IAT Question

[TNRGreene]

Guys with larger chargers or twins & the air filter positioned where the stock box would be. What are your IAT's. I had 175 to 191 the other night with the pass headlight out Outside temp was 95. What really concerns me is I have a Banks Super scoop & they did not cool down as the truck started to move

 

[DetailsUnlimited]

Im stock and have the scoop also and still cant get mine to come down. Bought foam insulation to go around the intake (S&B) and have sealed under hood completely off. 85 outside and temps started at 118 and went to 130. Will put my ram air hood back on and see if temps come down.

 

[JoshH]

Im stock and have the scoop also and still cant get mine to come down. Bought foam insulation to go around the intake (S&B) and have sealed under hood completely off. 85 outside and temps started at 118 and went to 130. Will put my ram air hood back on and see if temps come down.

If you are logging IAT on your truck, you are actually logging intake temps at the intake manifold. If you want to see what your air is at the filter you should log AAT.

 

[DetailsUnlimited]

If you are logging IAT on your truck, you are actually logging intake temps at the intake manifold. If you want to see what your air is at the filter you should log AAT.

Learn something new everyday!!!
Thx Josh!:thumb:

 

[calabria69]

mine runs with in a couple degrees of outside air temp.....

 

[Cougar281]

If you are logging IAT on your truck, you are actually logging intake temps at the intake manifold. If you want to see what your air is at the filter you should log AAT.

Not quite. IAT is measured at the MAF. IAT2 (on the LBZ & LMM) is measured at the intake bridge. Go out, unplug your MAF and look to see what IAT is reported as. It should be -40. If EFILive is reporting something different, their PIDs are screwed up and need to be fixed. I DO know IAT2 IS screwed up in EFILive (It's "reported" as a TCM PID) and so far have been unable to log it. So far, no one's looked into fixing it AFAIK.

Edit: EFILive's PIDS are screwed up.... Their IAT is actually the IAT2 sensor. I'm not sure how or where the AAT is measured, but it's definately NOT at the MAF (my best guess is one of the two sensors in the grille). When I disconencted the MAF, AAT remained unchanged.

Edit2: The above is for the LBZ's & LMM's. I'm pretty sure the LLY PIDs are correct.

 

[LarryJewell]

Guys with larger chargers or twins & the air filter positioned where the stock box would be. What are your IAT's. I had 175 to 191 the other night with the pass headlight out Outside temp was 95. What really concerns me is I have a Banks Super scoop & they did not cool down as the truck started to move

I have the same temps, i'm removing the banks scoop to see if anything changes

 

[JoshH]

Not quite. IAT is measured at the MAF. IAT2 (on the LBZ & LMM) is measured at the intake bridge. Go out, unplug your MAF and look to see what IAT is reported as. It should be -40. If EFILive is reporting something different, their PIDs are screwed up and need to be fixed. I DO know IAT2 IS screwed up in EFILive (It's "reported" as a TCM PID) and so far have been unable to log it. So far, no one's looked into fixing it AFAIK.

Edit: EFILive's PIDS are screwed up.... Their IAT is actually the IAT2 sensor. I'm not sure how or where the AAT is measured, but it's definately NOT at the MAF (my best guess is one of the two sensors in the grille). When I disconencted the MAF, AAT remained unchanged.

Edit2: The above is for the LBZ's & LMM's. I'm pretty sure the LLY PIDs are correct.

I did some checking on my truck a couple of weeks ago and posted about it in a thread I found about IAT and AAT on the EFILive forum. Here is what I found:

Just to re-resurrect an old thread. I have been looking at IAT temps, and notice the IAT PID had some strange characteristics such as an increase in temps under boost. There is no reason the temp should go up just because of boost if it is being measured pre-turbo. I went out to the truck and fired up the BBL. I scrolled down to IAT and checked what it was (just for the record, it was 135 F after it had been sitting for 1.5 hours). I unplugged the MAF sensor, but the temp did not change. I plugged the MAF sensor back in and unplugged the IAT sensor in the bridge, and the temp displayed no the FlashScan was -40 F. This pretty much verifies what I thought originally. I tried to check the IAT2 PID, but it caused an error code that prevented the data from being displayed.

Another update. So I put the AAT PID into my BBL file. I hooked it up to the truck and turned it on. I checked what the FlashScan said the AAT was; it said it was 91 F (actual outside temp was 76 F). I unplugged the MAF sensor and the temp drops to 73 F. Plug it back in and it goes right back up to 91 F. I unplugged it again and unplug the two temp sensors that are mounted right behind the grille, but neither one makes it change. Not sure where the 73 is coming from, but it seems maybe the temp comes from the MAF sensor unless it loses the reading from it, and then it takes it from another sensor? Is that even possible?

 

[Cougar281]

When I did the "unplug the MAF and check the AAT" test, there was zero difference. With the Tech2, there is an IAT and IAT2. Like you, I don't know where the AAT comes from, but I'm pretty sure it's not the MAF as when the sensor's unplugged, it'll show -40.

 

[JoshH]

I'm gonna have to guess maybe EFILive has their PIDs labeled differently from a Tech II. I checked it again tonight and got the same results I did previously. The actual outside air temp was 85 as displayed on the mirror. AAT was shown to be 95 and dropped to 73 when the MAF was unplugged. IAT showed to be 142 and dropped to -40 when the sensor in the valley was unplugged.

 

[Killerbee]

My conclusions last year was AAT was underhood, and IAT was dampened, indicating post CAC. IIRC it was an LMM. I would hope they (LMM and LBZ) are the same, whatever the convention.

This has always been a point of confusion, that EFILive did not follow the established convention. The term "AAT" is a misnomer, since the only time it reads near ambient, is when the motor is cold. The rest of the time, it behaves just like an airbox temp.

 

[LarryJewell]

Todd, I have the same temps no matter if the Banks scoop is installed or not, Been running around for a week now without the Banks scoop and the Iat's are still way up there. Good thing cooler weather is just around the corner I guess.

 

[LarryJewell]

It does look like there is a lot better air flow without the Banks scoop though