ilovemy8

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

Red Devil

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.

StormyWankel

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...

ilovemy8

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??

Hoss

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.

dillsrotary

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.

ilovemy8

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!

Hoss

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.

ilovemy8

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

ok good.. thanks!

ilovemy8

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

Red Devil

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.

elysium19

iTrader: (1)

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.

Hoss

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...

zoom44

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.

Red Devil

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.

Hoss

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?

ilovemy8

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!
















*

Hoss

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

Rote8

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

Red Devil

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.

rotareriot

iTrader: (1)

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

ilovemy8

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!

swaze7

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.

swoope

iTrader: (5)

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

ilovemy8

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 ******* 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!

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