Log File Reporting of 'Desired Idle RPM'

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toliphint
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Joined: Sun Aug 08, 2010 6:35 pm
Location: Montgomery, AL

Log File Reporting of 'Desired Idle RPM'

Post by toliphint »

Anyone know the AUJP $8D code address that's being reported in a TP V5 log file under the heading 'Desired Idle Speed RPM'? Thanks.
robertisaar
Author of Defs
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Post by robertisaar »

what are you trying to do here?

tune out some idle instability?
see if something is commanding your idle higher/lower than expected?
swap out that value for something else?
toliphint
Posts: 62
Joined: Sun Aug 08, 2010 6:35 pm
Location: Montgomery, AL

Post by toliphint »

Thanks for responding. I was attempting to determine why my log was telling me at cold start-up that Desired Idle RPM was only 800 RPM, when my Idle Engine Speed .vs. Temp table was set to 950 at 68*F and 900 at 90*F (my approx ambient temp at start-up).

Since my post, I did a quick test by changing hex locations 426C and 4270 to 1000 RPM, and shazaam, desired idle was immediately reported correctly at 925 RPM based on 88* ambient. So now I know that TP is reporting the RPM from the Idle Engine Speed .vs. Temp Table, as I thought it should.

But now really confused because thought the 800 idle cap at 426C and 4270 was for in-gear only and not for P/N. But my test above disproves that, which seems to contradict multiple posts on ThirdGen. Further, my ECM knows when the selected gear is P/N because the idle increases by 100 RPM per the ECM setting.

Any thoughts? Are the referenced hex locations for in-gear only or for any gear? Almost have to be in-gear, or the Idle Engine Speed .vs. Temp table would be useless at cold temps.
robertisaar
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Post by robertisaar »

i'm not 100% familiar with 8D, but those addresses are way outside of the calibration range for 8D.

8D only seems to use a single idle speed vs coolant temp table, it appears to be for idle speed when in anything other than P/N. there is a scalar used to offset idle speed in P/N upwards.
toliphint
Posts: 62
Joined: Sun Aug 08, 2010 6:35 pm
Location: Montgomery, AL

Post by toliphint »

You're correct. The addresses are not in the calibration. They're in the AUJP code. Here's a link that addresses it:
http://www.thirdgen.org/techboard/diy-p ... 730-a.html

And as you state, the single 8D Idle speed .vs. temp table should only apply to other than P/N (ie - in-gear), but my quick test showed that changing the 2 code bytes to 1000 RPM caused TP to properly report that table in P/N. Never put car in gear. Without changing the bytes to 1000 RPM, the default of the code (800 RPM at the 2 addresses) was being reported until temp reached 136*F, whereupon Desired Idle began to be reported in declining values of 787, 775, 762, and finally 750 at 156*F which is in the remainder of my table. Clearly something was limiting TP's ability to report anything above 800 RPM as Desired RPM. Using super_8dm2.xdf from TP site. Changes to the code were made by modifying the xdf from within TP to access those locations as provided in the link above. Something's not right.
robertisaar
Author of Defs
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Post by robertisaar »

tunerpro isn't the issue. the values reported aren't limited via tunerpro, but rather by the ECM itself.
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