MS43 E-Thermostat Issues

[KI4UJO]

I recently dropped a 3.0 M54 into my e30 (I previously had an M50) and am very happy with it. However, I am experiencing a bit of an issue with the e-thermostat. Currently, the thermostat seems to be opening around 160deg F. It is worth noting that I am not running a radiator outlet temperature sensor. While i have done a fair amount of research, I am yet to turn up a set of parameters required for the e-thermostat to operate normally vs going into a fail safe state.

Any ideas? I need to tailpipe test the car and HC is slightly high due to the low temperature.

[TobyB]

Just unplug it.

It's a standard 96c thermostat with an 'oh shit' heater built into it
to open it when 'circumstances dictate'.
Mine has been inop in the E46 for months.

And yes, MS43 gets pissy if coolant temperature isn't pretty close to normal.
The unplugged heater will throw an OBD code, but not cause any other problems,
The missing temp sensor will cause others, but quite likely nothing else that bugs emissions.

Your air conditioning won't work- if MS43 is enabling it...

t
unheated

[KI4UJO]

I ended up finding a parameter which affected thermostat temperature if an external low temperature condition was reported. With that changed, it now opens at the correct temperature and passed a tailpipe test.

However - I am not a fan of the plastic thermostat, specifically the quick connect ends. I'm definitely interested in getting rid of it. If possible, I would like to use a housing from a 1997 528i in order to have an aluminum location for the temperature sensor vs being located in the plastic hose end.

[Verty30]

Hey, I am having a similar problem with my swap. Just curious what you mean by parameter and how you were able to fix it? Thanks!