IAT and MS1

[EGTeric93]

so my IAT sensor works but the wire has a bad connection i need to fix..

just wondering how it effects the MS with AFR's or anything when it isnt working..

it seems i run way richer upon start up when its not working and i run a bit leaner when its not working...

im just wondering if all my tuning efforts over the last few days have been pointless since the sensor hasnt been working.

i finally have time today to take a look at it and get it fixed but just looking for opinions on how important it really is and weather or not all my tuning was pointless..

[therieldeal]

if its got a short that keeps coming on andoff it will royally mess things up. i think if you disable it in the software you can tune without it... not the best idea though since it does help fine tune things automatically based on air density vs temp

[EGTeric93]

well i took it all apart... and opened the tape.. im goin to check continuity nwerdt.com says its pin 20 on the MS. if that good it looks like it might be the plug itself that goes into the sensor... the metal just seems a lil goofed...

if its the plug itself where could i get another one?

[therieldeal]

diyautotune or practically any GM car at the junkyard

[EGTeric93]

ok cool the 2nd part of that is wat i was hoping to hear lol

ill add it to my already long list..

[EGTeric93]

ok so when i try to tune it with the IAT pluged in i need to dramatically raise the fuel ve table..

like what was 20-30% boxes need to be at 55-65% just to get it to idle properly at about 32,33 kpa with an afr of 14


i notice when its colder and the IAT is not plugged in i need to richen the fuel table. so could the colder denser air we have been having be the reason it needs to be changed that much in the ve table?

if i tune it in the middle of winter on the dyno will it be able to adjust itself for mid summer? will the IAT tell the MS that the air isnt as dense and to use less fuel such as automatically leaning out the fuel table to the target afr's?

[b-potent]

yes, the iat sensor actually affects and changes your ve table according to the readings. It will adjust the ve table according to temps, so yes, but also keep an eye on your wideband. Also make sure you have barometric correction on. Good luck

[Lex]

yes, the iat sensor actually affects and changes your ve table according to the readings. It will adjust the ve table according to temps, so yes, but also keep an eye on your wideband. Also make sure you have barometric correction on. Good luck

The IAT DOES NOT change your Ve table. The IAT is part of the fueling calculation IN ADDITION to the VE table. When it is sensing cold air, it will calculate more fuel to be added and warmer air will result in less fuel. This is why warm starts are a little tough with the MS sometimes because the IAT is heatsoaked. The amount of fuel the IAT adds and takes away based on the temperature it reads is based on a mathematical calculation. Since sometimes the readings can be off (as in the case of heatsoak) there is a table where you can scale the effect the IAT has on the fuel. It is under Advanced -> Coolant Related Air Density.

Before messing with any of this, make sure the IAT is well calibrated and that it outputs a reasonable value. It should not make such a difference that your car should not idle if it is calibrated properly.

[EGTeric93]

over on the MS forum i havnt gotton a response yet but they were saying that i would need to change my map when i hook up the IAT i just dont know if a roughly 40% increase is reasonable.. im guessing not

how do i calibrate the IAT or what would you suggest i do to get this stuff workin the way it should???


also if the barro correction is off and i plug the IAT in and set it to on is there any chance it will all fix itself?? lol i doubt i would be that lucky tho

[therieldeal]

if it is the correct GM sensor you shouldnt need to calibrate anything aside from comparing its reading to a thermometer at a few different temperatures. if its reading within a few degrees you are fine.

idk why you are so worried that you had to change the map by 40% as long as you have your AFR correct and the car is running ok whats the problem

[EGTeric93]

it just seems that the table shouldnt need to be that high.. i mean when your at idle whats the ve table number in that cell for you guys?

ive looked at other maps and there not that high... just doesnt make sense that it needs to be that high

[therieldeal]

it will all depend on how your req fuel is set, since it will skew the whole table. this is one of the reasons why you cant share fuel maps.

ms1 and ms2 also calculate fuel differently it seems, because the req fuel calculation is even different

sooo yeah. dont worry about it. as long as you have the right AFR and you'r pulling rougly 30kpa at idle its fine

[EGTeric93]

ok.. thats all i really wanted to know ill be playin with it more later after da bears game is over..

i just wanted to make sure i wasnt doin anythin too crazy