the cat i replaced it with a high flow racing cat

there is a resonator right after the cat, something like another filter if you will

but it could damn well possible be that..

becuase it wasnt until after i did these mods that i started to notice the smell in more potency!

Is this smell coming from the front of the car or directly from the exhaust? I had a similar issue with my 87 Turbo II and it ended up being the fuel pulsation damper. When it started to go bad I started noticing a really strong gas smell, but it was coming from the engine bay. In a nutshell gas was leaking on my down pipe therefore enhancing the odor. It's a shot in the dark, but it's worth looking into.

wow,

now we get somewhere.

you replaced your cat with what? what hi flow cat? at how many miles? how many miles on the new cat before the cel light came on?

why didnt you think it might be a good idea to find out what the cel meant?

btw, just for fun. maybe a little bit of info about your car?

mileage, year, mods, auto or manual?

why did you change the stuff out?

beers :beer:

okay.. 2004/ 104,000(roughly) / mods are listed above but i'll repeat / and 6 speed

custom cold air intake/ racing beat cat back exhaust

unknown type of high flow racing catalytic convertor

and than deleted resonator with straight pipe to the racing beat exhaust system

why did i do this??? well why does anyone mod a vehicle.. it sounds fucking amazing now and for a bit more performance.

so continuing

now this is what happened guys and girls my CEL has been on since back in feb or jan.. my throw out bearing gave out on me at the same time that one of my rotors faild due to my ingnition coils i found out.. i checked the light at autozone first because it is free..

the codes where all about the AFR and the ignition coil which i new

i went to the stealership to confirm and i got robbed for 90 bucks to find out i already knew what i was talking about

okay so my CEL stays on for months turns off at random for maybe a couple weeks or days than CEL again!

the CEL was not affected by the new mods it was affected by what happend in jan. btw driving with one rotor active , smells horrible and is a tear jerker! :wallbash:

if any other question i'd be happy to answer buddy!

Well, if anyone was worried about the CEL, everyone here should know why it would stay on. Also, one ROTOR? Stop driving the car and take the bus. If a any mechanic cannot find the problem then................. maybe new engine lol.

Even if your car was healthy in the first place and you had replaced the stock parts with aftermarket parts, your CEL could still come on right then and there or could have eventually came on later. I added the racing beat midpipe and my CEL stays on but before that all I ever needed were new coils and plugs but even then my CEL never came on. Some of the smells could be from your aftermarket catalytic converter. I have about 90,000+ miles on now and still running strong with no issues. Also, keep in mind that you need to go to different mazda dealerships, some are better than others at finding problems.

you bought the car used with these after market exhaust parts on it? or you put these parts on? Im having trouble understanding since you say you dont know the brand of the cat.

oh where do you live- yes its important for us to know the area you live in- and how was this "one rotor" issue resolved?

Similar Issue
 

Bought my 2005 1.3 Shinka about a year and a half ago. Love this ride. (didn't think anything would top the Spyder) Any ways, last winter I got a CEL. Put the reader on it and it threw a 420. Asked around and the most popular opinion was a bad cat. Found that really hard to accept at 53K miles. In the coming months I replaced: plugs, wires and ignition coils. Significantly more power like didn't have to downshift to 5th when going up the same hills I went up before! It took about two weeks before the light came back again. Car ran just fine with no issues. Then at just over 59K I started noticing a bad odor from the exhaust. Smelled a car that was running rich with a burned fuel smell. There's a little gray smoke but you have to look hard to see it. I finally broke down at 61K and bought a replacement cat unit from Amazon. It's more like an exhaust extension but it's called a cat. Took it to my local mechanic as I just couldn't get under it enough to change it. At the same time I had ordered the lower O2 sensor. He got them replaced (charged me $50 to do it), nice. He told me the old cat and pipe weighed a lot and agreed the cat was plugged. Definitely more power than I've ever had with this car. That said, the odor is still there with a CEL. He said he tried a couple of adjustments for intake but to no avail. Really hate to take it to the dealer. The issue reminds me of an EGR valve issue but looking at this mess I'm lost. That's my story. I went through the new user forum and don't see any thing that jumps out. Any ideas that I can try before doing the dealer option????

A perfectly operating factory catalytic weighs a frigging tonne.
They are heavy bastards period.
Most aftermarket cat IMO are ok but most can't get rid of the smell and may not pass a smog test or have a very long life.
If you use a cat -delete pipe .. WOW the car really stinks or smells awesome if you love unburnt hydrocarbons like I do!

Catalytic failure is common on these cars, very common.

So the cel is likley P420 Catalytic efficiency below threshold, you should get it checked to be sure.
The smell is to be expected.

Don't want to worry you but driving around with a failed cat can lead to premature engine failure.
Look around the forum. Enjoy

Edit:
OH I would love to know what the "adjustments to the intake" were by the mechanic

So your saying that your car even told you that the cat was clogged (p0420), and you ignored it because the mileage, then drove it anyways, and now your finding out that the cat was indeed clogged and it's causing you pain and misery?

This is what happens when you don't listen to needy bitches (the rx8).

You replaced ignition components, sure. But driving around with a fouled cat can cause bad stuff to happen in your engine, and your new ignition may be toast now (because it had to work harder).

Yes, it could be the new pipe you have that's causing the rich smell. But you could have unburnt fuel getting thrown into your pipes because, with the afore mentioned, you ignition is dickered.

Get those checked.

Second, this "exhaust extension" could also be dickered because it can't handle the high exhaust temps of the renesis, destroying or clogging it.

Get that checked.

Report back :)

Thanks for getting back
 

I originally posted to those needy bitches posting the question about that cat asking is 55K about right for a cat. All I got back was cat. You need to understand something, dickering with cars for over 30 years, 55K doesn't seem right for a cat change. The beginners forum showed that the RX does go through cats but doesn't say the mileage range to expect this. Had someone said something other than cat and answered the question, then we're good. When I read about the cats going bad I'm thinking maybe 90-100K. I've had cars that went 200K without a cat change. I've replaced these before as well as done other work.
That said, the miles driven on the car since is minimal but the issue remains about the strong exhaust smell that started before the cat replacement and didn't go away. I was able to find out that the mechanic who was playing with this (backwoods guy) was trying to adjust airflow rates at the intake? That's a new one on me but without a good manual I have to go with what I'm told. As previously describes, if this was a late 70's or 80's car it reminds me of an EGR valve not opening re-burning exhaust gases. I don't see anything but who the hell knows what it would look like or what it may have been replaced by. I was hoping someone else has had this issue. The exhaust used to be clean burning but something prior cat started to go bad.

Your posts are a little hard to read.

Other than the smell and the CEL the car is running ok?

Car runs great but that code is preventing it from passing inspection. Recap, at about 53K CEL came on with 420 code. Suggestions came in to replace the cat and change out plugs, wires and ignition coils. I went with the ignition parts. Performance picked up and code reset by me. About two weeks later that same code came back. About roughly 3-4K miles later a strong emission odor started up smelling like burned fuel. The odor got stronger. I was thinking that the cat must not be burning the residual exhaust gases. About 3-4K miles later I opted to change that cat and lower O2 sensor for the heck of it. The cat and sensor didn't get rid of the exhaust odor or 420 code. I've had older vehicles that had EGR valves that stuck and wouldn't open and got similar odors. The local backwoods mechanic was making some kind of intake airflow adjustments but don't know exactly what. He couldn't get the issue cleared. Before I run to the dealer, I thought perhaps someone else has had the same exhaust issues? Thanks

Series 1 has no EGR so at least we have that out of the way.

Like I said before. Aftermarket catalytic's IMO are not as good as the OEM for emission control.

I don't know anything about those O2 foolers other than what I've read on this forum, but it would seem that most of them don't work.
If you can't pass the emission test .. you need a better catalytic.
OEM is your best bet.

Thanks for the input but the question still remains, the odor was there for a few thousand miles before that cat change and was still there after the change. That tells me something started going wrong prior to the catalytic converter replacement. I've read threads here where some folks actually gutted their units and don't get CEL's? When I said EGR, it just reminds me of something I've experienced in the past with older vehicles. I suspected something took its place but with a rotary engine, who knows. Just was wondering if there was some kind of sensor or something I could check with a meter, a hose or line somewhere, etc.

Does your reader display AFR or Lambda from the O2 sensor? Because this is how you tell if it's running rich or not. If you have perfect AFR/Lambda readings (neither too rich or too lean) it will still smell "rich" if the cat converter isn't working. That's why you can't judge it by smell.

The rotary exhaust runs much hotter than a piston engine. As such it requires a special cat converter. . Idling and cruising it's not uncommon for the rear O2 sensor to readout 1650*F exhaust temp. A piston engine cat won't live long at that temp.

However, I think you need to post up a link to what you bought. It seems to me you're confused about what it is you really bought or maybe how effective it may be.

Unfortunately it doesn't. I bought a unit from Amazon for about $250 after reading reviews from other buyers. All had no issues other than a couple installation complaints. I was thinking if I'm going to go through one of these every 50K, why go top dollar. So I had the problem before buying the unit and still have the issue? I've read posts here about people gutting their units without getting CEL's. That's why I thought low end units will be just fine? Looks like I'm heading to a dealer.

If you really want help then please post the link to it

Do you have an OBD reader? Team is right, the cat might be fine and you're just running rich. Or the cat is not fine, you need to narrow it down. If the AFR reading via OBD is 14.7-14.9 at warm idle, and it smells rich, it's the cat. If the reading is above 14 and your short term and long term fuel trims are not near 0, then whatever your backwoods mechanic did to the airflow sensor is playing into this.

Can you clarify what he did, at least? There is no good reason to mess with the airflow sensor input at all.

Running Rich But Smooth
 

Hi Everyone, I recently bought a 2007 RX8 with 158,000km and I've been having this issue of the car dumping fuel, but the car runs smooth no burning oil and it runs like a clock. I can't figure our why it's
burning so much fuel. Every time I come to a stop I can smell the burnt fuel in the cabin. Has anyone had a problem like this before??

It should definitely be burning oil, there's an oil injection system for this. How familiar are you with rotaries? I'd suggest reading all of rx8help.com to get up to speed.
As for fuel consumption: poor ignition due to dying ignition coils is one common issue. Coils start to be a risk beyond 45,000km, change them preventively. There are no symptoms, it'll still run fine with a dead coil, depending on which one it is. The other thing is catalytic converter getting clogger (usually due to poor ignition). Both of these issues will kill your engine if allowed to continue.

IS the check engine light on and are there any codes?
Where are you located?

I'm located in Vancouver Canada
Check Engine light is present (Code Reading) Catalyst System Efficiency Below Threshold Bank 1
I took it to a mechanic and he said it's O2 Sensor, so I replaced the O2 sensor and the check engine light went off for a day and then it came back on.
I have owned an RX8 a while back. I haven't experienced anything like this before that's why I'm asking the experts.

Ah. Never go back to that mechanic again. Sounds like you need a new cat, or at least to have a look inside your cat to evaluate it. Is there any reason to believe the previous owner gutted the cat and what you're smelling isn't so much rich as untreated exhaust?

What kind of fiel mileage are you getting in L/100km?

Currently, I am averaging about 22L/100KM.

I've only owned the car for a few months. I asked another mechanic, and they stated it could be a cat.

Is it possible that it is more serious than a cat?

The car runs extremely smoothly, and I phoned a rotary shop near me, who stated it shouldn't be running smooth if it's the cat is bad, and that if I fail to address the issue correctly, my car could catch fire.

Jesus. It should be half that if there's highway driving involved. Go see the shop, have them diagnose properly. This is beyond troubleshooting by phone.

You could look under the car after a drive and see if the cat is glowing.

Is the car stock?

Car is stock

I'll check tonight and see if it's glowing.

Thanks for your help. I will update the page once I get an answer from the shop.

I took the RX8 to a shop near me and they checkout the cat and it turns out there is no cat.

Without a catalytic converter could that alone result in fuel economy of 22L/100km

No it shouldn't affect fuel economy.
Not sure if you mentioned already, have ignition coils wires and spark plugs been replaced in the last 20k miles? If not, I'd do that. Absence of cat means someone gutted it, potentially because it was clogged due to poor ignition.

Previous owner stated it was replaced, but now that you said that I will replace them, also there is a ticking out coming from on top of the engine bay.

Could that be related to bad ignition coils / spark plugs?