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Old 01-14-2010, 06:15 PM   #21
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My matfactor.inc in the hires/mtcfg directory says:

; Generated using EasyTherm4.exe,
;
; Air Temp Thermistor Comment Field
;
; ***** CAUTION - NON STD BIAS RESISTOR REQUIRED *****
; File generated for use with 2625 ohm resistor at R4
;
; Steinhart-Hart coefficients: A= 1.505975E-03 B=2.249965E-04 C= 1.247472E-07
;
; Input Data: Temp, degF Resistance
; -4 28681
; 86 2238
; 210 177
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Old 01-14-2010, 09:53 PM   #22
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FWIW i set the bias resistor value back to the value you recommended earlier (36XX ohms, too lazy to check atm). The temp came up to at 38 degrees vs 60 degrees with the 2625 bias setting.

I just confirmed again that the resistance at the sensor was correct (4640 ohms at 60 degrees), so i am satisfied (kinda).

The only remaining bothersome problem is that when i try my "advanced->coolant related air density" trick, it still appears that the MS somehow thinks it's 5 degrees off, but that's still a lot better than being 17 degrees off as it was before the reflash..

Scott -- can you try this for me??
1) get the current MAT
2) in advanced-> coolant related air density
3) set one of your temp values to one degree less than MAT noted in step 1, set value to 100%
4) set next temp to MAT, set value to 50 %
5) set next temp to MAT+1 degrees for example, value = 50%
6) set next temp to MAT+2 degrees, value = 100%
(this is to create a vertically sloped area of 50% enrichment)

If your MS is correct, your car should probably stall when u burn that.. right? For me, it doesn't.. I have to shift my temp values by 5 degrees to get it to stall out, which to me indicates the MS thinks its a different temp than is displayed in MT.

-tomaj

P.S. -- is there any way to get the AIRDENFACTOR ADC value as seen by the MS?

Last edited by ctxspy; 01-14-2010 at 09:57 PM. Reason: to ask scott for a favor
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Old 01-15-2010, 09:32 AM   #23
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oh the numbers in that table have never been correct for me. i think they are off by 10*F or so.

I have my table zeroed off until 95*F where I add in some fuel to battle heat soak.
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Old 01-15-2010, 04:01 PM   #24
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lol that never bothered you?

Then again you're over in florida so you probably stay in the flat part of the enrichment curve and wouldn't see the same negative effects that I do.
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Old 01-15-2010, 06:38 PM   #25
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you mean VA. i moved my AIT sensor out of the engine bay so i dont get stupid heat soak issues and dont even really need the corrections table.
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Old 01-15-2010, 08:01 PM   #26
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Originally Posted by Braineack View Post
you mean VA. i moved my AIT sensor out of the engine bay so i dont get stupid heat soak issues and dont even really need the corrections table.
Hey, I always put you in FL for some reason.. Anyways, regarding the iat correction table, even tho you are not using it, the underlying problem is stil there no?

IOW the temp being off is just a symptom, the problem being that the Ms. Rhinks it's a different temp
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Old 01-17-2010, 08:41 PM   #27
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okay, well, I tired those numbers out...the ones I gave you without R4 and R7 and I had issues with the AIT reading about 20*F too low myself. I'll have new numbers to try tomorrow for you.
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Old 01-17-2010, 08:51 PM   #28
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lol the numbers i used seem to be working ok.. it was off by 2 degrees today when i first got in the car, but don't let that stop you it would be great ot have a real fix.

-tomaj
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Old 01-18-2010, 12:55 PM   #29
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what did you end up using so I can try them out today?
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Old 01-18-2010, 01:13 PM   #30
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what did you end up using so I can try them out today?
2625 for both. Seems OK but can't be sure until we see larger overnight temp changes.

tomaj
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Old 01-18-2010, 04:14 PM   #31
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I'll probably check in the morning. I have my MSI united plugged in now that I have had the same settings for 4 years. I know the temps are accurate, it's always right around ambient anytime I check overnight and I've tested the clt temps versus a thermometer in the water and versus the thermoswitch.

my MSII unit has r4 and r7 removed, but my laptop is failing on me hardcore with it's battery and I haven't had a chance to go make sure the numbers match yet.
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Old 01-19-2010, 09:16 AM   #32
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I got the same results as you. There must be a second pull-up on the AIT circuit in the stock ECU that throws off the formula for just two resistors. Using 2625 for the CLT and 2750 for the AIT got me 35*F for both sensors this morning. My MS-I unit had 36*F CLT and 34*F AIT.

I might reinstall R4 and redo the value because I notice the CEL for the MAF was staying on in this configuration. I think the GM sensor is too far outside the OEM range and it's confusing the ECU, with the bias resistor in MS, it goes to a more happy place. I get that CEL every now and again on my MSI with R7 and R4, but had it my entire drive this morning on my MSII unit without R4 or R7. I'll test that theory out tomorrow.
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Old 01-20-2010, 08:10 PM   #33
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any luck?
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Old 01-20-2010, 09:33 PM   #34
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kept it as is
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Old 01-20-2010, 11:25 PM   #35
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that being 2625 and 2750?
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Old 01-21-2010, 10:24 AM   #36
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actually 2625 for both. the temps are damn close from what I can gander. it was 31*F out when I went out to my car, the CLT showed 33*F and the AIT 29*F. It's close enough and with MS-II I swear they display changes that are more minute and update faster on the screen (probably cause the scale is larger than 255 lines), so a small % error in the resistance scales might be showing up.

I wish I had my thermoswitch still installed so I could test the CLT sensor at 207*F when the fans trigger, but I know my stock gauge creeps to 12 o' clock at 218*F and that seemed to be spot on when I tested that over the weekend.

It's pretty close to the ballpark, and makes sense that the values match for both, those with 94-99s found theirs were both 1450ohms. So I'm just going to stick with it. CEL never came back, so i dunno what the deal with that was the first day.

I might test both sensors in water and see if they are off a bit from the published scaling, but that requires effort. I did my CLT sensor a while back and wrote it down somewhere. But I think I remember it being very close to what the service manual stats.
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