Quote from: FoMoCoSHO on March 16, 2014, 05:01:59 PM
If the ECT is less than 172 degrees for 300 seconds it will throw the PO128 code.

Pg 123

http://www.motorcraftservice.com/vdirs/diagnostics/pdf/obdsm1202.pdf

Thanks for posting the url to this PDF... captured it for future use 

I read on to page 124.... where is says, "For cases where the engine is not producing sufficient heat, a timer is used to track time at idle or low load conditions (e.g. decels). If the ratio of time at idle/low load versus total engine run time exceeds 50% at the time the fault determination is made, the thermostat diagnostic does not make a fault determination for that driving cycle, i.e. "no-call"."... does that mean that if idle and cruise time are > 50% of total runtime a code won't be thrown... if so it would be an easily fulfilled criteria.

Thoughts on this?

Also of note is where it says the DTC may not be thrown if ambient temp is below 50 degrees.

Quote from: BiGMaC on March 16, 2014, 05:44:36 PM

Quote from: FoMoCoSHO on March 16, 2014, 05:01:59 PM
If the ECT is less than 172 degrees for 300 seconds it will throw the PO128 code.

Pg 123

http://www.motorcraftservice.com/vdirs/diagnostics/pdf/obdsm1202.pdf

Thanks for posting the url to this PDF... captured it for future use 

I read on to page 124.... where is says, "For cases where the engine is not producing sufficient heat, a timer is used to track time at idle or low load conditions (e.g. decels). If the ratio of time at idle/low load versus total engine run time exceeds 50% at the time the fault determination is made, the thermostat diagnostic does not make a fault determination for that driving cycle, i.e. "no-call"."... does that mean that if idle and cruise time are > 50% of total runtime a code won't be thrown... if so it would be an easily fulfilled criteria.

Thoughts on this?

Also of note is where it says the DTC may not be thrown if ambient temp is below 50 degrees.

Honestly I doubt it will ever be an issue, but the possibility is there so I just wanted to throw it out there.

Yeah that PDF has tons of info including our fuel and egr system.

TYPICAL MALFUNCTION THRESHOLD
Engine Coolant Temperature < 172 °F (for a typical 192 °F thermostat)

Since these don't have a 192* this generic figure is inaccurate. These cars won't do this unless it's well below 160*

Quote from: Livernois Motorsports on March 19, 2014, 07:56:14 PM
TYPICAL MALFUNCTION THRESHOLD
Engine Coolant Temperature < 172 °F (for a typical 192 °F thermostat)

Since these don't have a 192* this generic figure is inaccurate. These cars won't do this unless it's well below 160*

This is NOT inaccurate as I also have the 3/2013 revision SHO specific data also which states the same.

And then there's this which leads to more questions...

"Enhanced Thermostat Monitor
The enhanced thermostat monitor helps to reduce the time it takes to identify a thermostat concern. This monitor is executed once per drive
cycle during a cold start and has a run duration of 300 seconds.
During a cold start, when the thermostat should be closed, the enhanced thermostat monitor uses intake air temperature, engine speed, and
engine load to predict the engine coolant temperature. Once the predicted temperature has exceeded a target temperature for a length of
time, the actual engine coolant temperature is compared to its required threshold. This threshold is 11°C (20°F) below the thermostat
regulating temperature. If the engine coolant temperature exceeds this threshold, the thermostat is functioning correctly. If the engine coolant
temperature is too low, the thermostat may be stuck open and DTC P0128 sets."

So does this mean that this "threshold" is a preset value plugged into the ECM? Because it also refers to the "thermostat regulating temperature" specifically.

Sorry, I can't answer your questions FoMoCoSHO.  But, I can tell you this.  After running all three, stock 180, 170 and 160 (with each, their own tune).  There is really no noticeable difference in start up cycle or in continued running between them.  Of course this is just a "seat of the pants" experience. 

Edit-It does run a little cooler with the 170 and then with the 160.

Quote from: DJE624 on March 20, 2014, 10:35:09 PM
Sorry, I can't answer your questions FoMoCoSHO.  But, I can tell you this.  After running all three, stock 180, 170 and 160 (with each, their own tune).  There is really no noticeable difference in start up cycle or in continued running between them.  Of course this is just a "seat of the pants" experience.

Well like I've said before my belief is your temps will never be that low even with the 160.

What is more troubling is that some of the emission readiness items specify two different minimum temps, 160 and 170.

I'm just trying to get you guys all the pertinent info on the off chance you throw a code, or a driveability issue arises.

I now have the OBD manuals for years 2010-2013, and there is a ton of data on how all the systems work and how to troubleshoot.

Understood.  The T Stats will just open at a lower temperature.  It's really how hard you're running that will determine the actual coolant temp.  Luckily for me, we have no emissions testing in my county.