Air Temp Sensor
10-24-2003, 04:28 PM
#1
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Join Date: Apr 2003
Location: Schofield Barracks, HI
Posts: 2,259
yo im switching out the stock air temp sensor for the haltech one....where is it on the car ? i dont wanna look up and download a fsm since im at my friends house
thanks in the advanced answering of my questions
mike
?
thanks in the advanced answering of my questions
mike
10-24-2003, 05:02 PM
#7
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Join Date: Mar 2003
Location: ATX
Posts: 1,535
You can't use the stock sensor with the Haltech. There are two different size sensors that ship with the Haltechs, 3/8NPT and 14mmx1.50, make sure you tap the proper sized hole. I taped a 3/8NPT hole assuming that was the sensor I had, then came to realize I had the 14mm sensor. Oops! Just installed my new 3/8NPT sensor today....
10-24-2003, 05:50 PM
#9
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Join Date: Apr 2002
Location: IL
Posts: 2,930
technically speaking, you CAN use the stock sensors, it just means the temperature value will be off in the software. This does not matter when it comes to tuning the car and making it run well, because you will be tuning it with that sensor in the car. It does matter, however, if you plan on actually using those #'s as real temperatures for your own information.
Why is this the case? It's quite simple actually, the temp sensors don't generally have a linear relationship between resistance and temperature, and the relationship varies from one type of sensor to another. So the software has a "look up table" which has the real temperatures stored in it, at the location indexed by the resistance (or voltage from the ecu perspective) which occurs at that temperature. What this means is you can use whatever sensor you want as long as it's a thermistor. What are the negatives? The look up table in the software is calibrated for the GM/haltech sensors, so it will only show correct temperature values when using those sensors. Using the stock sensors will make it off FOR YOUR EYES, the ECU does not care, you are in control.
In the software I've been developing to work with the E6K you can define the look up table values so you can calibrate whatever sensor you want, but this is just so the gauges display the correct temperatures and crap, it doesnt affect the functionality of the ECU.
The other major negative to using different sensors from the rest of the world, is you cannot take maps from the rest of the world and expect them to work *without adjustments* even if your setup is otherwise identical. Since the sensors output translates differently it will be referencing a different part of the fuel / correction maps than it would be with the correct sensors under the same conditions. If you plan on using someone elses map you better make sure you are using the same sensors. It's probably not even safe to assume the rest of the world uses the GM/haltech sensors, like in my case, I'm using the FC coolant sensor for now. But I don't care, I use my own software for the display of engine data and I have control over the coolant correction map.
If you look into the megasquirt ECU web site, under the software and junk they have code for generating these lookup tables for whatever sensors you want to use, but it's megasquirt-specific. Still interesting though, they have an example lookup table for use with the GM sensors to save you the trouble of making one. To make the lookup table you watch the voltage and heat the thing up in water or whatever noting voltage:temp at a number of points... then it interpolates between them for you to fill up all 256 entries in the table.
sorry bout the long post, this subject is fresh on my mind, and people often say you cannot use stock sensors with the haltech which technically is not true.
Why is this the case? It's quite simple actually, the temp sensors don't generally have a linear relationship between resistance and temperature, and the relationship varies from one type of sensor to another. So the software has a "look up table" which has the real temperatures stored in it, at the location indexed by the resistance (or voltage from the ecu perspective) which occurs at that temperature. What this means is you can use whatever sensor you want as long as it's a thermistor. What are the negatives? The look up table in the software is calibrated for the GM/haltech sensors, so it will only show correct temperature values when using those sensors. Using the stock sensors will make it off FOR YOUR EYES, the ECU does not care, you are in control.
In the software I've been developing to work with the E6K you can define the look up table values so you can calibrate whatever sensor you want, but this is just so the gauges display the correct temperatures and crap, it doesnt affect the functionality of the ECU.
The other major negative to using different sensors from the rest of the world, is you cannot take maps from the rest of the world and expect them to work *without adjustments* even if your setup is otherwise identical. Since the sensors output translates differently it will be referencing a different part of the fuel / correction maps than it would be with the correct sensors under the same conditions. If you plan on using someone elses map you better make sure you are using the same sensors. It's probably not even safe to assume the rest of the world uses the GM/haltech sensors, like in my case, I'm using the FC coolant sensor for now. But I don't care, I use my own software for the display of engine data and I have control over the coolant correction map.
If you look into the megasquirt ECU web site, under the software and junk they have code for generating these lookup tables for whatever sensors you want to use, but it's megasquirt-specific. Still interesting though, they have an example lookup table for use with the GM sensors to save you the trouble of making one. To make the lookup table you watch the voltage and heat the thing up in water or whatever noting voltage:temp at a number of points... then it interpolates between them for you to fill up all 256 entries in the table.
sorry bout the long post, this subject is fresh on my mind, and people often say you cannot use stock sensors with the haltech which technically is not true.
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