What exactly does the IAT do modify in the ECU as it senses cold air or hot air?? Basically how does it make your motor run differently as the IAT senses a cold intake charge as appose to a hot charge. Hope you can understand my poorly worded question... Thanks in advance


[Modified by JDMspecEG6, 12:18 PM 11/19/2002]

 

Good question. I want to know too.

 

ok, this is what i have learnt:

the IAT is same as the ECT, they just measure different things in differnet spots.

they both trim teh A/F ratio depending on temprature.

when the IAT detects 'cold' it slightly enrichens the mixture (by increasing inj. PW by a fraction of a millisecond).

when it is 'hot' it does not do much at all.

in summary, the IAT is a very minor input to the ECU and will only really have an effect in really cold conditions...

i hope you can understand my poorly set out response

t..

 

Thanks, that's pretty much what i thought.... My friend is putting a 99-2000 Si manifold on his 1st Gen B16 and i know that the Si manifold doesn't have IAT spot plummed into it... I've build LSVTEC's before with 99-2000 Si heads and have just left out the IAT... It always has worked fine.. Latez

 

IAT is use to determine the air density, which is coupled with the MAP sensor readings to determine air mass.

If the sensor isn't connected to the harness, it'd probably throw a code (CEL 10). If the sensor probe is just hanging out in the open, then fuel metering wil be off, but it will run.


[Modified by IN VTEC, 8:09 PM 11/19/2002]

 

this would be your worst problem...

t..

 

Yea i'm not worried about that because I would never do it... I'll most likely just wire the IAT into the intake tube... Thanks for the help.. Latez

 

It will give you a CEL. It did for me...

 

If your IAT readings run beyond a set maximum in the ECU tables (say 100F as an example), the ECU will pull out timing to compensate for the hotter overall mixture. Though the IAT is coupled with TPS and MAP readings to correctly deliver fuel at WOT, it's the timing that is most affected by IAT readings (where one is concerned with power output). A few degrees retard on timing will equal a significant loss of power to us, but to the OEMs it will also mean a solid safety margin against detonation with high ambient temps and a bad tank of gas.

 

i did not know this.

how do you know this?

t..