cold engine driveability - modify water temp resistance?

[Chad]

>FWIW, I added a Cyberdyne A/F gage to check the A/F and compare with my plug
>readings since I am running a system designed for 2.0L on a 2.3L engine.  If I
>were able to take an average of the gage display range I suspect / 
>perceive that
>the engine is slightly lean on average.

On the engines I work with, it may run lean on average, but there could be 
certain Throttle Positon/ RPM conditions that are actually too 
rich.  Richening up the entire map could worsen this, losing power.  Not a 
problem, just a consideration.

>If I shift the water temp resistance to
>give an indicated cooler temp to the ECU can I expect it to enrichen the A/F a
>bit.

On some ecu's, Yes.  Some of the ecu's out there respond more than others 
to variances in the water temp signal, so you might not get as much of a 
result as you are looking for.

>Other options that I am considering to enrichen the A/F is to replace the
>water thermostat with a lower (180 deg F) temp unit  (currently I am running a
>195 deg F unit - closest in value to the thermostat used in the GME engine.  A
>more expensive alternative would be to replace the injectors with a higher 
>flow
>rated unit.    I understand that changing the ECU state tables is a more 
>elegant
>solution but that is not a viable option based on my lack of knowledge and the
>ECU in the vehicle is the only one that I have and I would need to source a
>spare from Europe if my original were to become non-functional.
>
>patiently waiting in digest mode for any direction / suggestions

Whenever we run into an ecm that continually runs lean, we bump up the fuel 
pressure a little bit by tweaking the pressure regulator a little 
bit.  This gets more fuel through the injector while it is open.  There are 
other considerations here, but it works well with a continuously lean engine.

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