How IAT Sensor affects A/F
Thread Starter
Race Director
Joined: Mar 2000
Posts: 17,602
Likes: 20
From: Palm City Florida
How IAT Sensor affects A/F
We know that IAT does pull timing in certain areas as you can see on the IAT tab in LS1-Edit..
However I have zero’d out the retard amounts in all columns.. But I still think think that the values of the IAT are still used by the PCM to access another A/F table that LS1-edit does not have access to.
First zero out the K/R tables in the IAT tab.
I think this can be proved….
On a HOT day.. Plug a 4.7k ohm resistor in the IAT socket. That will force the PCM to think it’s 57 degrees out. Then run an Autotap
Then make a second run using the Stock IAT sensor.
My gut feeling is that you will see a difference in the richness…Just not sure what parameter to measure to see it in Autotap..
Anyone have any input on this?
However I have zero’d out the retard amounts in all columns.. But I still think think that the values of the IAT are still used by the PCM to access another A/F table that LS1-edit does not have access to.
First zero out the K/R tables in the IAT tab.
I think this can be proved….
On a HOT day.. Plug a 4.7k ohm resistor in the IAT socket. That will force the PCM to think it’s 57 degrees out. Then run an Autotap
Then make a second run using the Stock IAT sensor.
My gut feeling is that you will see a difference in the richness…Just not sure what parameter to measure to see it in Autotap..
Anyone have any input on this?
Former Vendor
Joined: Nov 2000
Posts: 5,607
Likes: 1
From: Houston TX
Re: How IAT Sensor affects A/F (chuckster)
I haven't pay much attention to A/F, but I can tell you that IAT definitely affect timings. With the resistor mod, I bumped the IAT temp to 145deg and my WOT timing drop down to 23-24. When I turn off the resistor, my temp was at 103 and the timing returned to 27 to 28.
Please keep us in the loop on your findings. :cheers:
Please keep us in the loop on your findings. :cheers:
Thread Starter
Race Director
Joined: Mar 2000
Posts: 17,602
Likes: 20
From: Palm City Florida
Re: How IAT Sensor affects A/F (Tuan Le)
I haven't pay much attention to A/F, but I can tell you that IAT definitely affect timings. With the resistor mod, I bumped the IAT temp to 145deg and my WOT timing drop down to 23-24. When I turn off the resistor, my temp was at 103 and the timing returned to 27 to 28.
Please keep us in the loop on your findings. :cheers:
Please keep us in the loop on your findings. :cheers:
The PCM pulls 6 degrees of timing at 145 Degrees at WOT
Look at the IAT chart in LS1-Edit.. Pretty interesting..
Safety Car
Joined: Nov 1999
Posts: 3,891
Likes: 2
From: Houston, TX
Re: How IAT Sensor affects A/F (chuckster)
THe temperature of air effects the density of the air entering your engine. You need to accurately know the temperature of the air in order to meter the air properly. IAT is very important the the A/F ratio. I am pretty sure that this is just part of the internal algorithims that the computer uses to compute A/F mixture and it is not something that you can edit, per say.
Good Luck,
Good Luck,
