I have already been very careful to avoid shared maps, which is why I made a new map for the MAP calibration. The only shared thing is the RPM axis for the RPM VE table - if you change this you also change the RPM axes on many other tables. However, there should be no need to change it since RPM is a minor effect and we have 500-8000 RPM.

 

As for the Baro sensor....

Can you just clamp it to a certain value and be done with it? That or remove any sub routines that affect changing fueling?

 

How does fluctuation in baro affect the tune.

 

There are many routines that use it, easier to clamp it to one value I think.

The only reason to have it with SD is the effect on VE that you have at altitude. It is not needed for basic airflow estimation like it is with a volume airflow sensor.

When the barometric pressure drops, the turbine speed will need to be higher to maintain the same MAP. This will increase exhaust manifold pressure and reduce VE. Without barometric pressure compensation you will get a richening as the baro drops. I think this effect will be minor in the UK with its relatively flat elevation. It may be an issue in the US. Unfortunately I have no experience of altitude tuning, but you could keep a sensor and still compensate for it. Whether the stock baro adjustments will be too much I don't know, someone will need to test.

 

My main concern with IAT and baro is that I think they play a role in the ISCV step determination. I need to go back and double-check.

 

Couldn't we just stay in open loop and do away with the ISCV? We could use our base timing and fuel maps to tune for idle. Prior to advanced throttle bodys...this is how it was done. I may have it backward....open loop vs closed loop always confuses me.

 

ISCV idle is nicer though if it can be made to work. A very heatsoaked car with a hot MAT may try for a different set point perhaps.

If we keep IAT, it would be more correct to compensate the load calculations with MAT though.

For simplicity I'd be tempted to just substitute for my own car and then junk the whole MAF housing/sensor and put a pretty pink lampshade onto the turbo inlet pipe with some heat shielding.

 

What I can say is that Clearing of DTC clears MUT_40-MUT_49 values,
these values are OR-ed when creating PXXX DTC value,
moreover MUT_36 and MUT_37 are zero-ed, they seem to be DTC counters.
When clearing also MUT_71 (sensor errors) gets cleared, and MUT_8D is zeroed.

its 0xFA or 0xFC, they always clear DTC, but also some other different data (Freezed frames vs. Pending DTC?).

Moreover it seems that 0xF8 gives engine info summary.
Load + RPM + Battery + Barometer + Speed + Coolant temperature and some others that I do not have yet disassembled.

 

ISCV is required for both closed loop and open loop idle, so its important to make sure it works well for a daily driver.

jcsbanks, I definitely agree that MAT needs to be used for the SD stuff. Just want to make sure that things that depend on IAT (and baro) continue to work properly.

 

So where would we get the MAT values?

 

You would have to add something like a GM IAT sensor in your intake manifold or post turbo like in your UICP.

 

If that is the case, then why not add a GM MAP sensor too?

 

I have both of these installed already not an easy job fitting the MAT sensor
thats why I offered to test it out,

 

because you can get a stock replacement 3 bar map sensor that doesn't require any sort of calibration.

 

AHHHH it is all starting to come together....."I love it when a plan comes together" A-Team ! !