It started off at 5% but LTFT was still learning and it dropped to a steady 3% at the end of the idle log.

That is not a vacuum leak.



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Dude, you are lost, like really lost ...

Just send me your email address in a PM and I'll tune it for you. I don't normally tune for noobs, but will make an exception because imo you stand to lose more here than gain by trying to handle it this way. Not going to do any troubleshooting etc. for you. It will just be a basic tune specifically for your car, but better than the canned Stage XYZ baloney. Or you can continue here with the tune by clustf-ck committee. Your choice.

 

I'm going to tune it for him, but I can't hardly send a personal email from here(saudi arabis) for some reason. I definitely can't get a file to send even as small as a tune or log.

Ccros,

You should log injector duty cycle, Load, and car speed also. This looks like a first gear pull. If you can log it in a higher gear it will make it easier to look for the stutter. It looks like a rich misfire from my first guess of the log. A 1st-3rd gear pull would help see it over the range. The Idle log looks pretty good to me.

I'm more concerned that you're at 6000 rpm with heavy throttle and still getting STFT. I'm scratching my head a little abotu that.

 

Low compression engine running very weak, there will only be so much you can do

and your logs aren't really usefull without logging Load and IAT is preferred too

But you can pm me or not, not going to continue here ... later



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That's why I wanted to see load.

 

I will try to get a better log posted today. Thanks for the help

 

did you request atr yet?

 

No I have not

 

Ok so i did another log and i went all the way through third gear. I turned on everything just in case we ever needed anything else. By the way, I did obtain ATR.

 

I'm looking it over right now, but an excell file makes things much easier to keep track of what's going on and also post up a 10 second idle log. Adding all the extra things makes it take less data points per a second. you want to run the minimum data points needed. So depending on what you're adjusting you'll have to add and remove things to get the best results.

Your coolant temps were dangerously high when you began this log. Do they stay that high during regular driving? They really shouldn't get that high even under hard street driving.

remove injector pulse, knock retard, maf volts, throttle position, MOP and all 3 timing lines from your logging.

I can see the stutter and loss of airflow and rpm right about 11-12 seconds and at 17.75 seconds on your log. It's at the rich limit of the 02 sensor(this is common on our cars). It might be a rich missfire.

Do you have a flashing CEL?

 

Looks like a sticking intake valve to me, probably the APV.
https://www.rx8club.com/series-i-do-...valves-174009/

If you keep the car >6500RPM after the stutter ends does it still have problems? Will it behave normally until you let the RPMs drop down again?

 

^^fail

I sent an email

 

Amazing how you can figure that out so completely from such brief logs...

 

I'll let those of you who think this is tune related chase a tune related fix, but before I drop out of the thread, I'd point out that he has the problem on the stock tune before he even bought the AP, and then after loading the "stage 1 tune" from the AP, the problem disappeared (almost like it was fuel trims reseting), and then slowly returned.

This tells me that this is not at all tune related, but hardware.

See if you can tune it out though.

 

Good point, and it does throw my guess out too since trims resetting would not have fixed a sticking valve.

 

Please keep in mind, it is also at an extreme power loss. I am running around a 10.3 second 0-60 as I see most people running high 6s... And even when I installed the stage 1 tune, it was still there at first, then it slowly got to the point to where it could rev through the stutter smoothly. But it went back to just how it was before on the next drive cycle. Cleaned the ESS today and that made no difference whatsoever.

 

Looking at the logs you've given, there might be something wrong with your WB O2. The STFT jumps and the LOW then HIGH AFRs when MAF is in the 15-30g/sec range, and that might be a key to the problem. It would help if we had longer logs and in a spreadsheet format with only the important stuff.

 

^ Front O2 was on my radar as a problem to work toward.

There is an AFR problem, and it isn't tune related because it's happening on the stock tune.

AFR problems involving air flow changes are a vacuum leak or an intake valve momentary problem.

AFR problems involving fuel changes are either a physical issue like a leaky injector (Which this doesn't look like at all), or a commanded problem.

A fueling commanded problem can be from a bad tune (not an issue on the stock tune), a MAF problem, or a front O2 problem. (plus a few other very rare ones, like throttle body failure).


I'm not aware of anyone being able to "tune out" any of these issues. Perhaps some in the thread believe they can though. I'd be intersted if they did get it to work. I doubt it's really helping the OP though.

 

Only reason I was suggesting an intake valve was the problem was described as momentary and appeared as a loss of air flow on the logs. I'm still curious why the air flow dropped and then popped up like a cork at ~7500 RPM. Could be from missfires, or might be multiple issues, I'm assuming high highway mileage engine with very little high rpm driving.

 

Agreed Harlan. The remainder of my post wasn't referring to you

 

Pearl, I agree and wasen't trying to tune out his problem. I agreed to do his tune before any problem was mentioned and there is only so much that can be done with a tune while there are other problems with the car.

 

I am not trying to get this issue tuned out... I want to get this issue FIXED, then tune. But I have done all I know to do and am trusting you guys to help me out on this one. And being only 15 years old trying to jump on all of this is a bit hard

 

Then I recommend going back to the stock tune and only using the AP as a diagnostics tool until it's solved, and ignore any offers to solve this by tuning. Once it's all fixed, then by all means, getting tuned is a good idea.


Once back on the stock tune, do another log, and this time upload the csv file to a google docs spreadsheet if you have it, or PM me for an email address and I'll put it on mine and link here for people to look at. The PDF versions are hard to really look through clearly, and with it being not on the stock tune, it's harder to identify things at the moment. The idle log didn't matter, the pull log does.

 

Yes I wasn't planning on trying to tune it out. I really just want to figure out what I can do to fix this issue but I don't really know what else to do and you guys' expertise is really what I'm counting on

 

Well, see the post you quoted, i gave you some next steps.