DIACOM Errors

[Scot Sealander]

Have you noticed any DIACOM errors?  Besides O2?

I have been tuning my TGP and am having trouble getting the 
error below an integrator spread of 120 to 138 or so....  
Most of it is reasonably close, but positive transients seem 
to cause some (temporary) integrator increases, and negative 
transients can cause some integrator (temporary) lean outs.
I am assuming maybe some plenum filling, etc going on here?
The added MAF also reports bigger VE numbers during this 
time.

But back to DIACOM, the first error is in the two bar MAP 
reading.  DIACOM does not report the two bar MAP correctly.  It 
handles the 2 bar MAP as if it was a one bar MAP reading.  This 
prompted a change in the ALDL stream to put the one bar MAP value 
in there to at least get some more data points in the one bar VE maps.

But moving stuff around by DIACOM readings was not fixing things.
So while watching DIACOM, I noticed that it went into PE at 89 kPa.
Knowing that the min PE load was set to 94 kPa, this meant some 
investigation.  Putting the "MapInKpa" value in the ALDL stream for
airflow revealed that PE was indeed triggered at 94 kPa per that
reading.

At key on, engine off today, DIACOM reported 94 kPA as baro, and
94 kPA as manifold pressure.  The MapInKpa variable was reading
99 kPa.  At idle, manifold pressure was about 39 kPa, and the
MapInKpa reading was 40 kPa.

So it seems that at least the one bar MAP and baro readings may 
be off by about 5% at the high end.  The lower end seems to be
much closer.

Scot Sealander
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