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Discussion Starter #1
Has anyone made the IAT and/or CLT circuit so that you can data log the temps? There is a diagram on innovatives website and there is a second resistor and they don't stay what it is.

Thanks
 

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Can you attach the diagram here? Typically these sensors are resistors. Inside the ECM they will install another resistor to form a "voltage divider", two resistors tied in series. One side of the sensor is typically tied to ground. The other side is the mid point of the voltage divider. You should be able to tap into the mid point wire with your datalogger. The datalogger inputs should be very high resistance so as to not affect the voltage divider. I don't think you want to tie any other resistors in that circuit. They are probably just trying to show the ECM's voltage divider in their documentation. That would explain why it isn't labelled.
 

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Discussion Starter #3

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That diagram is for use separately from the engine sensors. The article is for a circuit to be used with their datalogger, the LM-1, not with a PCM/ECM. The key sensing element is a thermistor; and the load resistor value can be found in the spreadsheet available for download.

"Since it is feed 5v would I still need to put that circuit inline?", No, it does not apply in that case.
 

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Discussion Starter #5
That makes sense.....thanks. Guess Im just going to get another CLT and IAT sensor and feed it 5v and run that to my data logger and call it a day.
 

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You will have to insert a resistor between the 5v and the sensor if it is a standard automotive type. I can't tell you what value to use but you could probably measure the resistance from the sensor input to the 5v pin on the pcm with it unplugged.
 

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Discussion Starter #7
I still need to put a 5v resistor if I'm pulling 5v from the ECM? Is what I was told to do anyways. And that all the sensors are pulling 5v output from the ECM. So I wouldn't think that I would need the resistor unless I was getting it from a 12v source.
Going to use the temp sensor from the water pump (LT1) since I know what the values are for the table in the data logger.
 

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If you run the 5v direct to the sensor, the datalogger will only ever see 5vdc and not the real sensor voltage. Unless the datalogger has it's own 5v and resistor internal.
 

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Discussion Starter #9
I don't believe it has internal 5v resistor. Its an LM1 from Innovate motorsports.
 

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I agree with GaryDoug, you will still need a resistor to form the voltage divider. I think you are going in the right direction by getting automotive sensors. Innovate is recommending thermistors, but no method for installing them. The automotive sensors are ready to install. You can use the innovate diagram still if you want to power your sensor from 12v. the 470 ohm resistor and zener diode form a small 5v power supply. Just think of the connection of the zener diode and 470 ohm resistor as a 5v power supply. The load resistor in their diagram is the voltage divider resistor. As far as selecting a resistor for your voltage divider, find out the minimum and maximum resistance value of your sensor for the min and max temp range you expect to measure. Average those two resistances and select your voltage divider resistor as close to that value as possible. The formula for the voltage output is:

V_out=(5v)*(R_sensor)/(R_sensor+R_you_selected)

You can never get V_out to swing from 0v to 5v, but selecting the resistor as I said should get you a pretty good voltage swing. Keep us posted which way you go and we will help!
 

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One last thing, your car is OBD2 right? Do they have any cheap OBD2 data loggers that have analog inputs, so that you can record your ECM stream right along with your wideband data? I just picked up an OBD1 bluetooth adapter and it does just that. If you can find one that does that, it would get you set up much faster!
 

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Discussion Starter #12
so I need to feed the automotive sensor 12v and then regulate it down after that is what I am getting from your information. And the sensors are not getting 5v from the ECM then?
 

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I guess I got you confused. To connect a sensor to your innovate tool, you need to regulate the voltage down from 12v to 5v. You could use 5v from your ECM if you wanted. I myself don't like to mess with my ECM wiring unless it is essential. Or you can build a small 5v supply circuit like Innovate has on their website. I have to diagrams I can email you. One is the circuit from Innovate's website drawn slightly clearer. The other diagram is an alternate 5v supply. Message me your email and I'll send them to you. I hope this helps!
 

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I put the diagrams in an album on the site. Let me know if you can't find them. I think the album comes up under my profile.
 

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Discussion Starter #15
Got it....sorry I was like a dog after a treat........lol
 
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