Idiling Question

[Renesis]

When i first got my car I noticed it had a bad idle. It would literally kick back in before it died, when I sat in neutral. I took it to the shop and they told me that I had a cracked engine block and within a week i had a reman-engine installed.

I noticed today that my idling is really rough. I sat in a drive thru in neutral and it began to shake more then normal and really sound like it wanted to die. It did it a couple times but always quickly kicked back in. It's hard to explain. But basically it was quite loud and would just go low to high. There are no loose wires nothing missing. I'm hoping that It's nothing major and maybe just something the rx8's do. I was wondering if anyone has the same issues or if this is normal.

[winning8]

I have the AP underdrive pulley and my idle is not consistent since installing it. It could be partly due to it.

[Renesis]

hrm..i'll have to read up on that them. some said a new reflash is out but my vin number doesn't follow with the numbers that the reflash is out for

[I8U]

hrm..i'll have to read up on that them. some said a new reflash is out but my vin number doesn't follow with the numbers that the reflash is out for

Weird, I figured since you have an '05 the flash would be good for you since it is for nearly all 8s from '03-'07. I am also having some idling issues hopefully this flash will fix it since I don't to have to replace the engine again.

Here's the VIN listing for the flash just in case:
2004-2008 RX-8 vehicles, produced from April 10, 2003 through November 9, 2007
• VIN Range: JM1 FE17** 40100053 - 80215462

[Renesis]

Yeah i saw that my vin is JM1FE173550146614
the reflash describes my problem exactly.

I do have an 05 but i don't think my number falls between the ones they have listed. I need an oil change so i was gonna have them do the reflash at the same time. Since the ECU reset i did didn't work.

[I8U]

Jen, how long have you been having problems? Have you had a sudden loss of power? What about the emissions recall, did you have that done?

-Nic

[Renesis]

i've noticed the problems off an on. It doesn't happen all the time just once in awhile and when it does, as the reflash says it shakes violently. I don't know what the emissions recall is. I got my car back in january after they replaced my entire tranny and gears and I had a re-man engine done in october.

[I8U]

The engine replacement must have been done because of the emissions recall. I was in the same boat about 20k miles ago...my problem was the real bad idle also, it has died a couple times but I've had the compression tested and the motor is still extremely strong...so strong infact the techs can't figure out why I'm having so many issues.

Now does the idle drop real bad after a pretty decent drive and come to a stop? Cuz that is what mine does...I thought it might be from the new intake and exhaust I installed but it's been on long enough for the PCM to recalibrate the A/F ratios. So, I'm at a loss now too...well at least until I get the new flash and I'll go from there.

[Renesis]

umm droping i'm not exactly sure what you mean by that (sorry not very car smart i'm learning though) From what i remember I was driving the speed limit, not too hard on the car and was just parked in the drive thru feeling it shake violently i saw the tack on the spedometer move maybe half an inch nothing major but enough to catch my attention.

they re-man my engine 'cause i had a crack in my engine block which caused me to lose compression. I'm going out for the night so i will reply when i get back :)

[I8U]

Dropping, like dropping below the normal idle rpm. RX-8s normally idle around 800rpm, usually anything below that the car does tend to shake a little more noticeably. Maybe your motor mounts might be going bad also, but definitely take it in and have it looked at. Maybe another thing to check is for a lose or disconnected vacuum line on your intake...that could cause a rough idle too. Not sure though, just trying to give some other options to look at.

[Renesis]

yeah we thought it could be the vacuum line but everything seems tight. i notice it kinda bobbled above 800 rpms and back down.

[ScreaminRX8]

Well mine has done this exact same thing on occasion since I had the recall done. No new engine only had a reflash and plugs. Before the recall mine idled around 1000 to 1100 rpms and now it idles around 8 to 900 rpms. I am about to carry mine in for the 30,000 mile service and I am going to get them to check it.

[I8U]

Screamin, 1000-1100 was pretty high, and 800-900 is about where it should be. The norm is 750-850.

[ScreaminRX8]

I8U, I thought so too, even though it idled smoother. Now with it around 800-900 it idles rough at times. I am thinking though after the 30,000 service with the new plugs and all it will run and idle better. I will tell you since I took the cone and baffels out of the airbox it runs and idles better and gets better gas mileage. I figured the reason for that is it is getting more air.

[I8U]

I8U, I thought so too, even though it idled smoother. Now with it around 800-900 it idles rough at times. I am thinking though after the 30,000 service with the new plugs and all it will run and idle better. I will tell you since I took the cone and baffels out of the airbox it runs and idles better and gets better gas mileage. I figured the reason for that is it is getting more air.

Mine ran a little better when I did the same mod but I have recently installed a K&N Typhoon V2 intake and the HKS Hi-Power exhaust...idle seems to be better but I think my coils are going out again. I'll make a thread about that though...that is a pretty long story.

[Herblenny]

I will tell you since I took the cone and baffels out of the airbox it runs and idles better and gets better gas mileage.

Whats this cones and baffels thing?? I'm an 8 newb.. I'm now experiencing so called "flooding" and I hate the 8!!! I want to sell it and pick up an Accord:)

[fikren]

Whats this cones and baffels thing?? I'm an 8 newb.. I'm now experiencing so called "flooding" and I hate the 8!!! I want to sell it and pick up an Accord:)
There are a couple of things you can do phil, not sure which if both they are refering too. There is one mod that you remove two plastic "walls" inside the air box. If you open your air box up, around the hole on the top of the box on the inside are two walls that theoretically can block air. Both walls are held in by two screws. Remove the screws on each side and remove the wall and your done. Opens it up very similar to the RB air box.

You can also remove one if not both of the screens in there also BUT there is some debate on if this is a good deal or not. The screens are there to straighten air flow to my understanding and are there by design from mazda. Some claim it helps but others claim that it has hurt idling.

Idling problems have occured with several types of aftermarket intakes. I think I8U is running the typhoon v2 but if I recall the V1 gave people lots of problems. Has to do with how the air ends up hitting the filter shape and is why RB went with the type/style filter in their setup.

I think there can be arguments either way on wheather to go aftermarket or mod your airbox. I think removing the walls is something that can be done without problems, people say it makes the sound alittle louder so they may have just been there for resonance purposes. I however at this point am not planning (other than possibley the wall removal) to do any type of intake replacement. To me the gains (possible 1-2hp above 7k rpm) are not worth the risks (poorer idle, noise, possible engine warranty void). Hope this helps Phil maybe the others can chime in on what mods they have done or their thoughts on aftermarket intakes or modified intakes.

Edit: you will also want to do an ECU reset whenever you do any mods to your intake.

Jonathan

[ScreaminRX8]

I was refering to the two "walls" as fikren was talking about and the cone is the tube that has a screen in it and when the box is closed it fits fluch against the filter, which has three screws holding it in. Once taken off it looks like a cone. I really can't tell that it is that much louder. The only reason I tried this is for better idling and better fuel mileage. It has definitly helped with the idling issue, but it has only improved my mileage by 1 or 2 miles to the gallon. I will personally re-install these items before I carry it back for my 30k service. Not sure yet if I am going to take them back out after.


You can also remove one if not both of the screens in there also BUT there is some debate on if this is a good deal or not. The screens are there to straighten air flow to my understanding and are there by design from mazda. Some claim it helps but others claim that it has hurt idling.


I am not saying that they didn't put it there by design, some things are designed in because of regulations. If they have to do anything like we have to at Harley-Davidson to meet emission (EPA regulations), things like this are put there for that reason. Companys also have to meet noise regulations and this may be the case for the "walls" in the airbox. I am still learning about the rotary but I would think that it is like any other engine with fuel and air ratio's. On Harley engines you can introduce more air and it runs much better but if you add more air and open up the exhaust is when you need a new ECM flash. The main reason for the flash is the computer is trying to compensate for the extra air and less back pressure. They are so bogged down to meet all of these regulations for the different countries.

[Renesis]

i had to do the ecu reset after i installed my knock off aem ebay intake.

my idle isn't that bad it's just a bit rough but now i have a huge flapping sound in my intake that only happens when i accelerate while driving, not reving and not in neutral.

[praxis1301]

I saw this kinda late... but if you haven't done the reflash...

Yeah i saw that my vin is JM1FE173550146614
the reflash describes my problem exactly.

I do have an 05 but i don't think my number falls between the ones they have listed. I need an oil change so i was gonna have them do the reflash at the same time. Since the ECU reset i did didn't work.

Your VIN does fit in the reflash... urs is 50146614
VIN Range: JM1 FE17** 40100053 - 80215462

[Renesis]

ahh yeah i had the reflash done (haven't been on in awhile) my idling is alot better