I've had the Check Engine light come on with my 2007 RX-8 twice now. Both times, I've taken it to the deal and have had the catalytic converter replaced. It was under warranty, so at least it was free, but what would cause this to happen? The dealer said it is often caused by not letting the engine warm up before shutting down, though I always make sure that the engine is fully warmed up first. I do drive a lot under 2k RPM (an awful road where you can barely get above 40 mph) - does the engine need to rev higher? Is there anything I can do/not do to keep this from happening?

Cheers!

-Erik

 

I just went threw my first one at 19,800 miles on my 07. I went to put in my new catless midpipe and on the way to the shop my cat went out. So I was kinda forced to put on the catless pipe. I'm gunna take my car back to the shop to put the blown cat back on so I can get a new one under warrenty then go catless again. Then when I need a smog test just swap pipes for a few hours. Lol.

Idk what would cause you to go through 3 cats by what your sayin. If you were running it hard it would be different. Hmm.... It maybe your car is running rich and may cause the cats to go out sooner. Idk.

-Ryan

 

I'm not sure, but I think CATs go for the most part because unburnt fuel gets in there and/or you just have a lot of carbon build up.

I'll assume............You don't or never have flooded the car?

When you say this..............."I do drive a lot under 2k RPM (an awful road where you can barely get above 40 mph)" What gear(s) are you in?

You need to take this car out more often and redline it.

 

Should try to red-line it. Helps burn the carbon out of the engine/stop the buildup on the cat.

 

How often do you redline the car?
IMO 2K for a long amount of time without a redline or jump in rpm is not good. How many miles do you drive at this rpm?

 

+1
2K is pretty low to stay around.
I usually cruise between 3.5K and 4K and try to redline (or close to it) during accelerations from a stop.
There are times when I just press on the clutch pedal and hold the RPMs at 8K for a few seconds while on a good straight road.

 

Is there really a point in revving it high without any load?

 

^maybe for teh fire

i dont see why people hold the clutch in and rev it

 

Why not?
What is load going to change?

 

red lining does help but if you try to make it pop it will destroy the cat and make it go out faster.

 

catless FTW

 

Not sure, an expert should chime in. I've just heard that without load, high RPM is useless..

Could be misunderstood on my part, however.

 

Haha +1 dozer!!!

 

You need to get the exhaust temperatures up to keep the cat from being fouled- the only good way to do this is a few long hard accelerations to high RPM under load, although extended freeway runs tend to help.

 

Hi everyone! Thanks for your replies. I drive the car to work about 29 km and the speed limit is around 65 kph, I usually have it in 6th, but there are lots of stoplights, slow people, etc. (isn't everyone slow when you're in an RX-8?). So, maybe I need to take it out on the highway more often and get the RPMs up. Thanks!

-Erik

 

So 40mph in 6th for us backwards yanks, yeah, way too low. That speed is generally 2nd, MAYBE 3rd for me. Heck, you could technically still be in 1st. 4th would be the absolute highest I would be willing to be in at that low speed.

If absolutely nothing else, I am sure you manage to be the first in line at some of those stop lights. Full throttle up to redline in 1st puts you at the speed limit. You can give the 8 quite a healthy workout (or wankle spanking as some call it), in just 1st and 2nd gear without causing legal issues.

 

What do you get for gas mileage?

 

~19 on average. My highway is 21-23, 24 is the best I have seen. 100% city drops it to ~17-18 or so. The lowest I have ever seen was 13, and that was nearly a full tank of nearly constant thrashing in on backroads for several hours one night.

 

Does Mazda cover their cat's with a warrenty? I asked my dealer and he said it's one year, but I thought I read a thread where someone mentioned the warrnety being a number of miles.

Does anyone know what it is?

 

^.............It's 80k miles Dave, and as Al just reminded me...........it's 8 years as well.

 

US Federal Law is 8 yrs/80,000 miles on the cats. The rest of the emissions system follows the regular car warranty.

 

I wonder does that vary internationally. I'm way over in Ireland so things might be different.
Do you know of any reference material I could check on Mazda's site or something similiar?

 

Ouch.......that might make a world of difference. I'm not really sure?????

 

Dealer is telling me 1 yea. That seems very short. I'll try ring around

 

you must not have been having a good day back then
timing, fueling, and in result all the thermal stuff involved in burning gasoline


what mods/maintenance are folks doing these days?

my regular commute is ~25km. 15km of it is city, 10 hwy. i get 18-19mpg regularly, and i usually stay well into triple digits on the hwy and in mild load in the city driving. my most recent test of HWY milage was around 26mpg. relevant mods are: a gutted cat, AP w/MM tune, BHR coils