After running AE, I kinda doubt SG IIs accuracy. My SG II has been showing ECT of 186 and EOT of 198 or 199 for a delta of 12-13 at 70 MPH. Drove from Sioux City to Omaha with AE running the whole time at 70 MPH - ECT stayed at 189.20 and EOT ranged from 197.15 to 199.18. A delta of 8-10. EOT stayed around 198.2ish for most of the trip.

These are much better numbers than the SG II has been displaying. I was beginning to think my EGR/Oil coolers were going down but not anymore.

Is it just my SG II or are they all this way?

 

Check the SGII after a cold soak the ECT&EOT should be the same

if not there was a couple codes to dial them in

Interesting find though

have you checked anything eles with the AE vs SGII like Boost,ICP,IPR

Im curios to what you find

 

didn't really check anything else. i'm just always watching eot vs. ect so it stuck out like a sore thumb.

yeah at cold soak eot is always about 2.9 higher than ect. which if you do the math is the difference between my AE and SG II. maybe those codes to adjust would come in handy.

 

Ok thats good to hear I thought that we had the SGII pretty dialed in

I will see if I can find those codes
if not Im shure Amdriven2liv might have them maybe he will hit this thread

 

So, the AE gets LOWER readings... So its automatically the more accurate one??? Both have to have the cold soak done to see whats what.....

 

Ooops, guess i should read whole thread.... My Bad.....

 

I noticed that even with a new thermostat my ECT / fWT would pretty much not go over 186 with easy driving, no tow. The corresponding EOT would result in a pretty regular 10 to 15 degree difference IIRC, been a while.

Found a different xgauge code, and added 6 to the end of the MTH section. Now my ECT stays pretty much between 188 and 192 with 190 the most of the time, deltas are around 5 or less IIRC.

Basically went from panic about the coolers and HG to feeling reasonably safe, if adding 6 is correct. I now watch the ECT climb to 192 and then down, indicating the thermo is opening properly at the right temp.

In short, I too think the stock Scangauge fWT is off a bit.

 

Interesting, i did no know you could adjust the scangauge. Could the different reading be in the sensor malfunction itself?

 

rschwarzwalder i agree, my SGII is off compared to my manual gauges. I show about a 5-10 degree delta with the gauges and 15-20 with SGII.

 

So, Scangage showed ECT 186 and AE showed 189? Scangage showed EOT 198 and AE showed 198?

Those numbers are so close that they are easily within normal variation.

If you want to compare accuracy, let your engine reach a stable temperature idling in the driveway. Then quickly unplug one monitor and plug in the other. Then the numbers should be very close.

The Scangage cannot be inaccurate. The X-gauge setups could be wrong, but if they are correct then the data has to be whatever the sensors are reporting to the PCM. Remember, the Scangage is not a gauge. It is only a monitor of what other gauges are reporting. If two monitors look at the same PID, they have to report the same values.

There are some exceptions, for example where Scangage takes two PID's and has to do some math to reach a result. Like Boost for example. That is a drawback to that tool. But for ECT and EOT, those are direct readings and have to be as accurate as the sensor.

 

That is because the stock sensors and your add-on sensors are in different locations.

 

Negative, they are in the same places. Give or take a couple. inches of hose. I think the stock setting on the SGII for fWT is off for our trucks as it is just a generic parameter

 

In most cases it is only a 10 degree difference between my gauges and SGII. EOT are close to the same on both. Its the ECT that seems to be out of whack the most

 

Does anyone have the correct X-Code for the ECT as opposed to using the fWT.

 

The problem I see is that it appears this may not be so. Re-read the following post in this thread.

If this is true, then for some reason the math the Scangauge is doing to convert fWT from whatever the PCM is reporting (probably Celsius) to Fahrenheit is bad, or the Scangauge is reading the incorrect PID, or interpreting it incorrectly somehow. So is the revised xgauge code this poster used accurate? How do we know?

In my mind, this seriously deprecates the value of the Scangauge as a diagnostic tool. I would not want to have torn into a truck and done a EGR and oil cooler replacement only to find out that I did it because of bad information from a gauge.