How important is the IAT sensor?

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Sep 12, 2007 | 10:51 PM

Projectcam94

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Joined: Jun 2005

Posts: 326

From: South Texas

How important is the IAT sensor?

Im getting a 23 and 66 code when i hook up my ALDL cable..

23: Intake Air Temperature (IAT) sensor circuit (signal voltage high, low temperature indicated)

66: A/C refrigerant pressure sensor circuit (open or shorted)

Anyone think the IAT sensor can be causing my car to bog down ? I havent solved this issue ... This only happens when the car is hot(normal temp).

Thanks

Sep 12, 2007 | 11:06 PM

seawolf06

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Posts: 3,034

From: Raleigh, NC

It's pretty important. I think it can control timing to some extent.

Sep 13, 2007 | 01:31 AM

mmmchickenboy

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From: South Bend or Ft. Wayne, IN

See post #5.

Last edited by mmmchickenboy; Sep 13, 2007 at 10:50 AM.

Sep 13, 2007 | 07:51 AM

Projectcam94

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From: South Texas

nice ill buy one today thnks for the responses

Sep 13, 2007 | 08:14 AM

Injuneer

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From: Hell was full so they sent me to NJ

Quote:

Originally Posted by mmmchickenboy

Very. The PCM calculates fuel needs based on that sensor as well as the MAFS, MAPS, RPM, TPS, etc. As the temperature of the air changes, so does its density. So, if it's less dense (warmer), the engine requires less fuel to attain 14.7afr. If the sensor is malfunctioning (and the PCM recognizes this, i.e. sets a code) then it will probably over fuel the motor to be safe, which MIGHT account for your bogging.

Not in an MAF car. The IAT is used in speed-density to calculate the density of the air. But in an MAF car, the MAF sensor measures the air mass flow directly. In the MAF cars, all that we can find is an apparent relationship to 3-degrees of timing that appears to be added to the timing tables when the IAT sensor is not at a very high temperature.

It should not be causing the car to bog.

Sep 13, 2007 | 08:24 AM

Projectcam94

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From: South Texas

Any way to test it? i looked at shbox website and couldnt find a way .. The thing is a mechanic told me he had replaced it.. But i dont believe him... I think he just erased the code .. Then it just came back...

Should i check the harness that connects to it with a vvolt meter?

Sep 13, 2007 | 08:27 AM

Injuneer

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From: Hell was full so they sent me to NJ

Shoebox has an instruction on how to test temperature sensors. You measure the resistance across the pins of the sensor, and compare the ohms to the table of temperatures vs. resistance. Also, with key on, disconnect the harness connector and make sure you are getting +5V across the pins of the connector.

http://shbox.com/1/4th_gen_tech2.html#ect

Sep 13, 2007 | 08:27 AM

Projectcam94

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Joined: Jun 2005

Posts: 326

From: South Texas

ok thanks

I checked and i am getting 5v on the pins of the connector.. Replaced the IAT with a new one and it still bogs down and idle goes up and down..

So far things ive done
New IAC
New IAT
Oil Change
Fuel Filter change
Icm Cool Mod
Sea foamed the TB, intake, Fuel injectors, vacuum line

PCM was only throwing the 23 and 66 code.. 23 is gone since i replaced the IAT sensor.

How can i detect if its the opti with the ALDL cable that i got and the program freescan ? Spark Advance goes up and down but i dont know what to look for

One good news while i was checking connections i found out that the ac connector was all spliced up.. i fixed it and now its real cold

Last edited by Projectcam94; Sep 13, 2007 at 10:59 AM.