Ive had my rx8 for about six months now and lately i've been noticing some interesting sounds coming from my 05 8. I've got a MT with minimal modifications done to it, but I'm trying to figure these issues out before I start toying with her.

Sound 1 - Ticking while driving

At first me and my friend thought it was transmission chatter, because when you accelerate it would sound like teeth chattering from about 2k to 4.5k, after that you can't tell because my 8's exhaust is too loud. I disproved this by revving the engine at idle and I still hear it, not quite as defined, but definitely still present. Could it possibly be motor mounts? or would this be bringing me inside the motor towards the injectors?

Sound 2 - Whirring with clutch depressed

Pretty self explanatory, clutch depressed and I start hearing a whirring sound similar to half the sound of a stock renesis at idle. With clutch released and in gear or in neutral, sound is not present.

Now moving into the things it does...

Idle - Unsteady and low

At idle, I noticed in other 8's the rpm's sit at about 1k, however in mine i'm sitting at about 700 rpm's when it stays steady. But I did notice that it hardly ever stays steady at one set rpm, otherwise I wouldn't be too worried about it. Instead, it revs up to 1.1k down to even as low as 300 rpms, and barely stays alive at that point, but the 300 is very rare. I've run everything from REstore through it to see if that did anything, engine cleaner, injector cleaner, and even changed the plugs to see if it was just a bad plug. No change in attitude of idling rpms. I haven't done a compression check although I know I probably should..

Check engine light - ...

I know what this MIGHT be, but still unsure, while driving the light is just on, and when really riding on her above 4.5k in any gear, the light starts blinking. I read somewhere that having a midpipe on her instead of a cat could cause this due to a sensor reading different than its supposed to, but still unsure about it. Another thing, related to the midpipe, she backfires alot after letting off the throttle after a pull, no matter how long the pull was.

Any advice on these issues would be great, I'm no mechanic, just a stubborn DIY'r, so please any rotorhead gurus give me a helping hand! Thanks!

 

get the CEL read.

how many miles on the car? have you replaced the plugs, wires, coils?

What tranny fluid are you using?

 

40,800 miles, replaced plugs but not coils or wires. will get to the CEL on Sunday, on duty tomorrow as for tranny fluid I havent changed it so I'd have to find out from previous owner

 

I got the codes read, basically my buddy workin at the shop with me said that most of the issues were with the midpipe throwing off a sensor in the exhaust, and that it was causing the ecu to think i wasn't burning enough fuel, so its causing the motor to run lean and it has a misfire in the primary rotor. At least this is what I grasped from the conversation. If this is so, would I be able to just unplug this sensor and the motor would run normally again? Or would changing the coils and wires be a smart idea to do as well?

 

could be a clogged cat, pretty common. pull it off and check it. Search for "Clogged cat", there's a diy that shows you how to check it out and how to gut it if you want to.

 

that would make sense if I didn't have a midpipe and no cat

Something I did notice though, when I take the sensor off of my KN intake, the car idles normally, didn't listen for misfires when I did it I was kinda excited. takin it today to disconnect the o2 sensor and lookin up intake sensors or something like that I guess. new coils inbound and wires too, as for the rattling, still need some help! Thanks!

 

Hello,

Did you ever get this resolved (strange noise)? I am having the same problem myself. At first I thought it was a loose flap but that was not the case. I then thought my engine was going on me but took the car to Mazda and they said the engine was fine. Recently I changed out the plugs and wires and the car still makes the strange noise. Any help is greatly appreciated!!!

Sal
2004 MT, 78K miles