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Post Info TOPIC: Coolant temperature and air temperature programming investigation thread


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Coolant temperature and air temperature programming investigation thread


As noted elsewhere, it has come to my attention the need to get a handle on the coolant temperature  and air temperature compensations. This thread can serve to discuss all findings related to coolant and air temperature sensors. Wile it is in teh GEN2 section, GEN1 information is likely valuable as well.



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GEN1 information from Petri in 2008 is located here:
http://ecuhacking.activeboard.com/t15857298/coolant-temperature-to-injector-pulsewidth-path/

The coolant sensor subroutine AD_Water_Temperature_sub_8D48 converts the coolant information from FFFF81D2 into a variables FFFF8368,8369. The FFFF8368 variable is then at certain intervals copied to FFFF83D4.

Then in the Coolant_enrichment_FFFF84D2_sub_DAF8 subroutine the coolant sensor value is calibrated by either to be used with <23% or over 23% TPS settings. This indicates that the coolant sensor output is synchronized either for IAP or TPS map ? The final result is stored into variable FFFF84D2.

As a last stage to convert the coolant sensor information into a figure that calculates the additional fuel for engine the subroutine Calculate_various_compensations_FFFF84B0_FFFF84AE_sub_F718 adds coolant compensation into variables FFFF84B0 FFFF84AE for calculating injector pulsewidht. The calculation is fairly complex and currently unresolved and involves 10 other variables.

There is additionally a coolant/RPM ignition advance 3D tuning map, but that is obviously not related to fuel injector pulsewidth.

Based on earlier testing the coolant temperature affects the fuel injector pulsewidht only a minimal amount - so its usefullnes for finetuning may not prove to be practical. The fuel flow is way more dependent on intake air pressure and ambient pressure. Hence some of the reported cold start problems with Turbo engines may be better fixed with tuning the IAP maps.




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John a quick look over the k8 bin in raider , and i think the tables to check will be either the x36 or x27 , they look like temp compensation type of range , but this is only a guess
just a quick cross reference on what the gen 1 compensation tables look like

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Thanks Greg. Can you shoot me the romraider definition for K8 via email? I don't have it.

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Looks like the coolant warmup enrichment threshold is located at &H72531


Starting at line 1252 of K8Advsettings.vb

Private Sub C_warmup_CheckedChanged(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles C_warmup.CheckedChanged
If Not loading Then
If C_warmup.Checked = True Then
C_warmup.Text = "95C thermostat"
WriteFlashByte(&H72531, &HC8)
Else
C_warmup.Text = "60C thermostat"
WriteFlashByte(&H72531, &H8F)
End If
End If

End Sub



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