LT1 Based Engine Tech 1993-1997 LT1/LT4 Engine Related

Ok to extend IAT wires?

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Old Mar 12, 2009 | 09:50 AM
  #1  
IFLYAZ's Avatar
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Ok to extend IAT wires?

I want to move the IAT over into the Moroso CAI ducting, but wire is too short to do so. I've got some 18 gauge wire handy but I wanted to check with you guys to see if it will screw up the resistance on the sensor to lengthen the stock wiring. (95 Z28)

Thanks!
Old Mar 12, 2009 | 10:15 AM
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'94 Bad A Z28's Avatar
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You can just get a 4.5kOhm resister for the IAT sensor and it tells the PCM thatthe air coming in is 40*F.


Do a search on here for "resistor mod" or "IAT resistor" to be sure of what size resistor, but I am pretty sure it is 4.5kOhm.
Old Mar 12, 2009 | 03:20 PM
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Originally Posted by '94 Bad A Z28
You can just get a 4.5kOhm resister for the IAT sensor and it tells the PCM thatthe air coming in is 40*F.
Why...? So the computer enriches the air/fuel mixture beyond the stock settings (which many people believe is already too rich)? If you want more power lean it out a bit if anything.
Or is it so if you're MAF has a failure, speed density mode will no longer work as it won't know the temperature if the intake air? or is it just to mess up quick-throttle fueling transitions?
Old Mar 12, 2009 | 04:25 PM
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Originally Posted by MikeGyver
Why...? So the computer enriches the air/fuel mixture beyond the stock settings (which many people believe is already too rich)? If you want more power lean it out a bit if anything.
Or is it so if you're MAF has a failure, speed density mode will no longer work as it won't know the temperature if the intake air? or is it just to mess up quick-throttle fueling transitions?
So, have you found the programming tables for it in TC or LT1 Edit?
Old Mar 12, 2009 | 05:00 PM
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Originally Posted by '94 Bad A Z28
You can just get a 4.5kOhm resister for the IAT sensor and it tells the PCM thatthe air coming in is 40*F.


Do a search on here for "resistor mod" or "IAT resistor" to be sure of what size resistor, but I am pretty sure it is 4.5kOhm.

Such a bad thing to do.
Old Mar 12, 2009 | 07:17 PM
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Wow, this thread kinda got side tracked huh?

I did a search about extending the IAT [I]WIRES[I] but came up empty. In other words, splice in a couple lengths of wire to make the sensor reach farther over to the driver's side front where the Moroso intake ducting is. I want to keep the sensor active (computer using it).

Without arguing over whether or not it should be "resistored" this time, can someone tell me if this is ok to do?

Thanks
Old Mar 12, 2009 | 07:28 PM
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I did it years ago and haven't had any problems with it. I'm sure it's not the best way as I have seen plug in extension harnesses, but whatever works.
Old Mar 12, 2009 | 07:45 PM
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Lol sorry, we didn't mean to hi-jack your thread.

Yes you can extend the wires as long as you want. It will not alter the total resistance or anything. I would definitely solder and heat shrink them though.
Old Mar 12, 2009 | 10:47 PM
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Originally Posted by IFLYAZ
Wow, this thread kinda got side tracked huh?

I did a search about extending the IAT [I]WIRES[I] but came up empty. In other words, splice in a couple lengths of wire to make the sensor reach farther over to the driver's side front where the Moroso intake ducting is. I want to keep the sensor active (computer using it).

Without arguing over whether or not it should be "resistored" this time, can someone tell me if this is ok to do?

Thanks
As long as you use the same gauge or thicker and a nice job of connecting them together, you are fine.
Not sure why you would think the sensor is not "active" in the stock location.
Old Mar 12, 2009 | 10:51 PM
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Adding length to the wires will always add resistance, but as long as you use a wire size larger than the wires you are extending, you will not add enough resistance to the circuit to make a significant difference in the IAT readings. The IAT sensor has a resistance ranging from 9,420 ohms at 32*F to 667 ohms at 140*F.
Old Mar 12, 2009 | 11:50 PM
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Originally Posted by Injuneer
Adding length to the wires will always add resistance, but as long as you use a wire size larger than the wires you are extending, you will not add enough resistance to the circuit to make a significant difference in the IAT readings. The IAT sensor has a resistance ranging from 9,420 ohms at 32*F to 667 ohms at 140*F.
lol 18awg copper wire is in the vicinity of 7 miliohms per foot.
As long as you dont add 10 or 20 THOUSAND feet of wire to your IAT, you'll be just fine
Old Mar 13, 2009 | 12:35 AM
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Originally Posted by Kevin Blown 95 TA
So, have you found the programming tables for it in TC or LT1 Edit?
tables for what? IAT, AFR...?
Old Mar 13, 2009 | 12:41 AM
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Originally Posted by shoebox
Not sure why you would think the sensor is not "active" in the stock location.
I was reading about the heat soak problem and wanted to move it to an area that gets more realistic air temp rather than skewed by the heated intake elbow. Here in Florida when it gets really hot outside in the summer, my car seems to run rougher than it does in the winter. I thought moving it to a cooler location upstream might help.

The "active" reference was to let people know I want the computer to read it as it was meant to be read in the stock location or new location, not use a resistor to fool the computer.

By the way, shoebox, thank you for your website! It has helped me out with many different projects over the years!

Thanks also to everyone else for the suggestions.
Old Mar 13, 2009 | 01:33 AM
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have you done the throttle body heater delete mod?
Old Mar 13, 2009 | 02:10 AM
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A more realistic temperature would be obtained closer to the engine because air will be cooler at the begining of the intake track then by the time it gets into the engine.



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