rlawson1980

I have a GT 6 spd with 1500 miles and I noticed a slightly rough idle. Its not bad at all, just noticable sometimes. Does anyone else have this issue?

Thanks for any replies

VTLC

Get rdy for disappointment, cuz Mazda says its normal. Mine does it too but just worst.

Rev It Up

I have owned three older RX7's, and all of them had issues with a rough idel, although it did not seem to hurt the performance. After having my 8 reflashed for the second time with 7000 miles on the odometer it is now showing sings of rough ideling as well.

Kain

I swear to god this was somewhat alleviated when I put on a new grounding cable set- it could have just toned down in coincidence of me installing these, but hey for me my idle is quite a bit better! burn the rubber road to freedom!!!!

jyoji

When I first got my car, I wondered about having a rough idle too (i.e. at stop signs) I just had my car M flashed the other day and I've noticed that the idle isn't as rough, but it's still there. I don't worry about it anymore - I stopped comparing the idle to that on other cars because the Rx8 is a Rx8!

Rx8titanum

I actually had my car hooked up to computer because i was worried about idle. Passed with flying colors. Its normal for a rotary engine, the owner of a Rx7-8 performance shop told me. So I wouldnt worry about it. I am use to sound now

mysql101

What are you guys talking about? The rpm needle is moving around at idle? The car sounds rough? Or are you talking about the stick shift moving around?

Kain

in my case prior to the grounding cables, at idle with the car out of gear, (like at a stop light) the idle would fluxuate betrween about 850-950 rpm, just a little rough.

mikeb

when I start my car in the morning the RPM's hit 3 and then slowly work down to 1 is that normal?

mysql101

mine starts at 2k and works its way down to 1k within 1 minute.

Kain

mine isabout 2500 and works it way down. but only happens when car is not warmed up at all! like the morning- but when I go home at the end of the day, it only does this for about 10 seconds as opposed to the 30 to 60 seconds it does it in the mornings

Bob The Eskimo

This move from two or three k rpms is normal. It is the engine burning through the extra fuel used to start the engine when cool (prevents detonation).

The rought idle is natural for one (known) reason. The fuel injectors are very high capacity. This allows enough fuel to be supplied when you are hauling **** at 9k rpms. That's a lot of fuel injecting. When the car is at idle the injectors are just barelly putting out fuel but this is still too much fuel for smooth running. This roughness dissapears just past 1.1k rpms and therfore a non issue when driving.

All in all, you could solve it by putting weaker injectors in, but then you risk detonation at higher RPM's from lean fuel mixtures, and you could never turbo the engine.

Keep it the way it is. Just think of it as the 8's way of letting you know it is ready to go. Drive it like you stole it.

mysql101

I don't know if this helps any, but here is my car when it starts up.. the last few seconds shows it after it's warmed up.

http://tyrannical.org/rx8/rx8_idle.wmv

RotorMotor04

Good explanation Bob, seems logical

mikeb

I just got worried because it used to go up to 2k but know it goes up to 3k in the morning.

pretty soon it will be redlining when I start it up