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Yet Another High RPM Flutter...

Old 07-11-2012, 09:58 PM
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I added another Edit Edit to my previous post.

I wouldn't go above it 7k unless I was testing or thought I had resolved the problem.

But the problem is why are you soooo rich. I'm sure the motor is stumbling due to the rich condition

Check the screens.
Clean the Maf.

Barrow another maf and see what happens.
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Old 07-11-2012, 10:00 PM
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just updated.

I will have to clean the maf tomorrow and then run a test. Well this is worrying me now because it has been doing this for a LONG while. I mean months .... I thought nothing of it though as i thought maybe it was normal.

edit:

So just to try and understand.... suppose the MAF is dirty/not calibrated properly/broken/whatever. It thinks that I am actually pulling ~250G of air @ xyz rpm....to compensate, it is dumping in a LOT of fuel..... other sensors in the car are freaking out at the rich condition, and try to lean out the mixture.... fluttering kicks in. Sound feasible?
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Old 07-12-2012, 12:34 AM
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If the MAF was masked, dirty, or what ever, it would affect all RPM ranges.
Lets say your are cruzen at 4000 rpm, and you stomped on the gas,
it would fall on its face, and bog.

Q: what introduces more air at, in the higher RPM range?

SSV? 16,500 miles, I dont think it is a problem, but I'd have to check it.

""so the fluttering I am feeling .... is that the ECU trying to save the motor from a super rich condition??""



O2 senser voltage needs to be logged.

Side note: after several 4000 rpm to 8600 rpm pulls my exhaust temp max out at 1709 degrees F

Last edited by Digger1911; 07-12-2012 at 12:55 AM.
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Old 07-12-2012, 07:18 AM
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Originally Posted by Digger1911 View Post
If the MAF was masked, dirty, or what ever, it would affect all RPM ranges.
Lets say your are cruzen at 4000 rpm, and you stomped on the gas,
it would fall on its face, and bog.
Yes and no I see your point.
However I had my Maf fail on me driving down the highway.
I would be just cruising along and the car would drop in to 11 afr range and bog down.
Then come back to normal.


It's also easy to check/clean, especially if you can swap it out with another one to see what or if anything happens.

Originally Posted by Digger1911 View Post
Q: what introduces more air at, in the higher RPM range?
Define higher RPM? The SSV on a WOT run is typically open before 4500 rpm.
The VFad opens around 5500 rpm
APV 6250 rpm
VDI 7500 rpm

Personally when I'm tuning I see the largest transition of airflow/calc load/ignition/fueling occur when the APV opens.

Originally Posted by Digger1911 View Post
""so the fluttering I am feeling .... is that the ECU trying to save the motor from a super rich condition??""
No I wouldn't say this. It's doing this because something is wrong like a misfire or bog condition, etc.

Originally Posted by Digger1911 View Post
O2 senser voltage needs to be logged.
You might be on to something with this ... and I'm not dismissing it
My initial thought however is the car will run (Series I anyway) without the Front O2 connected.
As a matter of fact its one of the methods we can use to tune when we want to force the ECU in to Open Loop.
You can then use the after market Wideband installed to monitor AFR's

Anyways (got side tracked there) a failing front O2 could be providing incorrect voltage readings to the ECU

I've not tuned a Series II RX8 (few have), so I'm surprised by the high Maf G/S values at 8200 rpm.
That being said the AFR's shown in those logs are rich. Any weakness in the ignition will show its ugly head. It's a perfect storm for ignition failure, high rpm, heat, rich condition.

Originally Posted by Digger1911 View Post
Side note: after several 4000 rpm to 8600 rpm pulls my exhaust temp max out at 1709 degrees F
Nothing wrong with this is there?
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Old 07-12-2012, 09:57 PM
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Re-posting this here:




Originally Posted by RIWWP View Post
Get an idle log posted. At least 10 seconds.

MAF, STFT are the two main ones we want here. It will confirm vacuum leak or rule it out.

Decimal on the MAF.
Originally Posted by paimon.soror View Post
838rpm, 4G, -14.6, 1.6 ltft, 5.5 stft
822rpm, 4G, -14.7, 1.6 ltft, 5.5 stft
838rpm, 4G, 14.7, 1.6 ltft, 5.5 stft
838rpm, 4G, 14.6, 1.6 ltft, 4.7 stft
800rpm, 4G, 14.6, 1.6 ltft, 4.7 stft
822rpm, 4G, 14.6, 1.6 ltft, 4.7 stft
819rpm, 4G, -14.6, 1.6 ltft, 4.7 stft
822rpm, 4G, -14.7, 1.6 ltft, 4.7 stft
827rpm, 4G, 14.6, 1.6 ltft, 4.7 stft
822rpm, 4G, 14.6, 1.6 ltft, 3.9 stft
810rpm, 4G, 14.6, 1.6 ltft, 3.9 stft
797rpm, 4G, 14.6, 1.6 ltft, 3.9 stft
824rpm, 4G, 14.5, 1.6 ltft, 3.1 stft
873rpm, 5G, 14.5, 1.6 ltft, 1.6 stft
889rpm, 5G, 14.5, 1.6 ltft, 1.6 stft

from yesterday. Dont mind the negative/positive on the afr
Originally Posted by RIWWP View Post
yup, you have a vacuum leak.


Vacuum leaks are most prominent at idle, where the volume of air the engine is using is so small that even the smallest vacuum leak is a portion of the whole.

The engine pulls about 5.5g/s of air at idle (varies a bit by compression I imagine). If air is getting into the engine that is NOT passing through the MAF, your MAF will read low and the ECU won't be adding enough fuel. The O2 sensor will pick up the slight lean condition (same air less fuel) and add fuel in +STFT.


I had a vacuum leak that dropped me to ~4.5g/s with +5% STFT, and it was a really tiny pinched UIM gasket.

Since yours is affecting at a certain RPM, I'd bet that the vacuum leak is in one of the lines running to one of the valve actuators, and it's hurting the effective operation of that valve.
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Old 07-12-2012, 10:21 PM
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Nice
But I still find it curious that there is 250 g/s at 8200 rpm.
A vac leak down low is going to create positive fuel trim and make things even richer up top.

I hate vac hunts
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Old 07-12-2012, 10:26 PM
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Paimon,

Just throwing this in here but did you not renew your O2 Sensor to a generic one?, I can't exactly recall your PM (deleted) but I think you asked the difference between S1 and S2 (Manuals) as Mazda shows them as different, but generic sellers list only one type for all Series RX-8's...incorrect.

I think I said that IMO it was perhaps something to do with wiring and or wiring plug?.

ECU: ALL Resets:..S2
Disconnect Negative Battery Terminal and press ONCE on Brake Pedal WITHIN, 60 seconds.
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Old 07-12-2012, 10:27 PM
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His MAF isn't normalized, so the raw number isn't that useful, and grows further off base the higher it goes. I'd guess his MAF voltage is in line with similar 8s.
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Old 07-12-2012, 10:27 PM
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If you figure this out please
Send me a an meat [email protected] something I noticed with my arm intake is the line to the intake manifold where the vfad use to be snapped off and I had a small leak behind the throttle body. Couldn't find a
Way to cap it. I have the same problem
As you exhausts made it louder of you try to keep it 7k it just bucks and makes it seem that
Much worse
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Old 07-13-2012, 03:19 AM
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1. identify symptom, scan for codes.
2. check the basics, battery, battery connections, body grounds, voltage drop, and alternator output.
3. visual check of engine components, engine compression. Test exhaust emissions reading
CO,CO2, HC,O2, Nox.
4. using an oscilloscope, check the primary and secondary ignition components.
spark plugs, secondary ignition wires, and coil out put under load condition.
5. fuel system, fuel level, condition and quality of fuel, fuel pressure and
volume.
6. open a six pack of beer or a bottle of Jack and think about it.

7. almost looks like it went into open loop at 5700 rpm, stft values quit
changing. The exhaust sounds like an ignition breakdown.
I would be using a scope to decide if the ignition was
going to ****. it's hard to do this remotely because it is usually a subconscious
decision on what to look at next based on what I just saw. waveform, ignition and injection is what I
would like to see. ? A test drive is worth a thousand pictures.
It is not a vac leak.
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Old 07-13-2012, 06:42 AM
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^ STFT values should go to zero and stay there in open loop (series I).

I agree with wcs, the gm/sec seems too high which would result in a rich condition. SII owners may not be noticing the flutter, but many seem to get very poor mileage, which may be related.
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Old 07-13-2012, 09:15 AM
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Originally Posted by Digger1911 View Post
It is not a vac leak.
He DOES have a vacuum leak. Look at the idle data he posted. It's completely clear. Until he solves that leak, chasing anything else is largely pointless


And if the leak itself is in the...Variable Intake Valve vacuum line (assuming that his tach is off), then it would wreck havoc with the valve's operation. Which would be an exception to the normal guideline of "vacuum leaks get minimized as load increases".

Attached Thumbnails Yet Another High RPM Flutter...-renesisintakevalving.jpg  

Last edited by RIWWP; 07-13-2012 at 09:21 AM.
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Old 07-13-2012, 09:33 AM
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Originally Posted by RIWWP View Post
And if the leak itself is in the...Variable Intake Valve vacuum line (assuming that his tach is off), then it would wreck havoc with the valve's operation. Which would be an exception to the normal guideline of "vacuum leaks get minimized as load increases".
Excellent point good sir!

But does it explain the high maf values?

Of course Murphy may step in with "The probability that any two unrelated failures will occur at the same time is ~100%."

Last edited by HiFlite999; 07-13-2012 at 09:38 AM.
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Old 07-13-2012, 10:03 AM
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OK so question, at idle are the solenoid open or closed? I ask because if they are closed, wouldn't it make leak hunting by means of smoke or propane difficult as there would be no vac on the line?

Or am I completely off base.
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Old 07-13-2012, 12:28 PM
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I just reviews codes for both cylinders /rotors with this stupid flutter? Car starts with 3 plugs and sounds like a comcutive psst pattern
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Old 07-13-2012, 08:49 PM
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So this is going to sound crazy but..... If your like many, our coolant resorvoir sensors are **** and you keep getting a light. Mazda unplugged the sensor going into my coolant when they did my engine and said i need a new reservoir. I plugged it in today at of curiosity and i havent fluttered once today..?
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Old 07-13-2012, 09:02 PM
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hrmm, doesn't make much sense.

FYI i took apart the upper intake manifold. Checked all lines, sprayed all lines with carb cleaner to see if there was any leaks. nothing, absolutely nothing. Still fluttering.

I have a buddy coming over tomorrow to help look with me, but I am really running out of ideas here.
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Old 07-13-2012, 10:29 PM
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ok well you got me to thinking how my coolant level was. Went downstairs, and my coolant is sitting right on the "L". Odds that low coolant would cause this fluttering??? Not too sure but if you google search "engine flutter and low coolant" you sure as hell do get a lot of hits......
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Old 07-14-2012, 09:48 AM
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Not sure but top it off and then get any air out of the system by letting the car warm up fully with the cap off, then turn the heat on full blast and then rev the engine up and down for a minute or two. When coolant looks like it is going to overflow out of the reservoir then you can cap it.
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Old 07-14-2012, 10:11 AM
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Other than [email protected] this has been the only interesting thread lately

WE DEMAND AN UPDATED PROGRESS REPORT!







OH and bump
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Old 07-14-2012, 10:32 AM
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lol, i am glad my failures at diagnosing a problem is entertaining :p

You will get an update soon. Picked up some distilled water to top off coolant, got a buddy over to help diagnose.

You will either get an update here, or on the news with a headline "Man goes on crazy shooting spree in town, M.O.: RX8 issues"
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Old 07-14-2012, 10:46 AM
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Tanks man
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Old 07-14-2012, 12:46 PM
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Ok here is a doozy.

Whether under load, or at a standstill, if I gradually increase RPMS, no flutter, nothing, smooth as silk.

WOT is where it falls flat on it's face. Here is a snippet of my WOT logs with TPS. I dont have the time atm to filter out the bad data "0's" so hopefully you guys dont mind. Take note that TPS is only reading 78% at WOT!?!?!?!

https://docs.google.com/spreadsheet/...XV6Y1NFbWp4cFE

Last edited by paimon.soror; 07-14-2012 at 04:59 PM.
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Old 07-14-2012, 12:47 PM
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Last edited by paimon.soror; 07-14-2012 at 05:08 PM.
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Old 07-14-2012, 12:54 PM
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My tps reads 79% @ WFO, Yesterday I drove 1100 miles, and avg 22 mpg (San Diego to the Oakland and back to SD)

Last edited by Digger1911; 07-14-2012 at 01:02 PM.
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