[dieseldogtom]

O.K. Larry..... And I am not starting an argument here but I feel like the information you are providing might be wrong or maybe I should say (can you explain this). EVEN though some parts DO seem to hold up. There IS a reading in one of the factory set (ScanGauge2) positions that does indeed read as you say, (a -40 deg.), BUT how do you explain the readings I get when I put in the codes provided by 505live into one of the (x gauge) positions? They MUST be coolant temperature readings because they are completely independent numbers. They rise and fall just as you would expect to see the coolant numbers do. They vary from the oil temp. figure again, very much as you would expect coolant temps. to do. So just what is the ScanGauge2 picking up here? While it does not work perfectly as described above. Once it gets over the 254 degree (hump) it goes right to 127 degree reading at just about the amount of engine running time you would think it takes to get to 127 degrees, and continues to rise just
as if it had a physical probe sticking in the system somewhere. It's NOT oil, Transmission or air temp. So just what the heck is this gauge picking up from the OBD port, if as you say, the coolant temp. goes straight to the dash gauge and there is NO active information being sent through the OBD port or to the PCM? Oh, The 175 degree which IS lower than the factory 193 or 195 is probably (IMHO) because of one or two reasons. First, I hardly ever go far enough or hard enough to get up to full temp. and Second , and I think more likely, I probably have a thermostat that needs to be replaced because (and I am just guessing here because I am not a mechanic or engineer) The spring has probably weakened and is causing the stat. to open earlier. OR I might have it backwards depending on how these things are designed. The spring might get stiffer from (work hardening)(multiple times being heated & cooled) and causing the same problem......getting a stat. that opens at the wrong temperature. Hence my 175 or so high readings. Probably why I read that the stat (even the 203) should be changed every year or so. (Not that anyone does that) BUT it IS written up in the technical manuals AND on the dieselite.com site.
NOW, I very well might be completely WRONG (it will not be the first time) but I would like to hear from some other (EXPERTS) on this question to get a more (rounded) opinion as to about what this gauge is picking up using 505Live's provided codes.
Sure looks like coolant temps. to me. Thanks for your time DDT

 

[RT]

Its not picking up anything. It is a calculated value by the PCM. Its not real. The coolant temperature sensor isn't wired into the PCM on any 7.3 except the manual shift models. That's straight from the Ford service manual.

 

[bork]

Then what is it picking up? What if a person would unplug the coolant sensor? what happens?

 

[RT]

It is picking up the calculated value from the PCM. None if these values are straight sensor values- they all are the PCMs data. Try unplugging the sensor and report back.


Sent from AutoGuide.com App

 

[dieseldogtom]

O.K. Lets try this one more time. Again, Not trying to "get into it" with anyone (RT or Larry) O.K. First lets look at a few things. Notice the length of my post? That's how you communicate full and comprehensive thoughts & ideas. RT says "It's not picking up anything". What is "It's"? If "It's the ScanGauge, it sure as hell is picking up something! Those digital numbers that are being displayed on the readout and that are changing at what seems to be a pretty accurate depiction of what the coolant temps. would be are not the -40 degree "dummy" value as you described earlier.
NOW , Are you (trying) to say that the PCM DOES get values for EOT, TFT, Intake air temp... and then based on those actual sensor picked up & transmitted to the PCM figures, (calculates) out or (estimates) what the ECT might be?
OR, are you just saying that there is simply NO data from a sensor that is connected to the coolant system (somewhere) , that transmits ANY data back to the PCM about what the temp. of the coolant is?
That the only connection from a coolant sensor is straight to the gauge on the dash?
This leaves me asking again, Where , what or how is the ScanGauge (which is connected to the OBD 2 port), And when programmed with the codes that 505Live has provided, pumping out those figures that it does?
Now I know this might be a little bit long of a post again, but the 2 and 3 line answers don't really do much but to cause long threads with LOTS of posts. Especially when they include acronyms like AFAIK. Maybe someone can write it up in another way if it is TRUE what RT & Larry are saying so we ALL might be able to understand how the SG2 is displaying those numbers, But they are really just "made up " or calculated out by the PCM & then transmitted through a OBD 2 port pin. Even though the SG 2 DOES INDEED have one of it's pre programmed parameters showing up as -40 degrees. BUT when programmed with 505Live's set of codes shows a changing/rising set of numbers that seem to directly relate to ECT. Thanks DDT

 

[RT]

Notice the length of my post? That's how you communicate full and comprehensive thoughts & ideas.

My apologies for the length of my answers. For this one and only time, I will try to lengthen my response. There are several reasons for my short answers. First and foremost, I was trained in medicine, the sciences, and engineering. Brevity is ingrained in our communication. Whereas a political sciences major or journalism major may be trained to turn what could be a two word answer into a 5 minute speech, we are not. You are taught to communicate in quality, not quantity. Secondly, I am male. Studies indicate that men use 3-5 thousand words a day, whereas women use 30-40 thousand a day, with gusts up to a hundred. See, that's funny because it sounds like a weather forecast. The last, and least excusable reason is that I was typing on my iPhone. For someone who learned to type on a manual typewriter, that's not fun. I deliberately try to abbreviate answers because I hate typing on a screen that can be obscured by a business card.

To answer some of your questions. We were talking about the ScanGauge, so when I use the term "it", I am referring to the ScanGauge. Its a mechanism in English to shorten sentences. Sorry if that was confusing.

You say, "it sure is hell is picking up something." Well, that's not necessarily true. Cause and effect is not always direct. In an effort to lengthen my post, I'll give you a long winded example. When I was a boy, we lived in Libya. My father was a petroleum engineer and Khadafi hadn't gone crazy yet. Everyone there had step up transformers that monitored a/c line voltage and gave you the ability to adjust output as incoming voltage fluctuated wildly throughout the day. Every time you walked by the refrigerator, you would check the voltage and make an adjustment if needed. Over time, I noticed the voltage in the AM was about 80 volts and by noon it was up to 120 volts. Then in the afternoon it would go back down to 80 volts. Coincidently, that corresponded pretty close to ambient temperature. Now a scientist such as yourself could come to the conclusion that that gauge was somehow monitoring temperature, given it was very closely related to temps throughout the day. You would be wrong, but could argue the point nonetheless.

Yes, the Scangauge is picking up something. Yes, at some points it seems to mimic oil temperature. When I first got my Scangauge, someone else was trying to do this very thing, so I put the 6.0 ECT parameters in my Scangauge and tried it as well. If memory serves, I started out below freezing and slowly crept up to around 400°, then it seemed to reset down to around 150° and came back up to around 180°. Seemingly, very close to what you would expect the coolant temps to be. The scientist that I am, I disconnected my coolant sensor and ran the truck again. Exactly the same behavior. I know for a fact there are no other coolant sensors on the 7.3, so logic tells me its getting the information, if it is real at all, from somewhere else.

Now - where is it (the temperature reading) coming from? While I haven't attempted to decompile the PCM's operating system, I can theorize that it is either 1. a calculated value by the PCM using other parameters (such as EOT) as a baseline, or 2. Some totally random sampling that mimics what one would expect EOT to look like closely enough to fool you into thinking it might be related. So, what to do (about the temperature reading.) Given we know it isn't really coolant temperature (disconnecting the sensor didn't make a difference), then the short answer is - who cares? The ScanGauge is capable of EOT readings. That is closely correlated to ECT in the 7.3 given we don't have the nightmare engine oil cooler issues that the 6.0 has. I did install a mechanical coolant temperature gauge in my truck. I can tell you that it never varies from the EOT temps by more than 1-2°. I didn't put the gauge in because I really wanted to know the temps, but because I had a three gauge pod for fuel pressure and oil pressure and it looked funny without a third gauge in it and ECT was cheap.

I will give you one other observation to try to lengthen this a little more. When I was programming my ScanGauge, I made a slight boo-boo (scientific term there) when programming EBP. I left out a zero in a long string of zeros. Now, Mr. ScanGauge gave me a reading for EBP. It didn't quite make since given the sensor is an PSI-absolute sensor, not a
PSI-ground sensor. My reading should have been around 14.4 psi with the KOEO, but it wasn't. It was zero. Still, it went up a few points when I did WOT test runs, but it just wasn't right. One could ask, "what sensor was this thing picking up?" or "where is this data coming from?" The correct answer would be, "no where." It is artificial data. It doesn't mean anything. Which is also what you are seeing when you program the ScanGauge to monitor a PID that doesn't exist on the system you are measuring - no matter how closely it resembles what you expected to see.

I hope I answered your questions satisfactorily. I'm afraid I won't be able to provide any more length to this answer as my hand is beginning to cramp...:read:

 

[dieseldogtom]

Nice job RT! Here, Here, Way to go! Nice detailed answer that covered it all and gave much better explanation of how/why those numbers could be there and be so close to what one would think is a proper ECT reading. I even enjoyed the sarcasm & womanly insults!! But you did make a mistake a couple of times I believe when you meant to be talking about the ECT you wrote EOT.
By the way, sorry, I have no idea you were using a small key pad to type on previously.
Now let me say just one thing as well. In my short and uninformed little life I have seen or more appropriately heard to many times when someone that doesn't know their ass from a hole in the ground, throw out quick little (non detailed) answers just to (act) like they have a clue about whats being talked about. (NOT saying you).
So that's why I look for longer, detailed & specific answers to questions like this one , to make sure I here from MULTIPLE sources before I just believe the first thing I am told in some short little reply as being the way it is.
Today, I had a question/issue with what seemed to be cracks on a small 2 stroke engine cylinder head. I talked to 3 different people about it before I came to a reasonable conclusion that they were just casting marks. All three of these people were wery friendly and polite and had no problem talking about that issue and we even went off subject & talked about other things. Now I realize there is a BIG difference between talking on the phone & typing. (Must be the scientist in me), And I see this reply is getting a little long as well (must be the woman in me) so I will end it here. Thanks for the time to give all those details & information, though I do think you could have left out some of the parts that were just to make a point of making it a long reply and the little back handed insults. I was not trying to personally attack you when I mentioned what I did about the short reply s I was getting to the question. But I really do appreciate the parts of your answer that were on point. Thanks DDT

 

[bork]

Thanks guys! Time to rest the ol eyeballs now.:freak5: