MPScan charge temp sensor reading.

[DoubleD]

Paging Wowzer
I have been logging with MPScan most of the summer. I recently added the charge temp sensor to my gauges. I assume the charge temp sensor is located in the Intake Manifold (TIII) The guage currently reads out a voltage. What would it take to either covert this voltage to a temperature or add another gauge that simple showed the actual temperature. As for example, I know the Coolant sensor outputs a voltage, but I have a nice gauge to read on farenheit. I would also like this for the charge temp sensor so I know the temp of the air in the intake manifold.

[ShelGame]

Depends on the year. If its SBEC, you can use the same scale as the coolant temp sensor. The SMEC can't though.

[DoubleD]

This is on a 92 SBECII TIII, here is a table I found from an older post on the other forum:

IAT readings

0 F=4.70V
40 F=4.11V
60 F=3.67V
80 F=3.08V
100F=2.51V
120F=1.97V
140F=1.52V
180F=0.86V
220F=0.48V
240F=0.35V

I was also digging around MPScan and under the xref setting, I see that there is a Charge Temp CHRG, but there is no location for either of the TIII's. Is there no RAM location for the sensor on these ecu's.

The numbers above seem to coincide with the voltage readout given by MPScan. Today the intake temps were 75-80 according to the above table extrapolating 3.2-3.4V.

[x.Gen]

http://www.turbo-mopar.com/forums/showthread.php?32186-Anyone-w-scan-tool-and-Charge-Temp-Sensor-Enabled

thank AJ for the effort, have to go back a bit for this info. point of all the data being stock sensors are pretty inaccurate, should be replaced with better. something to think about when you are tuning.

Temperature in degrees F
Volts---1st-----2nd------3rd-----4th-----Average
3.2-----NR-----NR-------75------NR---------75
3.1-----NR-----NR-------94------NR---------94
3.0-----80-----78-------106-----NR---------88
2.9-----103----100-----111-----84---------99.5
2.8-----112----112-----116-----104--------111
2.7-----117----117-----120-----111--------116.25
2.6-----119----120-----122-----114--------118.75
2.5-----124----127-----134-----116--------125.25
2.4-----139----137-----143-----128--------136.75
2.3-----145----140-----148-----135--------142
2.2-----150----144-----150-----142--------146.5
2.1-----151----150-----153-----149--------150.75
2.0-----160----180-----172-----158--------167.5
1.9-----197----195-----181-----164--------184.25
1.8-----205----205-----187-----166--------190.75
1.7-----224----212-----191-----174--------200.25
1.6-----231----218-----207-----177--------208.25
1.5-----238----222-----220-----182--------215.5
1.4-----242----231-----238-----184--------223.75
1.3-----257----245-----239-----197--------234.5
1.2-----265----256-----247-----199--------241.75
1.1-----265-----NR------NR------NR--------265
1.0-----265-----NR------NR------NR--------265

[DOHCRT]

Having said all of that, how much of an effect on tuning or driveability does the sensor actually have? I think the one in my R/T is bad, because my OTC displays -50F all the time. In theory it should be running richer than normal? I get crappy gas mileage, but I can't see this sensor affecting the actual tune that much?

Thoughts?

[x.Gen]

that reading doesn't make sense. Rob can likely speak in more specific terms than I can, but it shouldn't affect your mileage. actual change in a/f is barely noticeable. with the stock sensors, (my experience and) from most of the posts on the subject it seems once the manifold warms up it basically heat soaks the sensor and you get the equivalent reading that you'd get from coolant temp from that point forward. so the fact that the sensor indicates almost full cold at anything other than cold start indicates the sensor is shot, or something is way off elsewhere. first thing to do is put the DMM to that sensor and get an idea of what direction to go in. if the sensor is bad, search caged sensor here and find a replacement worth bothering with.

http://minimopar.net/ecu/charge_temp_se.html

[DoubleD]

Rob,
Any chance that you could get MPScan to show a temperature reading and not the voltage value that shows up currently? Would be great to see how much the intake temperatures drop after switching to E85.

[OmniLuvr]

I think the temps would prob only "drop" after where the e85 is being injected, but you never know?

[DoubleD]

I agree with that, I would really like to see my intake temps, should also let me see how efficient my intercooler is too.

[ShelGame]

The problem is, it's not a linear relationship. So, any scale we could put on it in MP Scan would not be accurate.

This is why Chrysler switches the dropping resistor on/off for the stock coolant temp sensor (and for the IAT in the SBEC). They try to make it more linear.