In Megatune it is second from the bottom in the "Advanced" tab. Its called "coolant-Related Air Density" Once it is open the settings tab will let you change it from coolant related to IAT sensor related. Good luck, I am still stumped...........

BTW I heard from DIY on this issue. They advice me to simply add cold idle enrichment. Not so much at the wizard screen but the other one... I think it is called Start up Enrichment Settings AFTER I tweak my VE table.

I also have a big voltage spike that they pointed out on my log :crx:

SELECT map, mat, round(avg(gammae)) as gammae, round(avg(gair)) as gair, avg(PW) as PW,avg(PW / (gair/100)) as cPW, avg(o2) as o2 FROM data WHERE map > 40 GROUP BY mat, map having COUNT(1) > 10 ORDER BY map, mat;

map mat gammae gair pw cpw o2
41 11 112 112 3.581 3.197 0.963
41 12 112 112 3.531 3.156 0.896
41 14 111 111 3.492 3.146 1.017
41 49 104 104 3.384 3.254 2.876
41 50 104 104 3.359 3.23 2.856
41 53 103 103 3.386 3.287 2.798
41 54 103 103 3.3 3.204 3.012
41 56 102 102 3.312 3.246 2.856
41 58 102 102 3.311 3.246 2.818
41 61 100 101 3.334 3.301 3.168
41 62 100 101 3.258 3.226 2.92
41 64 101 101 3.27 3.238 3.002
41 67 100 100 3.32 3.32 3.134
41 68 100 100 3.253 3.253 3.133


So what you're lookin at is me putting the results of 5 datalogs into a database and pulling out some aggregate data. I added a linear regression to the corrected pulse widths column in excel and got a slope of 0.008 so basically flat.. Shouldn't that mean that the O2 (rightmost column) jumps down considerably even though it should not?

I guess i'm baack to my original thoughtt that the airdenfactor is just too agressive (even though it seems to be right with respect to the formulas), and i should just reduce its effects??
-Tomaj

Not to be outdone I went to the After Start Enrichment Data on my Current MSQ and found the following settings.....

Note that I have never changed any of the settings so this is a big WTF ! for me
Bold numbers are what the settings should be as per the Base tune MSQ that came with the PnP MS.

Bold are the base tune settings

ASE Timer: SEC
ASE Total Time: 60 30
ASE Mode: Fixed then Decay
Map Mode during ASE: Fixed Map
Use Fixed ASE/MAP when collant temp below: 11 degrees 80 degrees
Fixed ASE/MAP Time Period: 47 5
Fixed MAP value 58 80

Right column are the base MSQ settings

After Start Enrichment Table %
47 55
51 50
51 45
50 40
50 35
51 30
55 25
56 20


What do you guys think ?

poobs, i would just use the base MS settings and then adjust from there.

For my part, i've devised an interesting experiment which i think conclusively proves SOMETHING.

The method for my test was to create set IAT correction to 100% for all temps, then to zero in the MS's idea of the right temperature by setting the following values (for example)

Temp / Enrichment
15 100
16 50
40 50
41 100

If the car starts to stutter, you know the MS's idea of IAT is between 16 and 40...
At 28 degrees displayed temperature, the car would stutter and lean out if I set the enrichment to 50% at 11 degrees, NOT 28 degrees..

I sat in the car for half an hour as the IATs slowly rose, and wrote down a table of the temps displayed vs. the temps entered into the IAT table which caused the lean condition.

I was able to record over a 22 degree range, that the difference between the displayed temperature and the megasquirt's idea of the correct temperature was off by 17 or 18 degrees..

1st column -- Temp displayed by Megatune (more or less correct i think..)
2nd column -- lower bound temp of 50% enrichment area in IAT corr. table
3rd column -- difference between the two.

FWIW - Weather.com says 30 degrees.

28 11 17
30 13 17
32 15 17
33 16 17
34 17 17
35 18 17
37 19 18
38 20 18
39 21 18
40 22 18
41 23 18
42 24 18
43 25 18
44 26 18
45 27 18
46 28 18
47 29 18
47 30 17
48 31 17
49 32 17
50 33 17

So the question is -- how do i correct it?

EDIT: Would this be explained if I had this built to be used with AFM but then switched to no-AFM? I never re-flashed after the change..

-Tomaj

ctxspy

What screen shows these numbers ?

Temp / Enrichment
15 100
16 50
40 50
41 100

Is it the after start enrichment screen ?

My intake and coolant temperatures seem to follow a seaprate remote thermometer and the dash mounted coolant temp gauge

Are you using the correct firm ware ?

The firmware for the GM IAT has changes to accomodate for the GM sensor...

Did you contact DIY with your findings on the temperature discrepancies ?

i had my MS built by Braineack, so I can't cry to DIY unfortunately :)

To see the settings i was talking about, go to Advanced -> Coolant Related Air Density.

In there, i had mine set to corrected for IAT not coolant.

-Tomaj

I would be VERY surprised if they don't help you. They are really good people.

At worse they would send you a link of where to read for your answer...

Some more wrenches into the works ---- My initial timing settings somehow dissapeared so I was running with the timing set back (retarded )
I timed the car again saved the settings to the MSQ and will start again with the cold idle settings when the motor cools off again.:jerkit: