Looks like I need a different matfactor / thermfactor (and maybe airdensfactor too)!
LCD displays -24..-26C air temp instead of -6 .. -8C
The full vems.hex must be uploaded, but only the first part will be changed, 0x0100..03FF
Do you maybe have new tables ready ?
yes i have new tables ready,but i will have to change the whole thing tough,i realised that for proper everyday use i need more VE resolution on the lowboost section,so i have to change the brake points for the VE table.
any update on these??:
-MAT rescale
-MAT ignition retard
-custom oil temp/pressure gauge with V3.3 and LCD
-5 coil tach?
MAT - airdenfactor
At 0 Celsius the displayed MAT is -16 Celsius. Therefore the ECM enriches appr. 6% (as it should, according to the gas-law), this must be fixed.
We really do not want to hack by raping the gas-law. Instead we fix it the proper way, with proper matfactor and airdenfactor tables. See EasyTherm. Note the recommendations for you in factor_notes.txt, I'd use 3000, 270 (NOT 4200,270 that might be tempting to get +29F at very low temp, but that curve would also effect your high-temp reading, and not match your appr 3000 Ohm sensor). It's basically impossible to know the precise parameters without a measurement near 80..100C.
When
- -16C (3F) is displayed, internal 43 (0x2B) value is read from adcread position 230.5 (actually, 230=>0x2C, 231=>0x2A)
- however, it should read 0C (32F, internal 72=0x48, which could be read from adcread 201)
This is huge difference (255-201)/(255-231)= appr. 5/2 (*2252 Ohm), so likely your sensor has quite greater resistance than 2252 Ohm.
In this case only this 0C datapoint is just not enough to get good calibration result (it's possible to make it show good at 0C, but we don't want to hide bad readings at higher temp!)
Can you provide another measured data-point ?
Either resistance or temp-reading at known temp.
Should i put the MAT sensor in 100Celsius water??
This would not damage the sensor, the MAT might not be insulated, so it can cheat the measurement.
All i can do is that i put the car in the garage ,where airtemp is approx 18Celsius.
That's nice. Also, at every calibration temp-point (0C and 18C, and maybe 35C when holding in your hand), take note of LCD reading, and preferrably sensor resistance (measured with DVM, sensor disconnected).
The sensor is a regular GM style airtemp sensor,like this one here:
http://www.034motorsport.com/product_info.php?cPath=23_30&products_id=58
Note that these measurements are taken in garage,not in a laboratory,i do not have a special equipment for this,80C measurement was made with boiling water.
Temp in Celsius
Real / LCD / DVM (kOhm) / DVM position / NOTE
0 / -16 / NA / NA /
5 / NA / 5.93 / @20k /
18 / 08 / 4.41 / @20k /
21 / NA / 2.92 / @20k /
35 / NA / 3.17 / @20k /My hand,real temp NA
80 / 77 / 0.322 / @2k /HOT water,real temp NA
100 / NA / 0.200 / @2k /Boiling water w/ bubbles
The 100C point suggests an appr 3000 Ohm sensor: 200 / 152.75 * 2252 = 2948.60