EGT Sensors and Using ECM Inputs

[Walter Sherwin]

Every ECM/PCM combo is different.  Your best bet is to search the archives,
and then ask around for individuals who are playing with your particular
"box".

Mine happened to have two spare analog channels that were not being read.
Of course,  in such an instance you will have to create a software patch to
be able to physically read these channels.  Alternately, you may be able to
simply pirate a non-critical currently active channel (ie: fuel pressure
voltage) and scale the resultant A/D values to your liking.  In this later
case you will have to cal out the original (OE) systemic effect of the port
in question, and mask out certain error code parameters in order to avoid
triggering the dreaded SES light.

If you stick to some of the "known" boxes, then there is a ton of
information/advice that can be found either at DIY or GMECM.


Walt.







>This is a great idea, and perfect for the project I am working on.  I am a
>newbie, so please excuse me if these are simplistic questions.
>
>1.  How many unused analog ports are typically available on the ECMs?  I am
>interested in doing this on GM ODBII ECMs.
>
>2.  Are there charts available for figuring out the correlation between the
>port input to the ODBII data output?
>
>Thanks for any help you can provide.
>
>Michael Adams
>
>>
>> Or, insert a signal conditioning thermocouple module (with a
>> scalable 0-5v
>> output), and feed the resultant output into an unused/unwanted analog
>> channel in the ECM, and view EGT in relation to other ECM
>> data over the
>> ALDL.
>>
>> Walt.