IAT Wiring Question

[rrrocketman]

For an SS, there are 5 wires (I think) in the harness that combines both the MAF sensor and the IAT. They are:

"Low Reference"
"Ground"
"Intake Air Temp Sensor Signal"
"Ignition Voltage"
"MAF Sensor Signal"

but not particularly in that order, as this order is for a V6 I believe.

I want to do the old IAT trick for a nitrous setup where you fake out the temperature to enable a column in the IAT table that adds injector duty cycle for more fuel. However, I need to first verify which wire to splice into and second what the complete circuit looks like. I'm assuming that the resistor in the IAT sensor creates a voltage divider with a fixed resistance in the ECU. Therefore, depending on how the circuit looks, I need to know whether to splice into the IAT wire or the low reference wire (assuming the IAT works with that wire as opposed to ground).

1) Which ground wire is used with the IAT. Is it "ground" or "low reference"?
2) What are the colours of the wires in question
3) Where is the voltage divider? Is the middle of the divider between the ECU and the IAT (splice into the IAT wire to sample the voltage) or is it between the IAT and low reference (splice into the low reference)?

If someone could draw a simple block diagram showing the schematic showing where the resistors are and where the voltage is sampled, that would be great. Much appreciated.

[rrrocketman]

I'd be satisfied if someone could answer even question 2... if nobody knows the rest.

[Retro69]

You could always pop one of the contacts out of the connector and see what kind of code the ECU throws.


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[rrrocketman]

I suppose that's 1 way to do it... I could also brush my teeth with steel wool lol.

[hammdo]

Breakout harness would get you the maf and iat seperated...

http://www.camaro5.com/forums/showpo...postcount=1785

Just in case you may want an alternative...

Light Blue and Tan I believe are the iat wires...

-Don

[rrrocketman]

Originally Posted by hammdo

Breakout harness would get you the maf and iat seperated...

http://www.camaro5.com/forums/showpo...postcount=1785

Just in case you may want an alternative...

Light Blue and Tan I believe are the iat wires...

-Don

Awesome that's very helpful.

What I want to do is actually inject voltage right onto the IAT wire rather than use a relay/resistor setup. I have a microcontroller with which to do this and assuming I can isolate the source so it is not seen as a load, I should be able to apply any voltage I want to simulate any temperature, or simply disable the output and let the IAT sensor drive that. If I splice onto the IAT wire (light blue?) and apply the voltage on that node, do you think the ECU will detect it properly?

[hammdo]

Very likely but I’ve not tried it. You could test to see what the ECM detects...

-Don