ECU Conversions

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Apr 27, 2005 | 10:53 PM

JP86SS

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From: Browns Town

Car: 86 Monte SS (730,$8D,G3,AP,4K,S_V4)

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ECU Conversions

I'm refining the $8D XDF file and am having difficulty getting a handle on some of the conversions.
I borrowed the top list from "Programming 101" and don't have a problem using them. The bottom few are not clear to me.
Can someone assist in getting the list completed correctly?
TIA,

Code:

;  Temperature, Coolant        N x (191/255)-40 degrees C 
;  Speed                      N x 1 0-255 MPH 
;  RPM                        N x 25 RPM 
;  RPM, low range             N x 12.5  RPM 
;  WOT AFR                    N x (100/256) AFR 
;  PE (power enrich)          N x 10  
;  VE (volumetric efficiency) N x (256/100) 0-100% 
;  Knock retard               N x (45/256) 0-45 degrees 
;  Knock attack Rate          N x 0.0225 milliseconds 
;  Knock recovery Rate        N x (500/256) milliseconds 
;  Spark Advance              N x (90/256) 0-90 degrees 
;  Spark Retard               N x (45/90) 0-45 degrees 

These I need clarification on, 
;  MAP                        N = 256 - (Kpa *(256/80)) Values over 80 Kpa are "-" ???
;  MAT Deg C                  N x 0.750000 + -40.000000
;   Same as Coolant ??        N x (191/255)-40 degrees C
; O2 Volts  (milli Volts)     N x 4.440  + 0000 (or should this be 1/256 ??)

MAT Values come out negative on some entries, might be because of the inverse usage in some points.

Apr 28, 2005 | 07:48 AM

RBob

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From: Chasing Electrons

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For the O2 value: mV = N * 4.42, N being the value in the bin. If N is 106: N * 4.42 = 469 mV

For MAT it depends. The most common used MAT term is a linearized term. This will be the same as CTS: °C = N * .75 - 40. Note that the EGR enable and a handful of diag stuff use the inverse ADC MAT, which requires a table lookup.

For MAP it depends whether the SD MAP term is used, or the ADC MAP. I think most of the code uses the SD MAP term. The conversion for that is: KPa = (SdMap * 0.3125) + 20

RBob.