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Yet Another High RPM Flutter...

Old 07-14-2012, 01:59 PM
  #51  
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so i think we have ruled out a vac leak..... especially if my car runs fine on a gradual pull.

The numbers are rediculous though. damn thing leans out hard to stoich when i do a hard pull.
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Old 07-14-2012, 02:21 PM
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The TPS numbers look normal. Your gradual pull looks semi-normal. Your WOT is mostly too lean. The 6830 rpm line it is okayish, for example, put it looks to me that for some reason the PCM is getting pulled toward the top (light load) part of the fueling table. I'd suspect it was tripping into closed loop, but your stft remains zero. I still think your maf is ready crazy wrong. This will cause calcLoad to be wrong, at least 10% high at 7k rpm. This will mess up a bunch of tables, including the mysterious 'closed loop a/f table A' which has a direct effect on all fueling. Perhaps repeating the pulls while also logging cLoad would be useful.
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Old 07-14-2012, 02:24 PM
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See what happens if you create a vacuum leak, watch you O2 senser readings.
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Old 07-14-2012, 02:25 PM
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Another possible test is to temporarily disconnect the *rear* O2 sensor, which generates a phantom fuel trim and serves as a backup to the front O2 sensor in case it fails.
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Old 07-14-2012, 02:37 PM
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I am out at a buddys shop now. Gunna swing by Mazda and see if they are open and pick up a new Maf for *****....
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Old 07-14-2012, 03:58 PM
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It's really odd. At 7k rpm, your maf is 11% higher than mine. However, you still have a +5% ltft. CW to zero that out would have you scale the maf calibration by that 5%. That would mean you'd have an even higher maf reading than mine ... by 16% (and mine is already scaled up by 6%, which would put you above stock by over 20% which is huge!).

Yet if the maf is simply reading too high, the PCM should be get feedback from the O2 sensors that it's injecting too much fuel, and the LTFT's should go negative! A contradiction.

Ignoring for the moment possible links through calcLoad, you would have to have both a messed up maf and O2 sensor for this to happen.

Of active members, probably Oltmann has the best grasp of how the PCM works. I realize the SII PCM is different, but perhaps there's enough of an overlap for him to figure out what's going on. Perhaps pm an SOS to him?
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Old 07-14-2012, 04:16 PM
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i will send him a note. And just as an FYI, a new MAF did nothing
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Old 07-14-2012, 04:19 PM
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Seriously disconnect your coolant plug and connect it again. If its loose its going to **** up your computer and go into walk mode. http://admin.sgpetch.co.uk/admin/sys...Tank_large.jpg ( just so you know what i mean when im talking about coolant plug) I plugged it in and havent had a flutter yet, I went 700km in two days just to make sure. its insane how it seem to be my issue, another good possibility is that your plugs are not in straight and tight, some people tighten there plugs by hand and think there is enough tourqe when its a good possibility they are not secure enough.
Sorry for the run on sentance
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Old 07-14-2012, 04:22 PM
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I just can't fathom why that would have any bearing on the car's operation, but I will give it a shot because I am running out of options.
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Old 07-14-2012, 04:59 PM
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Originally Posted by paimon.soror View Post
i will send him a note. And just as an FYI, a new MAF did nothing
Crap.

Are your IAT, OAT, and coolant temps reading about right? Those plus barometric pressure are also used in PCM calculations.

This is the stock "Closed Loop a/f Table A". It seems to be a fueling multiplier which applied to the fueling tables, and is based on rpm vs load. The 5500 rpm column is applied to higher rpms too. Notice several sharp transitions of ~10%. When I try to smooth of move these edges very much, I can get exactly the bog you describe, but in an rpm range that depends on what I'm messing with. If the maf is somehow wrong then the calcLoad is wrong and you may fall off the cliff at the wrong place.

If you're getting 14 with the 1.01 multiplier, you'd be getting 12.9 with the 1.10 ....

"Oltmann, spill in aisle 8, Oltmann, aisle 8!"
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Old 07-14-2012, 05:41 PM
  #61  
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I'm confused,
How did you go from such a rich condition in those first logs to running so lean?

I'll be honest (I know you where in a hurry) I had a hard time looking at that log you just posted.

Too bad about the maf

You could always try unplugging the O2 sensor and see what happens
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Old 07-14-2012, 06:08 PM
  #62  
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Updated the spredsheet so it is more readible

Gradual pull:
https://docs.google.com/spreadsheet/...WxpNWEtckZkVUE

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

WCS;

Front or rear O2? Rear O2 was recently replaced with a new one fyi. It is crazy, the slow pull shows my AFRs gradually getting more lean as I increase RPM, which I think is normal. The hard WOT pull runs up the AFR to rich, then eventually leans out to stoich HARD. I dont get it, the only difference though between the two pulls other than the AFR anomaly, is the MAF readings.....

Digger;

I got your PM, I will have to message you when I get home to see what you want me to do.
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Old 07-14-2012, 06:31 PM
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Originally Posted by paimon.soror View Post
Rear O2 was recently replaced with a new one fyi. It is crazy, the slow pull shows my AFRs gradually getting more lean as I increase RPM, which I think is normal. The hard WOT pull runs up the AFR to rich, then eventually leans out to stoich HARD. I dont get it, the only difference though between the two pulls other than the AFR anomaly, is the MAF readings.....
The more fundemental difference between pulls is the caclLoad. The main a/f lookup tables are written as load vs rpm. When I'm logging to tune, I'll do four log runs from as low an rpm as possible to as high, trying successively to hold the load at 30% 55% 75% and WOT (up to 100%).

The maf may be the same at the same rpm, but if the calcLoad is different, it will fuel differently.
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Old 07-14-2012, 06:37 PM
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Makes sense. For what it is worth, I didn't log it but if I do a gradual pull....then at 6k mash the throttle, it goes to 7, flutters and loses power hard for a second, then continues up the rpm band no problem. Maybe it was a fluke, but I need to try it again to confirm. Not sure if that adds any value
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Old 07-14-2012, 09:55 PM
  #65  
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alright, anyone having a hissing noise near the alternator? I am talking a little bit behind the alternator, but in front of the oil filler tube. I cannot tell if it is coming from the alternator or if there is a magical vac line down there that I didn't catch.
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Old 07-14-2012, 10:20 PM
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^ Do you have one of these? It's a big help in isolating locating souces of hissing.

Northern Industrial Mechanics Stethoscope | Automotive Diagnostics| Northern Tool + Equipment
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Old 07-14-2012, 10:21 PM
  #67  
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i dont but I can probably get one at harbor freight tomorrow
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Old 07-14-2012, 11:06 PM
  #68  
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Alright, so after sitting and reading all freaking day, The only things that seem to be common across many cars/ forums:

1. Bad fuel pump (only 16k miles on the car, this has been happening for a while now, lets say at least since 10k, i would have thought that a new pump would not fail like this, or fail more over time?)

2. Bad primary o2 sensor (quite possible right?)

3. Boost leak (hehe, i wish)
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Old 07-14-2012, 11:30 PM
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What kind, if any mods did you do 10k miles ago?

Yes, I have a vacuum,hissing sound.(see clamp with green tracer)



Fuel line pressure

375-450 kPa {3.83-4.58 kgf/cm2, 54.4-65.2 psi}

Fuel hold pressure

200 kPa {2.0 kgf/cm2, 29 psi}
Attached Thumbnails Yet Another High RPM Flutter...-scan_pic0010.jpg   Yet Another High RPM Flutter...-rscn2753.jpg  

Last edited by Digger1911; 07-14-2012 at 11:36 PM.
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Old 07-14-2012, 11:40 PM
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Honestly, only thing I did back then was suspension mods. Coilovers, sway bars, etc. I also did remove the baffles from the stock intake box (but I kept the screens in). Gauges were also installed, (water, connected to the top radiator hose) (oil pressure, connected to the oil service port) (oil temp, at the oil pan).

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Old 07-15-2012, 12:49 AM
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At any point did you use a RTV Silicone Gasket Maker that
was Not sensor safe?( MAF, O2 ) If yes, change front o2.
How about the carb and brake cleaner you use. sensor safe?
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Old 07-15-2012, 01:01 AM
  #72  
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Originally Posted by Digger1911 View Post
At any point did you use a RTV Silicone Gasket Maker that
was Not sensor safe?( MAF, O2 ) If yes, change front o2.
How about the carb and brake cleaner you use. sensor safe?
Never used RTV on anything, never used carb or brake cleaner on anything before yesterday (carb cleaner to help find leaks, and yes sensor safe)

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Old 07-15-2012, 01:45 AM
  #73  
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Alright, another question that goes back towards vac leak.

I understand that rotary engines pop a bit at idle .... but how much is normal?

Sometimes I will be sitting idle, and the car will just pop pop pop, pop,.....pop.....with a very slight dip in rpm.
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Old 07-15-2012, 10:26 AM
  #74  
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Just for funny ha-ha's... doubled checked to make sure the front o2 was not loose and seated properly. No issues there.
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Old 07-15-2012, 01:02 PM
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Might be on to something here .....

Look at the VAC difference in these two lines .... normal?

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