Ross Svensson-Hornbostel

The all of the sensors are clean. I'll pick one of those readers up, but I can't really give you readings at idle because it doesn't idle :p
And yeah no doubt about getting proof of compression! I thought I did but looking back on it, the pictures he gave me could have easily been old or just plane fake since I didn't ask for a timestamp and the motor was all ready pulled when I bought it. Owell, live and learn. My dad's buddy at the Mazda dealership might be able to get us a working rotary compression tester it it comes down to it bit hopefully the data I get will get to the bottom it

Edit: what would be the best way to gather readings since there is no idle? Just try to hold it at 2krpm?

RotaryMachineRx

iTrader: (1)

^ That's a good question. Any information would be better than nothing but I'm not entirely sure how skewed the results would be by holding an RPM with the gas pedal. If you could hold it around 1000rpm that would be better (closer to idle RPM).

Unfortunately it being an engine installed by yourselves throws a wrench into things making it really hard to determine the underlying problem.

Lightninglarry

Had my 07 rx8 which has 115 k on it for 3 years. When i bought it i replaced coils and wires and plugs. Never had issues with it till this week. Died on me 4 times at lights signs where im idling. Hooked a cheap cpu to it for codes....none popped. Engine light is not on. Pretty generic with my issues. Took it to a shop and let them try to find it. They said they drove it 3 seperate times and it never died so they couldnt find anything. Upon leaving shop at a light.....dead again. Any help?

UnknownJinX

Do you have any fuel trim data? Could be a vacuum leak.

Lightninglarry

sorry not too savvy. How can i do this?

UnknownJinX

If you have an OBD2 reader that can read live data, then you could look at your STFT and LTFT. If they are very high, then you have a vacuum leak and that can cause stalling at idle.

Some of the Bluetooth ones are capable of reading live data and can connect to your smartphone with the Torque app.

scottish

iTrader: (1)

Oh Lord UnknownJinX and Loki you guys have got to give up trying to help people with there issues by saying Hmmm a Data log would help better to diagnose.

The reason why these people ask for help is because the don't know how to fix cars in the first place and your asking for Data Logs. lol

Have you guys actually owned anything else other than your 8s?
Are your 8s your first cars and your fresh out of high School?

I suggest you guys go and read up on the stickies and study the FSMs and TSBs before offering any more advice on how to fix cars.

scottish

iTrader: (1)

Hmm three years since you replaced them. whats the mileage on these coils?

Is It Hard to turn over after it stalls out?

Hot and cold Start issues?

Get a rotary specific compression test performed.

Check your air intake, screen is present and filter is installed correctly.
clean your MAF.
clean your ESS.
You may have to revisit your coils, plugs and wires again depending on the mileage on them.

And last but not least and what I consider the next most important thing next to the coils, wires and plugs is the fuel pump assembly!!!!
yours has a 115K miles on it.
Replace the pump if your compression test comes back good needs it anyways because there is a non serviceable fuel filter in there that everyone doesn't even think about.

Keep us posted on what fixes it.

Good luck.

UnknownJinX

Okay, that's actually some good advice.

Sorry man, your approach works.

Should probably keep some basic things in mind...

To add, make sure everything in the intake is connected correctly, and make sure the accordion tube is not cracked.

UnknownJinX

To answer your question, no, my 8's not my first car, but I am definitely not as experienced as you are, and you know what you are talking about, so I will listen to your advice of checking for common causes of a problem first before acquiring numbers.

scottish

iTrader: (1)

Yay! finally some one has pulled out the FSM and found chapter 11.

Lol No I don't throw random parts at an issue.I fully investigate what the issue maybe using all the info I can find and I carry out the basic tests first that can be done with basic hand tools but if I have aftermarket parts then I keep the stock ones for diagnostic purposes.

Question does the FSM say anything other than to check what DTCs that have been clocked and nothing about Data logging AFRs and fuel trims to pin point exactly what component in which system that has failed? No.

So when you see that list for multiple types of failures do you just cry and say screw it and just go straight to doing endless Data logs and don't want to get your hands dirty.

Funny thing too is the PCM will try to correct any incorrect combustion conditions within a certain + or - % of what it should be. So its giving you out of whack values anyways telling you what to much or to little fuel hmm problem somewhere in the fuel system, to much or to little air hmm vacuum leak or blockage somewhere in the air intake system, Timing,no spark or not enough spark hmmm problem in the ignition system. well that narrowed it down to one or all of the 4 systems that gets the engine to run.

Pro tuners and engine builders use Data logging to diagnose way more complexed systems than a simple engine of a production line and then again they check the basics first.

At the end of the day an engine is an engine since the day it was invented the fundamentals haven't changed other than now we have fancy electronics running the show but an engine is still an engine and that includes rotary too no different than pistons. Basic fault finding skills.

You Don't see Mechanics reaching for Data loggers they reach for Dtc code readers and fancy specifically made ASTs and the FSM to assist them with diagnosing problems and if they can't then they call in to their tech centres for further support.

You do know the list is a flow chart of yes and no's of multiple issues to direct you to what component that may or not be causing the failure.

LOL You can probably pick off about 70% of that list just by checking the basics that I have listed on other recent posts of mine and fix 99% of the problems people are having and if not then move on to the next step it tells you to go look at it.

You and Loki should both try reading through that whole chapter from start to finish and you might be able to assist someone with there problem faster and more accurately.

Yes I do have a Cobb Accessport and to be honest it lives in the glovebox now just incase I have to take my tune out or I need to check a code. Don't bother with Data logging anymore but only if I have issues at the track and my tuner requests it.

We all drive rx8s on this forum and we all have the same issues how we describe these issues doesn't make the problem any different from anyone else.

UnknownJinX

I hear you, sorry about what I said.

Yeah next time someone/I encounter a problem, I will follow through the Service Manual and try to troubleshoot with that. Thanks for the advice again.

scottish

iTrader: (1)

No need to apologize we are all trying to help each other and maybe we may learn something new along the way.

Redghost025

Sydo

What's it doing at idle ?

Redghost025

TheReliableRotary

What I did it I put a super concentrated fuel injector cleaner fuel additive then when we drove we kept it at at least 2000 rpms until everything warmed up then when warmed up we accelerated and got the revs to at least 6000 best to get it to 7 or 8 grand in first then red line in second if possible and run at high rpms for at least 5 minutes then when you are done before you shut it off let it run idle if it stalls you will need to drive some more at high rpms then once it idles fine what I typically do so it starts easy is rev to at least 4 grand if not higher then turn the key off to expel any extra fuel

Shawn12345

Hello RX8 fellows,

I will start the story with my solution for the eager souls.
Drilling an 1/8 inch hole in the throttle plate solved my RX8's hot idle stall problem.
Now for the rest of the story..
Bought a good RX8 from an guy 10 months ago but 2 months ago and had a massive oil leak on the road. Pulled over the moment I saw the oil pressure meter dropped to zero pressure. Had my car towed to my house. When I inspected the car, I found that engine oil hose had about half inch long rip in it explaining the sudden oil pressure drop I had experienced. I replaced the oil hose and of course the new oil and oil filter while I was at it. Then the hot idle stall problem started. After engine got up to operating temperature, it would start hunting at idle while I was at a stop light. It seemed at some stops, idle would drop too far and just stall out. After trying to educate myself at this forum and other places for a month I gave it to a shop for repair. Mechanic redid all the intake related seal and charged me 1500 bucks but still didnt fix the problem. He told me to come back after check engine light turns on. It didnt happen for 2 weeks. After getting fed up with the lost money and situation, i went to a dealer to get my car diagnosed. Came out with diagnose result that said compression loss and a quote for 7500 bucks to replace the housing and apex seals. I didnt go for the 7500 dollar fix. I paid dealer 230 bucks for the diagnose fee and thought of a way to fix the hot idle problem and live with compression problem instead. By this time I thought I understood the problem well enough to pursue one of two solutions. One is retune the ecu to increase the idle rpm and other is to drill a hole in throttle plate to increase idle rpm. After some more study and cost analysis i went for the hole in throttle plate. Ecu tuning was another set of cost and i would have gone through several retune to achieve stable hot idle. The same goes for throttle plate drill. Hole size has to be a right size so that stable hot idle can be achieved with minimal increase in idle rpm. Last thing I wanted was the car idling at 2k rpm. My first trial was with 1/8 drill bit and it seems to have worked. If I see a hunting in future I plan to increase the hole size by 32nd increment. But then... why such solution? The way I thought was since apex seal cant seal as well as before it would lose some HP. Ok. I can live with 40 less HP maybe but I still want to drive the car. The cold idle is fine because ecu knows to pump extra gas when engine is cold. Theres no problem driving on hwy because you are pumping extra gas to the engine. When engine is hot and is idling, extra gas is not there and apex seal blow by takes power away from the least gas condition that engine cant keep going. A hole in the throttle plate lets extra air into the engine. Mass airflow sensor tells ecu that slightly more air is going in to the engine and ecu adjusts by adding a bit more gas. Its same as slightly stepping on the gas pedal. My car now idles at 950 rpm and its stable and responsive as far I can tell. A brief minute of running the engine dry to pull over after oil pressure loss was what caused all this problem. As for my car's background, its 2004 rx8 that had a new engine installed 3years ago. At the time of purchase the car had 110k miles and engine had 30k. It was a new engine installed from mazda dealership. Car was in a good condition but hose busting almost completely killed it..
There was several engine code. I cant remember all but one. P0172 which is engine running too lean. I almost got misdirected to start replacing parts but dealers's diagnosis save me from doing random things and going nowhere with irrelevant fixes.
I hope my story would be of value for some folks..

Loki

iTrader: (1)

It's a nice hack, but it's not a fix. The underlying problem is still there and will eventually resurface. All you did was raise the idle.

dannobre

iTrader: (3)

Often a hunting idle is the clutch position switch... might be worth a look....

Shawn12345

Yes I agree. It's not a permanent fix. It's a bandage solution I chose to go with instead and yes my goal was to simply raise the idle. My apologies if what I posted made it sounded like a permanent fix. I should have said bandage solution or temporary fix. I did say "solution and fix" and seeing your reply made me realize that it was a wrong choice of word. I want to make it clear this time that I made a choice to go with a bandage solution based on a economical reason. I couldn't justify spending 7500 bucks for the proper fix for a car I paid 5000 bucks for. As for the underlying problem getting worse (further apex seal deterioration and stall or worse) I figure I would wait as long as I can. I am just hoping that it will be many miles later until I am faced with another decision making..

Loki

iTrader: (1)

The thing that doesn't add up is that if you had loss of compression, you typically would also have difficulty restarting the car when warm. I don't know what that mechanic saw, it would be good to get the actual compression numbers, but this may not need a $7500 solution. Like someone said above, hunting idle could be as simple as the clutch safety switch. That problrm should be well documented on this forum..

It could also be poor ignition or vacuum leaks. I can't fathom what intake seals he redid for $1500, it's probably worth asking some questions there.

Jay's_2010_rx8

Hey everybody I'm kinda new at owning rotaries and I have done an extensive amount of research about rotaries and their common issues. That being said, i own a 2010 RX8 with 37,000 miles on it. I installed a cold air intake, a bhr ignition kit (coils, wires, sparkplugs) and a bhr catless midpipe, the engine runs smoothly with no issues, but as i was driving up a hill i came to a stop and the engine started fluctuating between 1500 rpm and 500 and then it shut off on me. I managed to turn it back on and it started idling smoothly again until i went up another hill. What do you guys think the problem might be?

UnknownJinX

What kind of air intake?

Anything that's not AEM/Mazdaspeed, REVi and stock belongs in the trash. And no, not everything stock sucks(figuratively here). OEM intake is already a cold air intake and is an excellent design.

If it's an oiled filter I would check the MAF first.

Jay's_2010_rx8

it is a AEM Cold Air Intake