no power to IAT! [Archive] - GrandAmGT.com Forum

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hansen01
10-27-2012, 03:05 PM
Anyone have any ideas on wth is goin on here? i had a buddy take it up to college to work on it because it was shifting super hard, and i told him to replace the IAT. Well he did that and it still shifts hard, and says that there is no power to the plug. also no power 5inches back. we are stumped here

HOYS
10-27-2012, 03:52 PM
IATs aren't powered.

zukiracer19
10-28-2012, 09:15 AM
My iat's have been giving me problems, not sure why either... it is idling like a vacuum leak and I keep getting errors... changed maf and whatnot multiple times and still no change.

shiwnath
10-28-2012, 09:38 AM
As HOYS said, they're not powered. It's just a resistor... actually the right term is thermistor. It changes resistance accordingly to temperature. The PCM just reads in this resistance and converts it into a temperature value.

AaronGTR
10-28-2012, 03:34 PM
Hard shifting is often a problem with the MAF sensor or TPS, not the IAT. IAT doesn't help the pcm determine engine load like the other two.

hansen01
10-28-2012, 05:58 PM
hmmm, ok, Because it shifts extremely hard into reverse and drive

hansen01
10-30-2012, 06:28 PM
So the only code that i am getting is a IAT code, and occasionally a maf code and a tps code. suggestions?

HOYS
10-31-2012, 03:13 AM
Bwhaha lots of problems there.

Exact codes are nice to start with. Do you clear the codes...or what?

hansen01
11-01-2012, 07:15 AM
Yea i clear them, right now its just the iat code, I'll get the the exact code later

rocketfast123
11-01-2012, 07:25 AM
Hard shifting is often a problem with the MAF sensor or TPS, not the IAT. IAT doesn't help the pcm determine engine load like the other two.

Unplug your IAT and tell me it doesn't cause it to shift hard

So the only code that i am getting is a IAT code, and occasionally a maf code and a tps code. suggestions?

What kind of air filter do you have? Over oiled K&n and can cause problems. It wouldn't hurt to test the MAF and TPS
easyautodiagnostics.com/index_gm_3.1L_3.4L/index_of_articles_1.php
video on youtube also.

hansen01
11-08-2012, 05:47 PM
Thanks rocketfast123. It has the stock filter. They changed the plug on the IAT and supposively it runs fine now. I was supposed to get it back today but idk where its at,lol so i guess il drive it for a couple days make sure its fine then get rid of the dang thing,lol

kzulfic
11-08-2012, 11:55 PM
IATs aren't powered.

They are actually powerd, but you wont get 12v you get 5v.

HOYS
11-09-2012, 12:54 AM
They are actually powerd, but you wont get 12v you get 5v.

Please tell me how you get 5v from two lines...one being a signal.

kzulfic
11-09-2012, 01:56 AM
Please tell me how you get 5v from two lines...one being a signal.

The 5 volts is a reference voltage that comes from the PCM through a resistor. The PCM measures the voltage to calculate the incoming air to adjust the timing. What the IAT is, is a thermistor where the resistance varies based on the temperature. When the temperature goes up the resistance decreases (70 ohms at 266F) when the temerature goes down the resitance increases (100,000 ohms at -40F). The 5 volts is the signal wire itself, the PCM measures the voltage using the thermistor. So when temperature is low the voltage is high when hot the voltage is low. As for getting voltage from two lines all it takes is two lines to make a complete circuit, and I have never seen an electrical component work without electricity.

sleepyalero
11-09-2012, 03:12 AM
Hard shifting is often a problem with the MAF sensor or TPS, not the IAT. IAT doesn't help the pcm determine engine load like the other two.

actually it does, my alero i didnt have the IAT plugged in and it would shift really hard into the gears when i had the auto in there.

shiwnath
11-09-2012, 05:14 AM
The 5 volts is a reference voltage that comes from the PCM through a resistor. The PCM measures the voltage to calculate the incoming air to adjust the timing. What the IAT is, is a thermistor where the resistance varies based on the temperature. When the temperature goes up the resistance decreases (70 ohms at 266F) when the temerature goes down the resitance increases (100,000 ohms at -40F). The 5 volts is the signal wire itself, the PCM measures the voltage using the thermistor. So when temperature is low the voltage is high when hot the voltage is low. As for getting voltage from two lines all it takes is two lines to make a complete circuit, and I have never seen an electrical component work without electricity.

This is actually correct. I was wrong in my previous post. Kinda sad because this stuff is a key part of what I'm currently learning in school lol. Just used a thermistor this week actually.

rocketfast123
11-09-2012, 07:38 AM
The 5 volts is a reference voltage that comes from the PCM through a resistor. The PCM measures the voltage to calculate the incoming air to adjust the timing. What the IAT is, is a thermistor where the resistance varies based on the temperature. When the temperature goes up the resistance decreases (70 ohms at 266F) when the temerature goes down the resitance increases (100,000 ohms at -40F). The 5 volts is the signal wire itself, the PCM measures the voltage using the thermistor. So when temperature is low the voltage is high when hot the voltage is low. As for getting voltage from two lines all it takes is two lines to make a complete circuit, and I have never seen an electrical component work without electricity.

A useful post on GAGT by another person that doesn't bash another person...

http://www.reactiongifs.com/wp-content/gallery/omg/omgomgomgomgomg.gif

kzulfic
11-09-2012, 09:50 AM
A useful post on GAGT by another person that doesn't bash another person...

http://www.reactiongifs.com/wp-content/gallery/omg/omgomgomgomgomg.gif

I try to be as nice as possible untill you get idiots posting links to ebay for random junk. But at that point I think all is fair game. lol

HOYS
11-09-2012, 11:25 AM
Powered as in a MAF I guess.

Either way, yeah.