intake air temp (iat sensor)

[MISBEHAVING]

so im confused is the iat sensor in the MAF or is it on its own looked around their are some contradicting statments and i get that the it messures air temp but dose this sensor effect a vehicles idle

 

[det107]

The IAT should be located at the opposite end (the other end) of MAF. It measures the incoming air & sends info to computer in a form of resistance.
I would say the IAC (idle air control) which is also at the opposite end but on the front of throttle body, would cause rough idling-

 

[MISBEHAVING]

im aware of the idle air control and i have cleaned it and the passages in the the plunum that run to it put on a new upper intake gasket checked all vacum lines and it still has the same problem when i start it it idles up then takes for ever to come back down then eventually it will go down to 650,700 and idle fine but after u let the motor warm up and rev it falls down to about 400,450 ive set the idle up and it only chenges the intial start up idle every time it still falls to 400,450 any ideas

 

[MISBEHAVING]

so ive been thinking a little more about this whole thing and if the iat is reading it is geting cold air the engine wouldnt need as much fuel. right? creating a false lean condition right? which i have because my plugs are burnt white as a ghost

 

[Insanejughead]

It's called the Air Charge Temperature Sensor.

It's most likely located in the intake manifold. It may seem like it gets lots of hot air, since it's close to the hottest part of the engine, but if you think about the amount of air that flows through the intake, it adds a cooling effect.

Once you find the sensor, check the resistance between the two contacts with an ohm-meter. If you do, post up the numbers you get (one at ambient temperature, and one after the engine has reached operating temp.)

I have a Haynes manual that has the chart for checking, but I don't have it on my lap, nor do I have it memorized. If the sensor is way out of the range that it should read, then it's obviously bad.

 

[lil_Blue_Ford]

TPS (Throttle Position Sensor) can cause high idle issues as well if it's bad.... IIRC there might be a thing in a Haynes manual for testing it. I want to say it is something like using an analog multimeter between the middle wire and a ground while the engine is running and watch the needle for smooth movement while someone slowly opens the throttle.

Of course, I was having an issue with idle and a sort of flat spot in the throttle and testing it said things were good. I replaced it and things were good....

 

[adsm08]

The IAT on a MAF system is part of the MAF, most of the time.

On some applications it is it's own sensor and would be in the intake tube before the throttle. Some vehicles use two of them in which case the second one (IAT2) would be in the main intake runner after the throttle plate.

 

[MISBEHAVING]

alright i belive i found it in the manifold on the driver side right behind the idle air sensor looks simmilar to a o2 sensor kinda and ill try to track down a multimeter but i have electrical sensor cleaner so i might go pull it out and see how she looks

 

[Snoranger]

No, its not part of the mass air sensor on your truck. You have a 4 wire mass air, the later 6 wire mass airs (around '00 - '01) had it built in.
The '95+ (I dont know what year they were like this until.) plastic intake OHVs had the IAT sensor in the rubber air intake tube (after the mass air, before the throttle body.).

You have an aluminum upper intake... It should be on the right side of the upper intake, about 3/4 of the way back, right in front of the vacuum ports.

EDIT: I guess you found it already.

 

[shane96ranger]

Yeah, exactly what Sno said. I hope you didn't find the coolant temp sensor in the lower manifold, and if so.... I hope the motor is cool.

 

[MISBEHAVING]

i did indead find it a cleaned it semmed to help a steadier idle and as much fluction still not right though but while we are on the topic of the ect sensor my temp gauge seems to be reading awful low for the motor being hot would the ect have something to do with it or is it only the temp sending unit in the block?

 

[MISBEHAVING]

*a stedier idle and not as much fluction in idle*

 

[adsm08]

You spelled "steadier" right the first time.


I saw you said you cleaned the IAC, but have you replaced the IAC? Cleaning it is not always an effective fix.

 

[Insanejughead]

Did you check the resistance between the contacts on that sensor with a multimeter in the 200k Ohm range?

 

[MISBEHAVING]

i havent replaced it guess it wouldnt hurt to and i havnt got a multimeter that uses ohms just a chep voltmeter ill probably invest in one perty useful to have id say but as luck would have it i got the motor running a little better and my drive shaft had loosend itself and was causing a horrible vibration tightened the bolts back up and their is a lot play in the transfercase now i can grab the output saft and move it side to side at the rear of the transfercase i got the truck inspected yesterday and i asked the fella to see if he thought it was unusally loose and he thinks i through a bearing anyone have any experinse with these t cases